Tartu Observatory
Annual Report, 2004

Contents

Foreword


2004 remains in the history of Estonia first of all as the year of joining NATO and European Union. Those events were perhaps not so much discernible in everyday life of scientists, as Estonia could participate as equal partner in the EU Framework Programmes for some years already; we have also benefited from NATO science programmes. It is somehow symbolical, though, that on the very first days of May our Ph.D. student Taavi Tuvikene moved to Brussels, to continue his studies in the Vrije Universiteit Brussel under supervising by Prof. Chris Sterken. Several European astronomers had a good opportunity to visit Estonia immediately after it joined EU: on May 7-8 we arranged the annual meeting of the Board of Directors of the journal ''Astronomy and Astrophysics" in Tartu. Together with publishers and editors, it attracted almost 30 people, many of whom visited the Observatory at Tõravere, too.

40 years of the Observatory at Tõravere was an important motto for the year 2004. Although beginning of astronomy in Tartu can be dated back to almost 200 years, opening of the new observatory complex on September 14-15, 1964 was a very essential event for the whole Estonian science. On October 1, 2004, a festive meeting was held to commemorate this event with more than 120 former and present colleagues and invited guests participating. In his speech, Academician Jaan Einasto summarized the research done during 40 years. Vice-director Tõnu Viik remembered what else has been done at Tõravere besides science - his report ''Tõravere in the Estonian cultural history" attracted a wide-scale interest. The Estonian astro-musician Urmas Sisask decorated the meeting with his piano pieces. This sunny day will also be remembered by 10 oak-trees, planted in the honour of famous scientists who had worked at Tõravere.

It is appropriate to remember the inventor and telescope constructor Bernhard Voldemar Schmidt (1879-1935) born on the Naissaar island near Tallinn. In co-operation with Estonian Academy of Sciences we arranged a seminar on occasion of his 125th birth anniversary on April 13 in Tallinn.

Concerning everyday life at the Observatory, it is worth to note that thanks to the state investments, we were able to repair the main inner roads of the Observatory. Besides the oak-trees mentioned above, the mountain pines donated by the Ministry of Education and Research decorate the sides of the renovated road to the telescopes.

Let reminescenses from the laborious and festive year 2004 render us a reasonable optimism to look into the coming years.



Laurits Leedjärv

Director



Summary

Research projects and grants

Most of the finances for basic research in Estonia are channelled through target financed projects. In 2004, research in the framework of three projects was continued (1 kEEK = 1000 EEK = 63.90 EUR):

In addition, the Estonian Science Foundation financed 12 grant projects from our Observatory:

  1. Grant 4695: J. Einasto - Evolution of the Universe from the past to nowadays - 240 kEEK.
  2. Grant 4696: T. Nilson - The analysis of time series of satellite images to estimate vegetation change - 195 kEEK.
  3. Grant 4697: J. Pelt - High precision statistical and computational methods in astronomy - 70 kEEK.
  4. Grant 4699: M. Sulev - Radiation regime, architecture and biomass production of the energy forest (willow and grey alder) in Estonia - 160 kEEK.
  5. Grant 4701: A. Sapar - Stellar spectra and radiative transfer: from theory to model calculations - 100 kEEK.
  6. Grant 4702: J. Vennik - Structure of galaxies and their subsystems at different epochs - 190 kEEK.
  7. Grant 5003: T. Kipper - Evolution of luminous non-stable stars - 215 kEEK.
  8. Grant 5004: O. Kärner - Modelling the global temperature series - 35 kEEK.
  9. Grant 5347: M. Gramann - Dynamical evolution of superclusters, clusters and galaxies in the Universe - 88 kEEK.
  10. Grant 5348: U. Veismann - The influence of atmospheric optical parameters on the ground-level solar UV radiation - 100 kEEK.
  11. Grant 5760: I. Pustylnik - Physical processes and evolutionary trends in close binary systems during the early stages of white dwarfes formation - 75 kEEK.
  12. V. Russak participated in the grant 5857 led by H. Ohvril from Tartu University (55 kEEK to Tartu Observatory).


Some other projects and contracts:

A scientific report about the activities within all these projects and topics will be given in Chapters 6-8.


Personnel and structure

There were no changes in the structure of the Observatory during 2004. The number of the people employed increased a little bit, mainly due to some younger researchers who joined our staff.

From January 1, 2004 Anu Reinart works as a part-time research associate in the group of remote sensing of vegetation. She returned to Estonia after post-doc years in Uppsala University, and being successful to receive the Marie Curie reintegration grant, she works on a full-time position starting from December 1, 2004. From February 1, 2004 Vladislav-Venyamin Pustynski works as a part-time research associate in the group of theoretical astrophysics. As of May 1, Alar Puss and Matti Mõttus work on the position of research associates, elected by the Scientific Council. The latter defended his Ph.D. thesis successfully on October 15. Thanks to the post-doc grant added to the topics of atmospheric physics, we could recruit Oleg Okulov to work as a post-doc since April 1. Research associate Peeter Traat is working on the basis of a temporary contract from May 1. Ilmar Ansko has been employed as a full-time engineer in the group of remote sensing of atmosphere from January 1, and Tiina Liimets as a part-time technician in the group of stellar physics from August 16.

On April 6, 2004 the five year term of the directorship of L. Leedjärv ended. He took part in the public contest, announced for this position in January, and on March 2, the Scientific Council elected him to the director for another five year term.

On September 25, 2004 our long-term colleague Rutt Koppel (65) from the group of remote sensing of atmosphere passed away after a valiant battle against cancer. Having kept modest positions of a laboratory assistant and of an engineer, she actually contributed to tens of scientific publications in the field of atmospheric ozone, solar ultraviolet radiation and atmospheric research from space.

As a result of all the changes, there were 58 people in the main staff of the observatory on January 1, 2005. 34 of them were on the positions of research associates or senior research associates. Adding one engineer, the post-doctoral associate, the vice-director and the director, brings the number of people directly involved in research up to 38.


Rewards

The city of Tartu honoured Academician Jaan Einasto by electing him to honorary citizen of Tartu, in spite of fact that he was actually one of the first inhabitants of Tõravere, moving here in 1961.

The Heino Eelsalu fellowship foundation at the Estonian National Culture Foundation awarded the fellowship for 2004 to Ken Kalling from the Estonian National Defence College.

Letters of thanks from the Estonian Ministry of Education and Research and from the Estonian Academy of Sciences remain to remember the 40th anniversary of opening the new observatory at Tõravere.


Instruments and facilities

The group of sensing of vegetation belongs to the Centre of Excellence for Basic and Applied Ecology, headed by Prof. Olevi Kull, Tartu University, Institute of Botany and Ecology. In collaboration with this Centre of Excellence the group of sensing of vegetation purchased a high precision fiber optic spectrometer FSP 350-1050P (Analytical Spectral Devices, Inc.). Its working diapason is 350-1050 nm and resolution 1.4 nm. The spectrometer is equipped with several lenses that makes it possible to study both leaf optical properties and radiative transfer in plant canopies.

An experimental copy of the field spectrometer, developed by M. Pehk for the spectral interval 800-1700 nm, passed a preliminary testing in field conditions.

A portative UV-A and UV-B instrument DD 9721 of Delta Ohm company was obtained. A fiber-optic spectrometer AvaSpec-256 was installed and connected to the computer network.

Our 8-node cluster computer was upgraded with five new Pentium IV type 2.8 GHz computers added.

Astronomical observations were continued as usually. The 1.5 m telescope was used for spectroscopic observations during 47 nights, and the 0.6 m telescope for photometric observations during 15 nights.


Budget

The total amount allocated from the state budget directly to the Observatory was 11 956 kEEK and it consisted of 7209 kEEK for target-financed projects, 2668 kEEK for infrastructure, 1529 kEEK as grants from Estonian Science Foundation, 500 kEEK for renovation (roads) and 50 kEEK for investments into information technology.

The expenses were divided approximately as follows:

In addition, 1056 kEEK from contracts with European Union and other organizations were allocated to the Observatory, part of which will be usable in 2005.

The mean monthly salary of research associates and senior research associates was approximately 9826 EEK (628 EUR) by the end of 2004.


Scientific Council

According to the new Statute of the Observatory, the list of the members of the Scientific Council was changed a little bit, and as of September 2004, it is as follows:
  1. L. Leedjärv, director, Ph.D. (chairman),
  2. T. Viik, vice director, D.Sc. (vice-chairman),
  3. K. Eerme, senior research associate, Ph.D.,
  4. J. Einasto, senior research associate, D.Sc., Est. Acad. Sci.,
  5. E. Ergma, speaker, Parliament of Estonia, D.Sc., Est. Acad. Sci.,
  6. T. Kipper, head of department, D.Sc.,
  7. A. Kuusk, senior research associate, D.Sc.,
  8. T. Nilson, head of department, D.Sc.,
  9. J. Pelt, senior research associate, Ph.D.,
  10. R. Rõõm, professor, University of Tartu, Ph.D.,
  11. E. Saar, head of department, D.Sc.,
  12. A. Sapar, senior research associate, D.Sc., Est. Acad. Sci.,
  13. P. Tenjes, assistant professor, University of Tartu, Ph.D.

The Scientific Council held 11 meetings in 2004. The following scientific reports were presented:

January - E. Saar: On the models of the Universe.
February - J. Einasto (on the occasion of his 75th birthday): Cosmology in Tartu Observatory.
March - L. Leedjärv: High-velocity jets in astrophysics.
April - V. Russak: On the transparency of the atmosphere.
May - J. Vennik: On small galaxy groups.
September - M. Burmeister: Spectroscopic study of the symbiotic star AG Draconis.
October - M. Einasto: On deep surveys of galaxies.
November - A. Aret: Isotopic anomalies of heavy elements in chemically peculiar stars.
December - R. Poolamäe: On the modelling of spectra of hot stars.

Some other activities of the Council:


Public relations

Tartu Observatory continued to act as a popular destination of excursions, receiving about 4900 visitors in 193 groups in 2004.

Our guides M. Ruusalepp, A. Puss, K. Annuk, I. Kolka, I. Pustylnik, L. Leedjärv, J. Vennik and T. Viik did a great job to introduce the visitors with the Observatory and with the news of astronomy and atmospheric science.

The School of Exact Sciences at Tartu University organized a summer school for teachers of physics. The participants spent one day in the Observatory, hearing lectures on the latest developments in astronomy and atmospheric physics.

E. Tago continued his activities in the Astronomy Club of the Old Tartu Observatory and Science Centre AHHAA with planetarium shows, lectures, excursions and public demonstrations of the sky. He was one of the organizers of the 9th annual meeting of Estonian amateur astronomers at Krabi, Võrumaa from August 11 to 16, 2004.

As usually, our scientists gave public lectures, were interviewed in radio and TV broadcasts and answered many phone calls.

We published the Observatory Calendar, it was the 81st year of issue.


Forward look

''Predictions are always difficult to make, especially, if they concern future". This quote is attributed to the famous physicist Niels Bohr, whose work is appropriate to remember in 2005 which has been declared a World Year of Physics - to commemorate publishing of three legendary articles by Albert Einstein in 1905. Those geniuses deserve remembrance - not so much, because we expect emerging of new einsteins and bohrs from our own Observatory in the near future, but because here the general logics of development of science and society is well illustrated. Hardly could someone foresee practical applications to Einstein's theory of photoeffect 100 years ago, or appreciate quantization of the states of the electron by Bohr a little bit later. However, not knowing those phenomena, we would not have many things from our contemporary everyday life, including the computer which was used for preparing the present text.

Fundamental research without direct practical application is one of the main activities of Tartu Observatory, too. Although interest to applications of our research, especially that done at the department of atmospheric physics, seems to be arising in Estonia, our main mission has been and will be to contribute into a general ''database" of human knowledge. Our task is to advertise this mission in the Estonian society, and to prove that fundamental research is possible and required in small states, too. The World Year of Physics 2005 should give opportunities to fulfil this task, and at the same time, be a preparation for the year 2009 which presumably will be declared the Year of Astronomy - to commemorate passing of 400 years from first usage of telescope by Galileo Galilei.

In a short time horizon, a new hope for development of the Observatory is secured by a new kind of financing research introduced in 2005 - so called basic financing. Distribution of those funds between the research institutions is not known by the time of writing the present Annual Report, but we hope that Tartu Observatory will obtain appropriate part of those funds and could use it first of all for being more attractive for young researchers and for increasing our international visibility.


Acknowledgements

Many associates were supported by various institutions throughout the world. Herewith we cordially thank:


Evolution of structure in the Universe from deep past until the present

Large-scale properties of galaxy systems

Already several years M. Einasto, J. Einasto, E. Tago and E. Saar have studied the properties of galaxy systems (groups and clusters) in different environments. For galaxies there exists a well-known morphology-density relation: early type galaxies and luminous galaxies are located in high density regions while low luminosity late-type galaxies are preferentially located in low density regions. In last years due to the advent of new deep surveys of galaxies (SDSS and 2dF surveys among others) the number of studies of the properties of galaxies in various environments has increased rapidly. However, the study of galaxy systems in different environments is only in the beginning.

Our earlier studies of galaxy groups from the Las Campanas Redshift Survey and from the SDSS EDR showed that in high density regions the groups of galaxies themselves are also richer, have larger masses, luminosities and velocity dispersions than galaxy groups in low density regions. Now we continued these studies using new observational data.

E. Tago completed his catalogue of groups and clusters of galaxies based on the Sloan survey first data release (SDSS DR1). He applied Friend-of-Friend (FoF) method to carry out cluster analysis for about 110 000 galaxies to generate groups. He studied the spatial distribution of these groups and found the density field in collaboration with co-authors.

E. Tago has also completed another extended catalogue of groups based on the 2-degree Field Galaxy Redshift Survey (2dF GRS) which includes about 250 000 galaxy redshifts. To generate the group catalogue which consists of about 18 000 groups, E. Tago applied more developed FoF method with a group cleaning procedure to exclude groups which have too high velocity dispersion. The obtained catalogue will be used to study group luminosity function, density field and group properties in various large scale environments. On both group catalogues papers and conference reports have been prepared and submitted.

E. Tago continued the compilation of the database of rich clusters in collaboration with H. Andernach (Mexico). The catalogue contains 3936 redshifts and 1937 velocity dispersions for these clusters. It has been and will be used to study spatial distribution of the clusters and matter density parameter.

E. Saar and J. Einasto investigated the luminosity function of groups of the 2dF GRS. They demonstrated that the luminosity function of main galaxies of groups can be represented by a power function with different power index at low and high luminosity ranges. Their approach is based on the halo model. Here the observed luminosity distribution of galaxies can be represented as a mixture of the luminosity distribution of the main galaxies of haloes, and of the galaxy luminosity functions within haloes. For observational haloes they used the new 2dF GRS galaxy group catalogue by E. Tago. If the first luminosity function is more or less universal and does not depend on the halo richness, the inner luminosity function feels the halo richness. None of the luminosity functions can be described by the Schechter form (gamma-distribution). They also found that when fitting the Schechter function to the observed luminosity distribution, one obtains narrow confidence regions for its parameters, but the goodness-of-fit test says that the fit itself is extremely bad (the residual dispersion per degree-of-freedom is around 100, not 1, as normal). They used power laws with different asymptotics, which describe the observed luminosity functions much better. This work is in progress; it forms a part of a 2dF group study project.

Another project, where E. Saar used the 2dF GRS data, is the morphological analysis on the density field defined by this catalogue. Last year he developed together with V.J. Martínez, J.-L. Starck, and D.L. Donoho, an adaptive method of estimation of the density of realizations of point processes, based on wavelet analysis. This year they developed it further, testing it on Voronoi distributions of different morphology and on $N$-body simulations, and applied it to the 2dF GRS catalogue. The volume-limited catalogues necessary for morphological analysis, were kindly provided by the 2dF GRS team. They found that the observed sample approaches the Gaussian random field morphology, a usual cosmological standard, only for very large smoothing scales, and that the real morphology is extremely non-Gaussian. They found the significance limits for the differences by Monte-Carlo methods, and studied the possible cosmic variance, using over 20 $N$-body models. The project is in progress; the first paper with the results is accepted for publication, two following papers are close to completion.

The same ideas are involved in the work by E. Saar on multi-resolution analysis of cosmological fields. This starts from an alternative picture of density, which sees the density fields as a sum of densities of different scales. This approach is natural for the analysis of the evolution of cosmological fields, allowing us to estimate how much of the initial information has been preserved in the present non-linear fields. For that the à trous analysis, well known in the wavelet theory, was used. Examples of such an analysis were presented in a talk at JENAM, and multi-resolution morphological analysis will be the subject of our second paper on the 2dF data. Similar studies, comparing the à trous decomposition of the SDSS density field with the standard Fourier analysis were continued together with J. Einasto. The advantage of wavelet methods, compared to the Fourier analysis, is that they are local and allow better to separate the dynamics at different spatial scales.

Last year E. Saar started a project to describe the large-scale filamentary structure, using marked point processes (together with R. Stoica, J. Mateu, and V. Martínez). This year they published the first paper on that (technical report of Universidad de Jaime I, Castellon). They started working to describe 3-D filaments; this is more difficult. Presently they are using $N$-body simulations as test cases, and plan to apply the method, tuned on $N$-body models, to observational data.

M. Einasto showed that Abell clusters in high density environment are richer than Abell clusters in low density environment.

M. Einasto began the study of the properties of superclusters of Abell clusters that are crossed by the 2dF survey of galaxies using data about groups of galaxies in superclusters. She used the group catalogues compiled by E. Tago, as well as the publicly available catalogues of groups from 2dF survey (2PIGG, Eke et. al. 2004, astro-ph/0402567). Preliminary results of this study show that, in accordance with the previous results, in high density regions groups of galaxies are richer, more luminous and have larger velocity dispersions than groups of galaxies in low density regions.

M. Einasto began the study of the galaxy distribution from the GOODS survey of galaxy redshifts.


Galaxy groups

J. Vennik continued the photometric study of the nearby groups of galaxies with an emphasis on the detection of new low surface brightness dwarf group members and on the search for evidence of mutual interactions in the morphology and structural characteristics of bright and faint group members. According to the present knowledge small groups are a proper place to study galaxy-galaxy interactions, since the galaxy encounters in groups occur at lower relative velocities, compared to galaxy clusters, and could severely modify their original morphology. In 2004, three groups around the galaxies IC 65, NGC 2655 and NGC 6962, respectively, have been studied in more detail. In the area of 60 x 60 arcminutes centered on IC 65, 105 galaxies have been selected and classified according to their surface brightnesses, colours and morphology. As a result, four new dwarf galaxies have been found, and the group membership of two of them has been confirmed by H I measurements. The dynamical parameters of this group (mass-to-light ratio $ \sim$ 35, crossing time $ \sim$ 1.2 billion years) show that the IC 65 group of galaxies is probably well mixed and the fraction of dark matter is $ \sim$ 10 times higher than that of luminous matter. The distorted outer isophotes of both the stellar and the gaseous components of its bright members and the enhanced star-forming activities in two dwarf companions of the principal galaxy IC 65 could have been caused by interactions between the group members. On the other hand, the lack of hot X-ray emitting gas and elliptical/spheroidal galaxies indicate the relative youth of this particular group. The results of this study have been presented at the international conference held on Crete and have been prepared for publication.


Double galaxies

M. Jõeveer and a Ph.D. student A. Lõhmus studied integral properties of isolated binary galaxies from the catalogue by Karachentsev (1987). For nearly half of the pairs new more accurate redshifts were found from the CfA Redshift Catalogue, which were used in the new reduction of data. The pairs with mass-to-luminosity ratios $M/L$ $< 100$ in solar units ($H_0$=75 km/s/Mpc) were considered to be physical pairs. The pairs with $M/L$ $> 300$ were regarded as optical pairs; members of optical pairs are mostly single galaxies and they were used as a sample of single galaxies. It was found that mean absolute luminosities of member galaxies of physical pairs are practically equal to the luminosities of member galaxies of optical pairs (single galaxies). This equality of mean luminosities of singles and doubles is valid in samples with different morphology (in case of E+E, E+S and S+S pairs) and as a total. In an earlier analysis Karachentsev (1987, 1990) concluded that member galaxies of binary systems are noticeably brighter (1.7 times) than single galaxies. The difference with this result is explained by the fact that the sample of single galaxies used by Karachentsev lacked complete redshift data and the subsample with redshifts was strongly biased towards nearby galaxies, correspondingly the mean luminosity of these galaxies was biased to lower luminosity.


Single galaxies

P. Tenjes and A. Tamm, a Ph.D. student of Tartu University, continued investigation of the structure of visible and dark matter in distant galaxies. Two types of models for the visual components have been constructed: on the basis of the surface density distribution (exponential disk) and on the basis of the more flexible spatial density distribution. For all galaxies the light distribution in the outer parts is clearly steeper than a simple exponential disk. On the basis of the more detailed spatial density models it was found that for galaxies at redshift $z\sim$ 0.9 the mean $M/L_B$ = 2.3. Comparing this result with the mean stellar $M/L_B$ for local Sb galaxies no significant evolution is detected. An explanation for this negligible dependence can be found in chemical evolution models. The mean central density of dark matter haloes at redshift $z\sim$ 0.9 in the isothermal model was found to be $\rm0.020 \pm 0.008~M_{\odot}/pc^3$, again showing almost no evolution with redshift.

Kinematics of the modelled galaxies were compared with different dark matter density distributions (isothermal distribution, Burkert's model, Moore distribution, Navarro-Frenk-White model). Except to the ''cuspiest" one by Moore et al., all the other distributions fit within the error bars. However, the agreement of the NFW model with the observations is clearly worse than in case of the first two models. At present, on the basis of available data it is not possible to prefer the isothermal model to the Burkert's model and vice versa.

Figure: Four galaxies modelled, at redshifts $z\sim$ 0.5 - 0.9. The image of the latter galaxy, belonging to the Hubble Deep Field South, is clearly better than the remaining ones. Just looking of these images demonstrates the significantly higher quality of deep surveys in comparison with usual HST observations.



Structure of the Galaxy

When in the previous years the study of the neutral gas in the Galaxy was based on the Leiden-Dwingeloo Northern sky H I survey, then now the extension of this survey to the Southern sky is nearing completion. These observations have been completed in Argentina, in Instituto Argentino de Radioastronomía. The reduction of the observations was made in Radio Astronomy Institute of the Bonn University. Due to the contacts from the 1990s U. Haud has participated in this reduction. He has carried out the Gaussian decomposition of different versions of the reduced survey, prepared in Bonn, and from the statistical analysis of the obtained results he has estimated the quality of the reduced profiles and their agreement with the Northern sky data. Considering these estimates, some shortcomings in the reduction procedure have been corrected: the removal of periodic perturbations has been included into the base-lining and the initial interpolation algorithm has been replaced.

U. Haud also continued the analysis of the results of the Gaussian decomposition of the Leiden-Dwingeloo survey. He studied the distribution of the widths of the obtained components and the dependence of these distributions on the mean velocity of the Gaussians. The results extend those published earlier by G. L. Verschuur (1989, 1994, 1999, 2004). As U. Haud has used the database about 100 times larger than the one used by Verschuur, it was possible to study these distributions at different velocities of the gas. He proposed that the existence of different line-width classes may result from the presence of gas populations with different dynamical properties in the Galaxy. Using the line-widths we can most clearly distinguish the population, corresponding to high-velocity hydrogen clouds (HVC), which has been so far recognized only on the basis of their unusual velocities relative to the Sun. This new approach enables us to study HVCs also at velocities not so different from those of the normal Galactic gas.

Figure: HVCs, as identified from their line-widths (top) and velocities (B. Wakker 1990, bottom). The shades of gray represent the emission intensity of the clouds. The names of the largest complexes are indicated.


Dynamics of dark matter and $N$-body models

E. Saar continued $N$-body work by analysing light-cone models. The first (MLAPM light-cone) models were developed by I. Suhhonenko and P. Heinämäki in Tuorla; they extracted also the dark matter haloes. E. Saar worked on breaking these haloes into individual galaxy haloes, on cleaning the haloes from unbound particles, and on combining several light-cone output files into one halo catalogue. The first paper on these light-cones is being completed, and new simulations are in progress. The first natural application of the model results is comparing them with extremely deep surveys. Another application, also in progress, is modelling the SZ (Sunyaev-Zeldovich effect) cluster signal for the Planck satellite. They have found mutual interests with the Spanish ALHAMBRA survey project, where the very deep light-cones will be observed; they need model data to tune their data processing software.

I. Suhhonenko finished his 10 months CIMO fellowship period in Tuorla Observatory in August 2004.

I. Suhhonenko's work was devoted to developing numerical $N$-body simulations - especially so called light-cone simulations and its applications for the study of Dark Matter (DM) halo properties. Theoretical research and modelling in this field is especially important now, before the Planck-satellite mission. The results of the light-cone simulations will be compared with deep redshift surveys (DEEP2, GOODS), and will be used further to predict the SZ signal from distant clusters of galaxies, that the Planck mission will observe.

Data handling has vital role in such large simulations. One computational challenge is the DM halo extraction from the raw data of the lightcone simulations. On the basis of FoF algorithm I. Suhhonenko developed a software package, which allows to select DM haloes from simulations using different criteria as a function of redshift. As a result we have a light-cone compatible cluster algorithm and a significant speed-up in processing of light-cone simulations.

The simulations were performed using the MLAPM code with the light-cone addition made by E. Saar. The light-cone simulations are consistent with the scale of the Hubble Ultra Deep Field observations (the simulation extends to $z=6$ and sky coverage is $120' \times 30'$).

At present, the Tartu-Tuorla common cosmology group is continuing with more detailed study of the output data of light-cone simulations and the evolution of the DM halo properties (eccentricity, velocity, mass). This can be directly compared with current and future observations and could give us better understanding of the evolution of galaxy clusters.

E. Saar supervises the work of two master students, I. Pärn and L.J. Liivamägi. I. Pärn is studying the structure of observed galaxy clusters (cluster fingers) in redshift space. She found the clusters in several $N$-body models of different resolution (several hundred clusters, altogether), and calculated their velocity distributions. At the moment she is working on analytical approximation of the distributions and on studying the dependence of the distributions on halo mass. This done, the results can be used to estimate the dynamical status of a cluster, and to get alternative estimates of cluster masses.

L.J. Liivamägi developed further a wavelet method to find groups and clusters of galaxies in redshift catalogues. He introduced a semi-radial spatial grid, which is natural for cluster wavelets. He also changed the previous continuous wavelets with the à trous method, speeding up the algorithm, studied the connectivity of clusters at different wavelet scales, and developed parallel algorithms for application of the method to real catalogues. Both students' work is in the final stage.


Properties of dark haloes

The dependence of the properties of galaxy systems on their environment, found from observational data, has not been studied yet using $N$-body models. Therefore, M. Einasto together with I. Suhhonenko, P. Heinämäki, J. Einasto and E. Saar studied the properties of haloes from LCDM simulations. The simulations were performed using the MLAPM code, which uses adaptive mesh techniques: new sub-grids are created in regions where the density exceeds a certain threshold. Simulations were performed in a 200 Mpc cube, dark matter haloes were found using the FoF algorithm with the linking length of 0.23 in units of the mean particle separation. The spatial densities around haloes were found using the distance to the halo's 5th neighbour halo.

Figure: The spatial distribution of haloes in regions of different density in a slice of thickness of 50 Mpc. The left panel shows the spatial distribution of haloes. Filled symbols denote haloes in a high density environment, open circles and crosses denote haloes in a low density environment.

Figure: The velocity vectors of haloes.

The results of this study show that haloes in a high density environment are richer, more massive, have larger virial radii, have larger rms velocities and larger peculiar velocities, and are more spherical than haloes in a low density environment. Also, low mass haloes in the vicinity of high mass haloes are themselves richer, more massive, slightly more spherical and have larger rms velocity dispersions than low mass haloes farther away from high mass haloes. The larger the mass of the parent halo, the larger are the velocities of low mass haloes in the vicinity of high mass haloes. Our study indicates the importance of the role of a high density environment that affects the properties (formation and evolution) of galaxy systems. In high density regions haloes formed earlier, and are more evolved than haloes in low density regions, in accordance with the scenario of the hierarchical formation of the structure in the Universe.

For this study M. Einasto generated a series of animations that show the spatial distribution and movements of dark matter haloes. These animations, as well as the catalogue of dark matter haloes are available from the web pages of the group of cosmology (http://www.aai.ee/~maret/EEH.html).

J. Einasto analysed the evolution of the density field in numerical simulations. The goal of the study was the explanation of the environmental dependence of cluster luminosities. The evolution of clusters in high- and low-density regions was compared. Superclusters are regions where density perturbations of large and medium wavelength combine to generate high-density peaks. Here non-clustered particles flow toward clusters and their fraction rapidly decreases, clusters also grow due to merging effects. Large low-density regions (voids) are regions where large-scale density perturbations have negative amplitudes. In these regions the mean density decreases continuously; for this reason clusters almost do not evolve, and a high fraction of particles remains non-clustered.

For light-cone simulations M. Einasto generated a series of fly-through animations which visualize different properties of haloes in these simulations (masses, velocities, shape and others).


Velocities of galaxy clusters

In 2004, M. Gramann and I. Suhhonenko continued to study the peculiar velocities of galaxy clusters. The peculiar velocities of galaxy clusters are connected with the density fluctuations in the dark matter field. In this study the dark matter was assumed to be the cold dark matter. The initial density and velocity fields were assumed to be random Gaussian fields. M. Gramann and I. Suhhonenko used two methods to define model systems: the FoF method and the definition of the clusters as maxima of a smoothed density field (DMAX). To find the smoothed density field, different smoothing radii were used. M. Gramann and I. Suhhonenko studied the mean peculiar velocities and the velocity probability distribution at different redshifts starting from redshift $z=10$. Numerical results show that the mean velocity of DMAX clusters is practically independent of the cluster mass, except for the clusters with very small masses, were the mean peculiar velocity is somewhat lower (approximately 5 per cent). The mean velocity of FoF clusters declines with the growth of the cluster mass. It is due to the fact that in this method, the size of a massive cluster is larger than the size of less-massive clusters. The results were compared with the expectations from linear theory. The linear theory can be extrapolated to the non-linear phase by using two approaches: we can start from the sizes of the clusters or we can base on the cluster masses. In this study both possibilities were investigated. A preliminary version of this study was submitted to MNRAS in 2003. Now this study has been substantially extended and improved (different redshifts, different smoothing radii, different linear base).

In order to investigate the dynamical evolution of galaxy systems exactly, we must model the evolution of galaxies in $N$-body simulations. There are two possibilities to do this: we can model the hydrodynamic processes (gas dynamics, formation of stars) and the formation of individual galaxies precisely or we can model the formation of galaxies statistically. M. Gramann studied the last possibility in more detail. One way to describe the galaxy formation statistically is to use the so called halo model, where it is assumed that galaxies are located only in a certain type of systems and that their statistical properties are given only by the mass of these systems.

However, at present it is not clear which methods to define the systems are most suitable to model galaxies. Also, the relation between galaxies and the dark matter distribution inside the systems needs further study. In order to study this problem, we can use existing data for the observed galaxy systems and also existing hydrodynamic $N$-body simulations.


Modelling of galaxies

Chemical evolution of galaxies

The Hubble Space Telescope on its orbit around the Earth and big Earth-based telescopes continue to produce observational information on faraway, young and even forming galaxies, and deep, high-resolution observations of galaxies in the local Universe. This information coupled with theoretical knowledge from stellar evolution theory allows to address the cosmological question, how the appearance of galaxies, the composition of their matter and their light will change with time.

At our observatory, P. Traat continued working on galaxy evolution, improving computational aspects and prescriptions in his code package. He studied galaxies at high redshifts, for which there were available observational photometric or spectral data for longer wavelength range, and matched them with models to estimate their age and star formation rate. He also computed the time-integrated spectra of homogeneous coeval stellar populations with different initial chemical compositions and initial mass functions. The goals of that work were to investigate and calibrate the dependence of the summarized emission in different wavelength ranges as a function of the chemical composition and to find numerically the amount of radiation energy, generated by given stellar population per unit mass of main nucleosynthetic products. These quantities have cosmological significance, since they calibrate the global relationship between cosmic nycleosynthesis and radiation. The results show that composition-caused flux differences can be rather impressive, extending to a factor of 10 in far-UV and $ \sim$ 2 in infrared.


Dynamical models of galaxies

P. Tenjes and E. Tempel, a M.Sc. student of Tartu University, continued developing detailed hydrodynamical models of nearby galaxies and analysis of the constructed models. The models assume triaxiality of the velocity dispersion ellipsoid. In 2004 the modelling software was modified significantly and several bugs were fixed. The program calculates all components of the velocity dispersion ellipsoid, centroid velocities and line-of-sight velocity dispersion integrated over all galactic populations. After some analysis of simple analytical gravitational potentials the developed software was applied in modelling of an edge-on spiral Sa galaxy M 104. For this galaxy line-of-sight velocity dispersion profiles along several cuts are available giving an idea about the behaviour of dispersions in the whole meridional plane. As an initial preliminary model an earlier model, basing on the light distribution and gas rotation curve was used. This earlier model was modified first due to newer globular cluster data and due to the revised distance of the galaxy. For the final model the theoretical calculations were compared with observations along two cuts parallel to the major axis and three cuts parallel to the minor axis. The model fits with observations rather well. As a result of the developed models, it is possible to determine the dark matter density distribution in central regions of stellar systems more precisely.


Structure, chemical composition and evolution of stars

Late-type stars

The observing programme of the post-AGB stars after the final helium-shell flash was continued by T. Kipper and V.G. Klochkova (Special Astrophysical Observatory, Russia). In 2004 the spectra of nonvariable hydrogen deficient carbon stars (HdC) were observed.

Using the high resolution (R $\approx$80 000) and high $S/N$ (>300) spectra of five cool carbon stars made publicly available by the VLT UV-Visual Echelle Spectrograph (UVES) Paranal Observatory Project, the available line-lists (mainly the list by R.A. Bell, http://ccp7.dur.ac.uk/ccp7/DATA/lines.bell.tar.Z) were checked as sources for carbon stars analysis (T. Kipper). The second line-list was SCAN-CN by Jørgensen & Larsson (1990), and the third one generated at the Indiana University by Alexander (1991). The spectrum synthesis was used together with model atmospheres computed for every star.

Although the Bell's list was originally not assigned for the studies of carbon stars it turned out that it could be used for this purpose in a broad spectral region 420-1040 nm. In some subregions the CN lines data should be replaced by the data from the SCAN-CN list, and the additional C$_2$ Swan system lines should be included together with the C$_2$ Phillips bands from the Alexander's list. At the wavelengths greater than 900 nm the redundant lines of the CN red system $Q_3$ branch should be removed.

In 2004 the photometric evolution of the peculiar variable star V838 Mon and its light echo has been monitored with the 0.6 m telescope (T. Tuvikene, T. Liimets, T. Eenmäe under supervision of I. Kolka). The analysis of observational data is in progress and the main aim is to investigate the usefulness of light echo for the distance determination to V838 Mon.


Wolf-Rayet (WR) stars

T. Nugis in collaboration with A. Niedzielski and W. Skórzynski (Centre for Astronomy, Torun, Poland) investigated the velocity structure in the outer winds of WR stars and found from the absorption profile differences of strong UV lines and from the observed X-ray fluxes that large velocity differences ($500$- $1000$ km s $^{-1}$) must occur at far distances from the stellar surface ( $r > 1000~R_{\ast}$). The origin of these velocity differences can be explained by two different clumped wind models. In the case of the first model the clump formation process at the stellar surface must be the time-periodical process and the clumps with different initial densities can be accelerated to different terminal velocities, and in the case of the second model the clump formation process is a steady process in time, but the flows from angle-periodically different surface elements (spots) can be accelerated to different terminal velocities.

T. Nugis continued the study of the dependence of WR-star mass loss on metallicity in collaboration with H. Lamers (Utrecht University).

T. Nugis in collaboration with A. Niedzielski, K. Czart, K. Annuk and A. Hirv continued the analysis of near-IR spectra of WR stars.

K. Annuk continued spectroscopic observations of Wolf-Rayet stars using the 1.5 m telescope of Tartu Observatory.


Formation of spectra in atmospheres and winds of hot stars

New algorithms and the corresponding programs for modelling of atmospheres and for calculation of synthetic spectra of hot stars, were improved by A. Sapar and R. Poolamäe. Extensive grid of model atmospheres and corresponding stellar spectra of O, B and A type stars with normal chemical composition (corresponding to the Sun) have been calculated. The iteration process converges rapidly to constant flux throughout the atmosphere. Typical flux constancy of about 0.1-0.2% was obtained with about 10 iterations. The grid of model atmospheres includes all luminosity classes from main sequence to supergiants. The spectral interval in the modelling stretched from 20 to 3000 nanometers, i.e. from the extreme vacuum ultraviolet to far infrared radiation. In the modelling a constant logarithmic spectral step, equivalent to spectral resolution of 30 000, i.e. corresponding to the good quality spectral observations, was used. Approximately 100 000 spectral lines were taken into account in the modelling. Limb darkening of stellar disk was found, which allows by simple algorithms to calculate spectra of rotating stars at given velocity and orientation. Also the radiative accelerations for moving clumps in stellar atmospheres can be calculated, which enables to analyse formation of stellar wind in transition zone between the stellar atmosphere and the stellar wind. In addition to above mentioned FORTRAN software R. Poolamäe wrote a new C++ code for modernizing the computations of stellar model spectra. Elaboration of algorithms and software for finding main parameters of stellar atmospheres (effective temperature, surface gravity and chemical composition) was undertaken based on observed and computed spectra of stars by using the least-square and neural networks methods.

Radiative transfer in stellar winds has been studied by L. Sapar, A. Sapar and R. Poolamäe. Analytical expressions for the frequency redistribution functions of isolated spectral lines in spherical stellar wind have been derived. The case of pure radially prolate Gaussian macroturbulence was studied, assuming the process of scattering to be coherent in the co-moving frame of reference. Thereafter the obtained frequency redistribution function was convolved with the thermal distribution function of atomic particles. The frequency redistribution functions have a complicated angular dependence on the directions and energies of initial and scattered photons. Corresponding software was composed and calculations have been carried out with different frequency redistribution functions. Further the frequency redistribution functions will be used for computation of spectral line profiles in stellar winds. Taking into account the supersonic turbulence enables to compute more adequately the wide slanting slopes in the blue wing of P Cygni type spectral line profiles and corresponding additional emission features in the red wing of the spectral lines.


Elemental diffusion in chemically peculiar stars

A. Sapar and A. Aret continued studies of diffusive segregation of chemical elements and their isotopes in the chemically peculiar (CP) stellar atmospheres, taking into account simultaneously influence of gravitation, radiation pressure and light-induced drift. In modelling the diffusion phenomena it is necessary to take a very short spectral step. From the results of calculations it appeared that the needed spectral step, which avoids computation errors, corresponds to the spectral resolution of 5 000 000. Using the elaborated software the accelerations and diffusion velocities for mercury and its isotopes in the atmospheres of CP stars were found. Studies of joint influence of the light-induced drift and radiative acceleration on the evolutionary segregation of isotopes of heavy chemical elements were carried out, improving computer program SMART. The results enable us to get a picture of formation of vertical distribution of diffusive chemical element in the stellar atmospheres. To describe adequately the segregation, it is necessary to know the isotopic hyperfine splitting of their spectral lines in more detail, on which overlap of the narrow spectral lines of heavy elements depends. These splittings specify first of all the isotope segregation. For adequate modelling of diffusion processes at deep atmospheric layers it is needed to know exact spectral data for multiply ionized atoms. Additional spectral data for Hg III ion have shown, that accelerations in CP stars due to radial pressure and light-induced drift at effective temperatures 10 000-12 000 K were dominating in the deeper layers of atmospheres by this ion. Such a situation also occurs in the studied typical chemically peculiar HgMn stars $\chi$ Lupi (B9.5p + A2Vm) and HR 7775 (B9.5). For the efficiency of the diffusion phenomena it is necessary to treat cross-sections of particle collision processes with high accuracy. The used atomic data were improved by revising the above mentioned data. The computation results show that segregation processes of isotopes of the mercury in atmospheres of CP stars are in accordance with observations, i.e they confirm that the sedimentation of the lighter isotopes and levitation of the heavier isotopes takes place. So, the final stage of evolutionary segregation gives the picture observable in the spectra of the above mentioned stars, where only spectral lines of the heaviest isotope of the studied heavy element are observed. The light-induced drift turns out to be the only physical process, which enables to explain the observed isotope anomalies in the chemically peculiar stellar atmospheres.


Symbiotic stars and related objects

L. Leedjärv and Ph.D. student M. Burmeister continued the spectroscopic monitoring of symbiotic stars on the 1.5 m telescope and the analysis of the spectra. K. Annuk, T. Eenmäe, A. Hirv, and A. Puss participated in these observations, too. The symbiotic star AG Dra reveals several periods of variability, interpretation of which is still problematic. It is almost sure that orbital period of the binary is 550 days, and that variations of the visual brightness take place at about 355-day period (likely, due to pulsations of the red giant). M. Burmeister investigated different photometric time series, using the software package ISDA elaborated by J. Pelt. She found similar photometric periods around 355 days. Analysis of the intensities and equivalent widths of the emission lines (applying the most recent observational data) results in periods of about 380...390 days (depending on the spectral line). Accuracy of the latter periods is lower than that of the photometric one. However, further investigation is needed, in order to find out if such a period could be real, indicating interactions of several physical phenomena (e.g. pulsations of the red giant, irradiation effect, variations of the mass transfer rate etc.). Those studies are underway together with L. Hric from the Astronomical Institute of the Slovak Academy of Sciences.

M. Burmeister and L. Leedjärv started attempts to apply Doppler tomography to the symbiotic star CH Cyg - with a purpose to clarify the nature of its hot component from mapping the velocity distribution in radiating matter, based on the variability of the spectral line profiles.

A. Puss in collaboration with L. Leedjärv has adapted theoretical models of the hot component and accretion disk to the spectral observational data of the binary system VV Cep. Spectral observations of the interacting binary star AX Mon (containing Be-type component) were continued.


Pre-cataclysmic close binaries

V.-V. Pustynski and I. Pustylnik continued their studies of physical processes in irradiated atmospheres of pre-cataclysmic binary systems (PCB) and provided interpretation of the light curves of these systems. Accurate monochromatic albedo values (as a ratio of emergent flux to the incident flux from hot subdwarf companion) have been calculated. It has been found that model monochromatic albedos are of order of 10-15% in the optical region and near infrared, depending on the effective temperatures of the component stars. It has also been indicated that the total emergent fluxes are systematically lower in comparison with the incident flux from the hot companion by at least 20-30%. An exact value depends on the contribution from the light emission in recombinations (reprocessed $L_{\rm c}$ continuum) and can be established only by a careful confrontation of the model light curves with the multicolour observed light curves of PCB. This result is in a good accordance with the previous findings from the model calculations, suggesting that $L_{\rm c}$ continuum flux is only partially spent on ionizing hydrogen whereas a predominant part of the flux is used for heating electron gas and restructuring upper irradiated atmosphere. Similar discrepancy between the emergent and the incident fluxes has been known for many years for Algol type binaries, but its occurence in PCB systems has been indicated for the first time.

I. Pustylnik together with T. Aas, V. Harvig and M. Mars from Tallinn Technical University has studied light-time effect in several semi-detached and contact binaries, based on long time UBVR and H${\alpha}$ photoelectrical observational series obtained in Tallinn Observatory by P. Kalv and his associates between 1967 and 1996 (supplemented by additional measurements made by V. Harvig at Vilnius Observatory high altitude observing station on Mount Maidanak). O-C diagrams of five eclipsing binaries, 44 $\iota$ Boo, AH, CW, EM Cep and RY Gem, have been analysed in detail.

O-C diagram for a semi-detached Algol-type binary RY Gem reveals a trend suggesting the presence of the third invisible companion but the number of available points is not sufficient enough to determine the physical parameters of a putative companion. The "fine structure" of the O-C diagram for a contact binary 44 $\iota$ Boo shows many similarities with another bright and active contact binary VW Cep studied ealier in detail in Tartu Observatory. In both cases this ''fine structure" most likely is caused by the flare activity associated with a more massive component and in the case of 44 $\iota$ Boo it was especially pronounced between 1960 and 1970.


GAIA mission

I. Kolka in collaboration with T. Eenmäe, A. Hirv, T. Tuvikene and M. Kama has completed the first stage of the assessment of photometric systems (BBP and MBP) proposed for the space observatory GAIA. It is shown that in the case of emission line Be, HAeBe and WR stars the current baseline systems are able to separate these peculiar objects from "ordinary" ones. In this context, the importance of broad and medium filter bands embracing the H${\alpha}$ spectral line and of medium bands positioned close to the characteristic emission lines of WR stars has been demonstrated in the Figures 7.1 and 7.2.

Figure: The photometric index calculated by the combination of broad band and medium band H${\alpha}$ fluxes defines the location of emission line stars. The performance of two MBP systems is depicted.

Figure: The suitably selected emission line photometric indices for WR stars (stellar continuum at 467 nm and 585 nm has been interpolated as C467 = 3F386 - 0.67(3F386 - 3F508) and C585 = 3F508 - 0.25(3F508 - 3F891)) are able to distinguish clearly the WN and WC sequences.

The results were presented in October 2004 in Paris at the symposium "The Three Dimensional Universe with GAIA", and will be published in the symposium proceedings by ESA.

V. Malyuto continued classification studies in the framework of the GAIA space project. A commonly-used method of classification - the minimum distance method (MDM) - has been modified and applied to the most recent available GAIA simulated photometric data, the 1X photometric system (proposed in Vilnius) for Gaia-2 configuration with G=18 mag. In the Tartu modification of MDM the weighted metric distances between a programme star (which should be classified) and the templates in the photometric data space are calculated. At first the nearest photometric neighbour (NN) having the shortest distance among templates, is detected. Then some more photometric neighbours are added whose metric distances are within a fixed neighbourhood of the NN. This neighbourhood is defined as the shortest distance + the shortest distance x K, where K is the neighbourhood size and should be determined by trials. The classification results are the astrophysical parameters (APs) for the programme star which are calculated by averaging the appropriate APs for all chosen photometric neighbours with their weights (the weighting factors are inversely proportional to metric distances and are normalized in such a way that their sum equals to 1). Some selected programme stars have been classified (they are among so called scientific targets for which the photometric system will be designed). The classification accuracies are estimated as the r.m.s. differences between the calculated and known APs for each scientific target.

Two different grids of templates have been tried: 1) 20 000 templates, non-regular grid; 2) 116 144 templates, regular grid. The conclusion has been made that only the use of the densest and regular grid of objects (with 116 144 templates) may provide reliable classification. The following classification accuracies are achievable for the solar-type dwarfs: 7000 K in effective temperature, 0.35 in log g, 0.07 in [M/H] and 0.05 in E(B-V).

Sometimes the degenerated cases of the classification algorithm may occur when one or more APs for all chosen photometric neighbours are exactly the same as for the NN. Therefore there is no real interpolation between APs when the APs are averaged in such cases and the classification results may be fictitious. To avoid such a degeneracy, the extended version of MDM has also been realized where the templates are added which are the neighbours in the parametric space for the neighbours of a programme star in the photometric data space. The extended version of MDM provides more realistic results and should be preferable.


Time and frequency analysis of astronomical phenomena

J. Pelt proceeded with the development of programme package for time dependent spectral analysis. He used the package (with collaborators from Tallinn Technical University) to investigate thermal properties of apatites.

With I. Tuominen (Oulu) and J. Brooke (Manchester) J. Pelt checked a published conjecture that sunspot distributions contain century long correlations. Using Monte-Carlo type calculations, it was demonstrated that the correlations are resulting from improper data handling. Some other arguments must be used to prove the true long range correlations.

J. Pelt developed a new method to estimate time delays from unresolved photometry.


Radiative transfer

T. Viik and N.J. McCormick (Washington University, Seattle, USA) described and tested procedures for determining the single-scattering albedo using the measurement of specific intensities within or at the surfaces of homogeneous, optically finite or infinite atmospheres. Unpolarized radiation in an isotropically scattering semi-infinite atmosphere and polarized radiation in an atmosphere that scatters according to the Rayleigh-Cabannes law are considered. According to their numerical experiments the albedo of single scattering can be derived with great accuracy even when the measurements are not so accurate while the determination of other characteristics of the medium is much more complicated. I. Vurm and J. Poutanen (Oulu) extended the method for finding the Compton scattering matrix in isotropic electron gas by D. Nagirner and J. Poutanen to the case when the electron angular distribution is expressible as a power series of the cosines of polar angles. They found the scattering matrix for a second order polynomial expansion. The result could be applicable for studying the synchrotron self-Compton mechanism in a constant magnetic field. As the cooling rate of relativistic electrons is proportional to the square of the sine of the pitch angle with respect to the magnetic field, there is reason to believe that the equilibrium angular distribution of electrons is approximately expressible as a second order polynomial expansion. They also found the matrix for the scattering of electrons on photons for a similar angular distribution of photons. The latter result is relevant only in Klein-Nishina regime, where an electron can lose a significant fraction of its energy in one scattering.


Optical remote sensing of environment in Estonia and Baltic region

Solar UV radiation and atmospheric ozone

Interpretation of the physical effects of the ground-level ultraviolet radiation needs information on its spectral distribution. The most commonly used field instrument is the Brewer spectrometer. It does not cover the full UV region 280-400 nm and costs about 2 million EEK. Taking into account our previous experience of exploitation the minispectrometers, a minispectrometer AvaSpec-256 produced by Avantes company was obtained and adjusted for field measurements adding necessary auxiliary equipment (U. Veismann, K. Eerme, I. Ansko, S. Lätt).

Additionally, a teflon diffuser was made and studied for cosine response. A quartz fiber of 4 m length and 100 $\mu$m diameter connects the diffuser to the spectrometer. An UFS-5 glass optical filter was installed between the diffuser and fiber to reduce the scattered light inside the spectrometer and to guarantee the reliable recording of signal in the whole measured spectral region. For the reliable recording of noise signal the optical interface is automatically covered by a shutter before and after each measurement cycle. Control of the sensitivity for the uniform recording of spectra is realized through the change of integrating time in the interval from 1 to 60 s. In this way a maximum value of the signal approximately 16 000 arbitrary units is realized in each spectrum. For reducing the noise level the spectrometer is installed in a refrigerator and kept at the temperature +7$^{o}$ C. Radiometric response of the system was established using the NIST (National Institute of Standards and Technology, USA) traceable quartz FEL lamp. The measurement process is fully computer-aided through a Linux based program. The auxiliary data on the weather conditions are from the nearby Tartu-Tõravere meteorological station. Experimentally a videocamera is used for recording the current cloud situation. Principal scheme of the measurement complex is presented in Fig. 5.1 on page 50. The control computer of the spectrometer is connected to the computer network of the observatory. Using the server it is possible to access any spectrum in a user-friendly form. It is possible to track the measurements using any computer of the local network and also to have access to the archive of spectra still containing more than 5000 spectra. For submitting the data into the European Database a FLEXSTOR format developed in the EC project EDUCE (European Database for UV Climatology and Evaluation) as well as the program for the automatic quality assurance of spectra including the comparison with model calculations are used. K. Eerme participated with the UV sensor PMA 2200 in the Central-European broadband instrument intercomparison action in Warsaw, Poland 22.05.-26.05.2004.

The data of hourly cloud detection during daytime at the Tartu-Tõravere meteorological station for the period 1957-2003 have been treated to find the monthly mean amounts of cirrus cloud for March-September and to study their variance (K. Eerme). The highest mean value (40 %) was found in April and the lowest (30 %) in July. The results of previous cloud-type notation frequency-based studies using no quantitative measure of cirrus cloud amount exhibit completely different temporal distribution. The smoothed March-September cirrus cloud amount for 1957-2003 manifests a trend of increase and alternation of relatively high and relatively low amounts with a period of approximately 20 years. The relative contribution of clear skies (cirrus amounts less than one tenth) has also decreased.

A comparative study of the reconstructed time-series of the erythemal ultraviolet doses was carried out on the basis of Polish, Czech and Estonian (K. Eerme) data. The contribution of cloudiness was found to be quite similar in all three sites. In all sites lower than average summer doses in the late 1970s as well as the values above the average in the middle 1990s were noticed. The group of remote sensing of atmosphere participates in the COST 726 action "Long-term changes and climatology of UV radiation over Europe" planned for 2004-2008. The aim of action is to reconstruct at first the erythemally weighted and afterwards also otherwise weighted daily and integrated doses over longer intervals back to 1950. Still 19 countries have joined the action.


Climate studies

Spectral measurements of solar radiation by the automatic sunphotometer of Aerosol Robotic Network (AERONET) started at Tõravere in June 2002. In order to examine the spectral atmospheric aerosol optical thickness AOT retrospectively during a prolonged period when spectral measurements were not available, V. Russak has used a model for transition from broadband irradiance to spectral aerosol optical thickness at 500 nm, elaborated in Moscow University (Fig. 8.1). This method was chosen as it provided high correlation (R = 0.991) between the spectral AOT values measured by the AERONET photometer and calculated by the model at Tõravere in 2002-2003 (405 cases were analysed). A comparison of time series of spectral and broadband AOT at Tõravere during 1951-2003 reveals a close similarity, whereas the AOT values at 500 nm exceed their broadband values by about 2-3 times.

It is characteristic that long-term changes in the annual mean values of aerosol optical thickness at 500 nm were more rapid than in the broadband values (increase during the first three decades and sharp decrease since the 1980s). This indicates that changes have occurred not only in the amount of aerosol, but also in its optical parameters, physical properties and chemical composition in Tartu and Tõravere during 1951-2003.

Figure: Time series of annual mean broadband and spectral (500 nm) atmospheric aerosol optical thicknesses AOT at Tõravere in 1951-2003.


Remote sensing of vegetation

A. Kuusk and T. Nilson took part in the radiation transfer model intercomparison (RAMI) with the forest radiative transfer model FRT. Several modules of this model are based on analytical solutions of the radiative transfer problem, consequently, the model is significantly less computer-intensive than other participating models. The results of simulations agreed well with other models in the visible spectral domain. There was more scattering of results in the near infrared spectral domain, however, this is valid for other models as well.

T. Nilson and A. Kuusk in collaboration with P. Stenberg and M. Rautiainen (University of Helsinki) studied the role of crown shape in the reflectance of conifer stands. In the interpretation of satellite measurements crown shape should be accounted for.

T. Nilson analysed together with M. Rautiainen and P. Stenberg (University of Helsinki) the results of canopy cover measurements in pine-dominated forests in Suonenjoki (Finland) region. The canopy cover estimates by the two methods applied (Cajanus tube and LAI-2000 plant canopy analyser) were found to be in a good agreement. Both of the methods required approximately 250 measurement points for canopy closure estimates to become relatively stable.

A. Kuusk and M. Mõttus measured radiation fields with high spatial resolution in red (680 nm) and near infrared (800 nm) spectral channels in the plantation of alder at Tartu Observatory, Tõravere.

Reflectance spectra measurements by means of the new spectrometer FieldSpec Pro were carried out by T. Nilson, together with O. Kull and P. Mänd (Tartu University) in a shrubland in Garraf, Spain within the framework of EU project VULCAN (Vulnerability assessment of shrubland ecosystems in Europe under climatic changes). T. Nilson processed and analysed the measured reflectance spectra. Kuusk-Nilson forest reflectance model was applied to simulate the shortwave (400-1100 nm) reflectance spectra of the shrubland. As measured inputs, the data on the dominating species (plant density, dimensions, leaf mass per area, leaf chlorophyll content) were used. A reasonable fit was obtained between the simulated and measured spectra.

A. Kuusk in collaboration with L. Eklundh and P. Jönsson (Lund University, Sweden) applied the forest reflectance model FRT developed at Tartu Observatory by A. Kuusk and T. Nilson for the normalization of MODIS spectroradiometer data over forests in the whole Sweden. The data measured at various Sun zenith angles and in different seasons are reduced with the reflectance model to a single uniform measurement situation.

U. Peterson together with J. Liira and K. Püssa from the Institute of Botany and Ecology, Tartu University estimated the effect of factors influencing the determination of forest boundaries on medium resolution satellite images. It was hypothesized that shadows cast by trees of forest edges on the bright snow of the surrounding open area make north- or northwest-facing edges less sharp than edges facing other directions. The results of the study show that there is no significant shadow effect, as the reflectance at forest edges exposed in different azimuthal directions does not differ on Landsat Thematic Mapper (TM) winter images under plain snow cover conditions. From the result, it follows that a global threshold can be applied in image classification of winter images if forest is the target class.

U. Peterson together with J. Liira and K. Püssa tested the dependence of reflectance in Landsat TM spectral bands on forest site type, gap size and forest age within a time range of the first ten years following clear-cut logging. Landsat TM images that correspond seasonally to the beginning of the growing period, peak summer and late winter were used.

A. Kuusk and M. Paas (M.Sc. student at Tartu University) studied light scattering in the foreoptics of the CCD-radiometer of hemispherical field-of-view. A correction algorithm which is based on the Wiener filtering on the sphere was developed.

M. Lang tested the performance of Kuusk-Nilson forest reflectance model using as input the forest inventory data for a set of permanent forest growth sample plots. The sample plots have been established due to the initiative of Prof. A. Kiviste (Estonian Agricultural University). The simulated and Landsat TM image-derived reflectances for these sample plots were compared. The agreement was rather poor in most of the spectral bands. The main sources of errors that were pointed out are: problems in processing and atmospheric correction of the satellite image, allometric regression functions to estimate variables like tree leaf mass, crown radius etc. from the forest database, small dimensions of sample plots compared to the pixel size of the image and errors in the geographical location of the plots. To get a better fit, the methods concerning all these aspects need to be improved.

M. Pehk elaborated a spectrometer for field measurements of vegetation canopies in the wavelength interval from 800 to 1700 nm. The optical part of the spectrometer consists of a classical autocollimating scheme with relative aperture 1:5.7. A diffraction grating 800 l/mm, $\lambda_{\rm max}$ = 1300 nm is used for dispersion and InGaAs G5125-10 photodiode as a light detector. The scanning of spectrum is realized by a sinus mechanism with a step of 0.2 nm. The field-of-view is formed by a set of 5-stage field diaphragms. A special case contains the control electronics, data-processing system (24-bit ADC M201, micro controller AVR-H128B (ATMEGA 128)), notebook computer and NiMH battery. The spectrometer went through a preliminary testing in field conditions. The software elaboration and debugging is being made by J. Kuusk (M.Sc. student of Tartu University).


Remote sensing of water bodies

A. Reinart and O. Okulov started archiving satellite images and collection of in situ data to apply remote sensing methods for Estonian water bodies. In collaboration with J. Ehn, M. Granskog (Helsinki University) and D. Pierson (Uppsala University) already existing data on ice and lake remote sensing spectra measured in Estonian water bodies were analysed. Also time series of atmospheric transparency and aerosol optical thickness were compared with similar data in Baltic Sea region. A. Reinart and B. Paavel (M.Sc. student at Tartu University) measured reflectance spectra and other optical properties of small Estonian lakes and Lake Peipsi. O. Okulov arranged regular sampling and measurements of water temperature in Peipsi for the calibration of satellite images.


Remote sensing of the atmosphere

O. Kärner together with K.-G. Karlsson (Swedish Meteorological and Hydrological Institute) analysed the CM-SAF cloud detection algorithm's performance in the Arctic summer conditions. Due to its use of both AVHRR 5-channel data and data on temperature and humidity retrieved from a numerical weather prediction model, the method can be modified by adding a feedback scheme. The task is not finished yet, but one manuscript has been submitted for publication.


Energy forest

In 2004, our attention was mainly concentrated on the grey alder (Alnus incana) plantation at Tõravere (M. Sulev, M. Mõttus). The fourth growing year was favourable for the plantation, at the end of summer, the maximum height of trees exceeded 6 m. The structure of the plantation resembles that of a forest, the canopy has closed. At the same time, prevailingly rainy and overcast weather prevented us from carrying out the planned amount of field work. The structure of the plantation resembled that of a natural forest while the physical dimensions of the trees still allowed for accurate biometrical measurements.

However, during the following years, the density of the plantation will start to considerably exceed that of natural forests, and to reduce it, selective cutting of every second tree is planned. Two main tasks were planned for 2004: first, the study of the radiation regime and its spatial and temporal variability using already established methods, and second, the creation of physically-based radiative transfer models together with measuring the necessary input parameters, both biometrical and optical, and also the comparison of measurement and modelling results. In the framework of the first task, photosynthetically active radiation and the components of the radiation balance were measured at five heights inside the alder canopy and also above it. Biometrical measurements carried out in parallel with radiation measurements were used to estimate the growth dynamics of the trees, the vertical distribution of leaf area index and its temporal variation during the growth period. Preliminary results indicate that alder is more transparent to solar radiation than willow. As the trees grow, the leaves on lower layers fall and a considerable part of the foliage is concentrated in the upper third of the canopy. Accordingly, most of the incident radiation is absorbed in this region. To estimate the productivity of grey alder as a possible renewable energy source, the above-ground biomass productivity was estimated.

The creation of physically-based radiative transfer models sets forth new requirements for determining the input parameters. Detailed and specific measurements are needed to determine a ''statistically typical" tree, and also to describe the spectral properties of phytoelements. To test the models, angular intensities and spectral characteristics of radiation have to be measured inside and above the canopy. As the alder canopy is much more inhomogeneous than that of willow (our previous research subject), the requirements for biometrical measurements were more strict. The natural origin of plants, compared with a single willow clone that was used previously, and also the somewhat varying age of trees add more difficulty to the mathematical description of the forest. To give a detailed description of the foliage, an extensive measurement campaign was carried out by breaking the stems and branches into segments that had formed during the growing seasons of 2000-2004, measuring the length, width and area of leaves, and determining the inclination angles of these phytoelements. The basic characteristics of the trees, height and diameter at 55 cm above ground, were measured repeatedly during the summer. Using this data, a model of a ''statistically average" plant was constructed to describe the tree as a fractal structure using so called L-systems. The constructed ''average"  tree includes not only the average parameters, but also their statistical variations as approximated by an appropriate statistical distribution. This type of computer reconstruction of the forest allows for a reasonable estimation of the various characteristics of the alder canopy at the period of radiation measurements in August 2004. In cooperation with M. Lang and A. Kuusk, the following radiation measurements were carried out on cloudless days: the angular distribution of reflected radiation was measured with a CCD radiometer; canopy transmittance was measured with a canopy analyser LAI 2000 (LI-COR Inc.); the spectral distribution of below-canopy radiation was registered with the FieldSpec (ASD Inc.) spectrometer. The results of these measurements may be compared with those predicted by forest radiative transfer models to improve our understanding of the effect of canopy structure on the transmittance and reflectance of natural plant canopies. The reflecting and transmitting phase functions of alder leaves were measured with a spectrogoniometer in a laboratory in the blue, green, red and infrared spectral regions. Also, the possibility to use the FieldSpec spectrometer for measuring radiation reflected and transmitted by a leaf was tested both with an integrating sphere and by using narrow view angles.


Publications

Papers in scientific journals and books

Astronomy

Jaaniste J., Einasto M., Einasto J.: Deep Slices and the Supercluster-Void Network. Astrophys. Space Science 290, 187-193, 2004.

Kaljuvee T., Pelt J., Radin M.: TG-FTIR Study of Gaseous Compounds Evolved at Thermooxidation of Oil Shale. Journal of Thermal Analysis and Calorimetry 78, 399-414, 2004.

Karitskaya E.A., Bondar A.V., Bochkarev N.G., Galazutdinov G.A., Musaev F.A., Sapar A.A.: The Optical High-Resolution Spectroscopy as a Method of X-ray Binary Cyg X-1 Investigation. Odessa Astronomical Publications 16, 33-36, 2003.

Kipper T., Klochkova V.G., Annuk K., Hirv A., Kolka I., Leedjärv L., Puss A., Škoda P., Slechta M.: The Peculiar Variable V838 Monocerotis. Astron. Astrophys. 416, 1107-1115, 2004.

Kipper T.: Carbon Stars in the UVES Paranal Observatory Project. Baltic Astronomy 13, 573-580, 2004.

Kubát J., Krticka J., Pustylnik I.: Radiation Induced Coronal Wind in Late B Stars. New Astronomy 9, 215-224, 2004.

Leedjärv L.: High-Velocity Jets from Symbiotic Stars and Other Astrophysical Systems. Baltic Astronomy 13, 109-115, 2004.

Leedjärv L., Burmeister M., Miko\lajewski M., Puss A., Annuk K., Ga\lan C.: Emission Lines in the Spectrum of the Symbiotic Star AG Draconis from 1997 to 2003. Astron. Astrophys. 415, 273-282, 2004.

Niedzielski A., Nugis T., Skórzynski W.: Kinematical Structure of Wolf-Rayet Winds. II. Internal Velocity Scatter in WN Stars. Acta Astronomica 54, 405-427, 2004.

Pustylnik I.: Zdenek Kopal's Binary Star Legacy International Conference. Astronomical and Astrophysical Transactions 23, 441-442, 2004.

Pustynski V.-V., Pustylnik I.: Modelling the Irradiated Atmospheres of Unevolved Companions in Pre-Cataclysmic Binaries. Baltic Astronomy 13, 122-127, 2004.

Stoica R. S., Martínez V.J., Mateu J., Saar E.: Detection of Cosmic Filaments. UJI Technical Report 75, 1-21, 2004.

Tõnsuaadu K., Borissova M., Bender V., Pelt J.: Thermal Reactions in Synthetic Apatite - Ammonium Sulfate Mixture. Phosphorus, Sulfur, Silicon and the Related Elements 179, 2395-2407, 2004.



Geophysics

Eerme K., Veismann U., \fbox{Koppel Rutt}: Comparison of Ground-Level-Measured and Satellite-Derived Erythemal Ultraviolet Doses in Estonia. Proc. Estonian Acad. Sci. Phys. Math. 52, 221-235, 2003.

Eerme K.: Changes in Spring-Summer Cirrus Cloud Amount Over Estonia, 1958-2003. Int. J. Climatol. 24, 1543-1549, 2004.

Krzyscin J. W., Eerme K., Janouch M.: Long-Term Variations of the UV-B Radiation Over Central Europe as Derived From the Reconstructed UV Time-Series. Annales Geophysicae 22, 1473-1485, 2004.

Kuusk A:. Peegeldusmudelid taimkatte kaugseires. Publ. Inst. Geographici Universitatis Tartuensis 95, 45-48, 2004.

Kuusk A., Lang M., Nilson T.: Simulation of the Reflectance of Ground Vegetation in Sub-Boreal Forests. Agricultural and Forest Meteorology 126, 33-46, 2004.

Kutser T., Pierson D.C., Tranvik L., Reinart A., Sobek S.: Lahustunud orgaanilise aine määramisest järvedes kaugseire meetoditega. Publ. Inst. Geographici Universitatis Tartuensis 95, 125-143, 2004.

Kärner O.: Lävemetoodika alused pilvisust kirjeldavate suuruste määramiseks satelliidiandmetest. Publ. Inst. Geographici Universitatis Tartuensis 95, 20-30, 2004.

Lang M., Uiga R., Lükk T., Anniste J.: Raiete kaardistamine kosmosepiltidelt. Publ. Inst. Geographici Universitatis Tartuensis 95, 64-76, 2004.

Liang S.: Quantitative Remote Sensing of Land Surfaces. Wiley, 2004. 534 pp. The forest reflectance model FRT (Kuusk and Nilson, 2000) and the two-layer homogeneous CR model ACRM (Kuusk, 2001) are included on the CD-ROM.

Lükk T.: KNN-meetodi rakendamine metsade takseerparameetrite hindamisel ja kaardistamisel. Publ. Inst. Geographici Universitatis Tartuensis 95, 77-89, 2004.

Nilson T.: Kaugseire rakendusvõimalusi. Publ. Inst. Geographici Universitatis Tartuensis 95, 7-19, 2004.

Nilson T., Kuusk A.: Improved Algorithm for Estimating Canopy Indices from Gap Fraction Data in Forest Canopies. Agricultural and Forest Meteorology 124, 157-169, 2004.

Peterson U.: Mets ja raiesmikud Landsat TM viieteistkümne-aastase aegrea satelliidipiltidel. Publ. Inst. Geographici Universitatis Tartuensis 95, 49-63, 2004.

Peterson U., Püssa K., Liira J.: Issues Related to Delineation of Forest Boundaries on Landsat TM Winter Images. International Journal of Remote Sensing 25, 5617-5628, 2004.

Pinty B., Widlowski J.-L., Taberner M., Gobron N., Verstraete M. M., Disney M., Gascon F., Gastellu J.-P., Jiang L., Kuusk A., Lewis P., Li X., Ni-Meister W., Nilson T., North P., Qin W., Su L., Tang S., Thompson R., Verhoef W., Wang H., Wang J., Yan G., Zang H.: Radiation Transfer Model Intercomparison (RAMI) Exercise: Results from the Second Phase. J. Geophys. Res. 109, D06210 10.1029/2003JD004252, 2004.

Rautiainen M., Stenberg P., Nilson T., Kuusk A.: The Effect of Crown Shape on the Reflectance of Coniferous Stands. Remote Sensing of Environment 89, 41-52, 2004.

Reinart A., Paavel B., Tuvikene L.: Effect of Coloured Dissolved Organic Matter on the Attenuation of Photosynthetically Active Radiation in Lake Peipsi. Proc. Estonian Acad. Sci. Biol. Ecol. 53, 88-105, 2004.

Reinart A., Paavel B., Pierson D., Strömbeck N.: Inherent and Apparent Optical Properties of Lake Peipsi, Estonia. Boreal Environment Res. 9, 429-445, 2004.

Reinart A.T., Reinart A.E., Pierson D.C.: SeaWiFS ja MODIS sensorite atmosfäärikorrektsiooni rakendatavusest suurte järvede korral. Publ. Inst. Geographici Universitatis Tartuensis 95, 169-184, 2004.

Teral H., Ohvril H., Okulov O., Russak V., Reinart A.: Atmosfääri aerosoolse optilise paksuse arvutamine päikese integraalsest otsekiirgusest. Publ. Inst. Geographici Universitatis Tartuensis 95, 31-44, 2004.


Conference papers

Astronomy

Kubát J., Krticka J., Pustylnik I., Votruba V.: The Possibility of a Disk Formation Around Late B Stars. In: Stellar Rotation. Proc. IAU Symposium No. 215, eds. A. Maeder and P. Eenens, 49-50, 2004.

Leedjärv L., Tomov T., Miko\lajewski M., Burmeister M.: CH Cygni and Other Symbiotic Stars with Low Luminosity Hot Components. In: Compact Binaries in the Galaxy and Beyond. Proc. IAU Colloq. No. 194, eds. G. Tovmassian and E. Sion, Revista Mexicana de Astronomía y Astrofísica, Ser. de Conferencias 20, 223, 2004.

Pustylnik I.: Petzval Astrograf of Tartu Observatory. In: Short Contributions Presented at the Annual Scientific Meeting of the Astronomische Gesellschaft and the Czech Astronomical Society in Prague, September 20-25, 2004. Astron. Nachr. Supplement 325, 72, 2004.

Tamm A.: Structure of Visual and Dark Matter Components of Spiral Galaxies at $z\sim1$. In: Proc. of ''Baryons in Dark Matter Haloes'', Novigrad, Croatia, October 5-9, 2004, eds. R. Dettmar, U. Klein and P. Salucci, 92, 2004.

Traat P.: Evolution of Stellar Populations in the Case of Gas Accretion/Outflow. In: The Interplay among Black Holes, Stars and ISM in Galactic Nuclei. IAU Symposium No. 222, held in Gramado, Brasil, March 1-5, 2004. Abstracts. 1 page, 2004.

Tõnsuaadu K., Pelt J., Borissova M.: Monitoring of the Evolved Gases by FTIR Spectroscopy in Apatite - Ammonium Sulfate Thermal Reactions. In: 13th International Congress on Thermal Analysis and Calorimetry, Book of Abstracts, Chia Laguna, September 12-19, 357, 2004

Viik T., McCormick N.J.: Quadratic Integrals in Inverse Problems with Multiple Scattering. In: Photopolarimetry in Remote Sensing, eds. G. Videen et al., 125-136, 2004.


Geophysics

Eerme K.: Changes in Spring-Summer Cirrus Cloud Amount and Other Cloudiness Related Characteristics Over Estonia (1958-2002). In: Extended Abstracts of the Workshop ''Ozone and UV Radiation over Central Europe", (20-22 October 2003, Jachranka, Poland), 123-126, 2004.

Jakobson E., Ohvril H., Okulov O., Laulainen N.: Relationships Between Precipitable Water and Geographical Latitude in the Baltic Region. In: Fourth Study Conference on BALTEX (24-28 May 2004, Gudhjem, Bornholm, Denmark). Conference proceedings, ed. J. Meywerk, 53-54, 2004.

Lang M., Lükk T.: Estimation of the Forest Parameters From Satellite Images Using Forest Reflectance Model. In: Proceedings of a Conference ''Research for Rural Development", Jelgava, Latvia, Latvian University of Agriculture, 173-177, 2004.

Reinart A., Pierson D., Strömbeck N., Land P., Reinhold M.: A Satellite Based Water Quality Monitoring System for Lakes Vänern and Vättern, Sweden. Proceedings of Ocean Optics XVII, Fremantle, 2004 (CD-ROM).

Russak V., Teral H., Ohvril H.: Trends in Atmospheric Aerosol Loading in Estonia During the Period 1951-2003. CD: Fourth Annual Meeting of the European Meteorological Society. Part and Partner: 5th European Conference on Applied Climatology (ECAC), Nice, France, 26-30 September. 2004.

Teral H., Ohvril H., Okulov O., Russak V., Reinart A., Laulainen N.: Spectral Aerosol Optical Thickness from Solar Broadband Direct Irradiance - Summer 2002, Tõravere, Estonia. In: Abstracts of the European Aerosol Conference 2004 (6-10 September 2004, Budapest, Hungary), J. Aerosol Science, S547-548, 2004.

Veismann U.: UV Sensors Based on the Solar Blind Phototubes. In: Extended Abstracts of the Workshop ''Ozone and UV Radiation over Central Europe", (20-22 October 2003, Jachranka, Poland), 143-145, 2004.


Popular Articles

The articles are in Estonian if not indicated otherwise.

Astronomy

Einasto J., Einasto M.: Astronomy in the beginning of the new millennium. Estonia Yearbook, 275-290, 2004 (In English).
Einasto J.: Teadus Tartu Observatooriumis. Tähetorni Kalender 2005, 43-55, 2004.
Einasto M.: GOODSi projekt. Tähetorni Kalender 2005, 71-81, 2004.
Haud U.: Kummaline raadioastronoomia. Horisont 6, 29-33, 2004.
Haud U.: Orion. http://www.aai.ee/~urmas/ast/orion.html.
Haud U.: GOODS in FIR and Radio. http://www.aai.ee/~urmas/GOODS/ (In English).
Jõeveer M.: Muistne taevakaart kivil? Astronoomi kommentaar. Eesti Loodus 8, 22-23, 2004.
Jõeveer M.: Kas Päikesesüsteemi avastamine jätkub? Horisont 3, 56-57, 2004.
Jõeveer M.: Varase Universumi sündmuste jälile. Horisont 5, 31-35, 2004.
Jõeveer M.: Miks on Maa ümmargune? http://www.loodusajakiri.ee/eesti_loodus/uudistaja2.html.
Jõeveer M.: Tuhkvalgusest ja Maa muutuvast heledusest. Tähetorni Kalender 2005, 86-88, 2004.
Jõeveer M.: Akadeemik Jaan Einasto juubel. Tähetorni Kalender 2005, 94-99, 2004.
Kipper T.: Kompamine kardina tagant. Horisont 4, 30-35, 2004.
Leedjärv L.: Mitmevärviline Universum. Horisont 1, 26-30, 2004.
Leedjärv L.: Läbi kitsa pilu paistab palju. Horisont 2, 33-37, 2004.
Leedjärv L.: Optilise akna avamisviisidest. Horisont 3, 32-36, 2004.
Leedjärv L.: Eestlaste uued küünlad. Postimees, 07.09.2004.
Pelt. J.: Kuidas ma arvutasin maailma vanust. Tähetorni Kalender 2005, 64-70, 2004.
Saar E.: Supernoovad ja tumeenergia. Tähetorni Kalender 2005, 82-85, 2004.
Sapar A.: Maa põlvnemine ja sünd. Maa Universumis. Möödanik, tänapäev, tulevik, koostanud H. Nestor, A. Raukas ja R. Veskimäe. Tallinn, 11-19, 2004.
Sapar A.: In memoriam. Leo Sorgsepp (1.V 1928-1.IX 2003). Tähetorni Kalender 2005, 122-124, 2004.
Tago E.: Astronoomia 2003. Vaatleja 1, 2004.
Tago E.: Kaugusrekordi jaht Universumi piiril. Vaatleja 2, 2004.
Tago E.: Amatööri(de) suur tähetund: McNeili udu avastamine. Vaatleja 2, 2004.
Tago E.: Kosmoseteleskoop pildistas esmakordselt eksoplaneeti. Vaatleja 3, 2004.
Tago E.: Galaktikad ja mustad augud arenevad käsikäes. Vaatleja 3, 2004.
Tago E.: Mis kuumutas taas üles Universumi? Vaatleja 5, 2004.
Tago E.: Tycho Brahe supernoova 432 aastat hiljem. Vaatleja 6, 2004.
Traat P.: Kääbusgalaktika 1Zw18 - noorim teadaolevaist? Vaatleja 6, 2004.
Traat P.: Tähtede ja galaktikate vanusest. Vaatleja 6, 2004.
Viik T.: Tõravere Eesti kultuuriloos. Horisont 6, 40-46, 2004.
Viik T.: Tõravere Eesti kultuuriloos. Nõo valla leht 9, 10, 11, 2004.
Viik T.: Thomas Clausen - karjapoisist professoriks. Tähetorni Kalender 2005, 100-108, 2004.
Vurm I.: Lühiülevaade NATO ASI suvekoolist ''Neutrontähtede elektromagnetiline spekter". Tähetorni Kalender 2005, 89-93, 2004.


Geophysics

Kallis A.: Kogumik ''Ümber Euroopa. Kes? Mis? Kus?" (Üks koostajaid). Tänapäev. Tallinn 2004, 496 lk.
Kallis A.: Ilma Harju keskmine. Maaleht, 29.01.2004.
Kallis A.: Viisakalt valge näärikuu. Maaleht, 05.02.2004.
Kallis A.: Lumine jaanuar hoidis küttearved madalal. Postimees, 10.02.2004.
Kallis A.: Maraton kaotas ilmale. Maaleht, 12.02.2004.
Kallis A.: Paljupäevaline vastel. SL Õhtuleht, 28.02.2004.
Kallis A.: Ilm pakkus käkke ja kinke. Maaleht, 04.03.2004.
Kallis A.: Talid pole õed. Postimees, 09.03.2004.
Kallis A.: Ilmategijate pidupäev. Maaleht, 18.03.2004.
Kallis A.: Muna püsti! SL Õhtuleht, 20.03.2004.
Kallis A.: Ilmataadi vingerpussid. Maaleht, 01.04.2004.
Kallis A.: Ohtlik Marss ja ohutu vihmavari. SL Õhtuleht, 03.04.2004.
Kallis A.: Märts ei toonudki seekord kevadet kaasa. Postimees, 07.04.2004.
Kallis A.: Märts tegi ilmas tükke. Maaleht, 08.04.2004.
Kallis A.: Jälle on õhus äikest ehk kas iga välgulöök tapab? SL Õhtuleht, 30.04.2004.
Kallis A.: Aprill saatis Eesti tolmusena Euroopasse. Postimees, 05.05.2004.
Kallis A.: Jälle kuivast kõrini! Maaleht, 06.05.2004.
Kallis A.: Ilmajaam on iseseisvuse tunnus. Maaleht, 20.05.2004.
Kallis A.: Milline suveilm tuleb? SL Õhtuleht, 26.05.2004.
Kallis A.: Pirts mai. Maaleht, 03.06.2004.
Kallis A.: Mai oli ajuti frigiidne. Postimees, 08.06.2004.
Kallis A.: Siiri Oviir varjutas Veenuse! SL Õhtuleht, 12.06.2004.
Kallis A.: Soodsalt müüa kõrgrõhuhari. Maaleht, 22.06.2004.
Kallis A.: Eestimaale lasti vesi juunikuus peale! Postimees, 06.07.2004.
Kallis A.: Pikse litaania ehk Las kallab! SL Õhtuleht, 02.07.2004.
Kallis A.: Ilmarindel muutuseta. Maaleht, 08.07.2004.
Kallis A.: Vajame äärmiselt täpset prognoosi. Maaleht, 29.07.2004.
Kallis A.: Pilves olemisest mitme nurga alt. SL Õhtuleht, 30.07.2004.
Kallis A.: Juuli uputas linnas ja maal. Maaleht, 05.08.2004.
Kallis A.: Kas meie ilmaennustusi saab usaldada? Eesti Päevaleht, 07.08.2004.
Kallis A.: Juuli ei jäänud vihmadega jaanist maha. Postimees, 10.08.2004.
Kallis A.: Kiiremini, kaugemale, kuumemini! SL Õhtuleht, 14.08.2004.
Kallis A.: Ostan päikesepleki eemaldaja. Maaleht, 19.08.2004.
Kallis A.: Ülemiste vanakesel on tänavu nimeks August! Postimees, 07.09.2004.
Kallis A.: August keskmiselt märg. Maaleht, 09.09.2004.
Kallis A.: Kuidas kohtunik ilma tegi. Maaleht, 16.09.2004.
Kallis A.: Kumb on hirmsam - põud või uputus? SL Õhtuleht, 18.09.2004.
Kallis A.: Värisegu maa su jalge all! SL Õhtuleht, 23.09.2004.
Kallis A.: Seenetav september. Maaleht, 07.10.2004.
Kallis A.: Antropogeenne kliimamuutus Pärnus. Postimees, 12.10.2004.
Kallis A.: Mihkel oli tänavu tormakas ja märg, kuid soe. Postimees, 12.10.2004.
Kallis A.: Lahkus trombikütt. Maaleht, 21.10.2004.
Kallis A.: Vesine viinakuu. Maaleht, 04.11.2004.
Kallis A.: Soojavõitu viinakuu vananaistesuve siiski ei toonud. Postimees, 09.11.2004.
Kallis A.: Kui sõitsid ilmarongid. Maaleht, 25.11.2004.
Kallis A.: Pimedusega kaamose vastu. SL Õhtuleht, 27.11.2004.
Kallis A.: Lapsed õue - tali tuli! Maaleht, 02.12.2004.
Kallis A.: Talvekuu tõi lumetormi ja liiklusummikud. Postimees, 07.12.2004.
Kallis A.: Maailmarekord head ei too. Maaleht, 16.12.2004.
Kallis A.: Kui meri väriseb. SL Õhtuleht, 29.12.2004.
Kallis A.: In memoriam. Heino Tooming. Tähetorni Kalender 2005, 125-126, 2004.
Kallis A.: Ilm. Aastaraamat Kes? Mis? Kus? 2005, Tänapäev, 411-422, 2004.
Kuusk A.: Triibuline vaip öötaevas. Maaleht, 28.10.2004.
Veismann U.: Päikese ultraviolettkiirguse spektroradiomeetria. Tähetorni Kalender 2005, 56-63, 2004.
Veismann U.: Eesti ja NSV Liidu kosmoseprojektid. Akadeemia 8, 1719-1732, 2004.


Grant Reports

Russak V.: Study of Variable Components of the Atmosphere and Their Variability by Optical Sounding Method. Grant of the Estonian Science Foundation No 4140, Final Report. Tartu Observatory, 44 pp, 2004.
Peterson U.: Mapping Afforestation of Abandoned Agricultural Land in Estonia and its Neighbouring Countries with Remote Sensing Data. Grant of the Estonian Science Foundation No 4698, Final Report. Tartu Observatory, 53 pp, 2004.


Preprints

Andernach H., Tago E., Einasto M., Einasto J., Jaaniste J.: Redshifts and Distribution of ACO Clusters of Galaxies. [astro-ph/0407097].

Andernach H., Plionis M., Lopez Cruz O., Tago E., Basilakos S.: The Abell Cluster M/L and the Value of $\Omega_m$ from a Sample of $1600$ Velocity Dispersions. [astro-ph/0407098].

Einasto J., Tago E., Einasto M., Saar E., Suhhonenko I., Heinämäki P., Hütsi G.: Toward Understanding Environmental Effects in SDSS Clusters. [astro-ph/0411235].

Einasto J., Tago E., Einasto M., Saar E.: Clusters and Superclusters in the Sloan Survey. [astro-ph/0408463].

Einasto J.: Dark Matter: Early Considerations. [astro-ph/0401341].

Einasto J.: Clusters and Superclusters in the Sloan and Las Campanas Surveys. [astro-ph/0401342].

Einasto M., Suhhonenko I., Heinämäki P., Einasto J., Saar E.: Environmental Enhancement of DM Haloes. [astro-ph/0411529].

Jones B.J.T., Martínez V.J., Saar E., Trimble V.: Scaling Laws in the Distribution of Galaxies. [astro-ph/0406086].

Pelt J., Tuominen I., Brooke J.: Century Scale Persistence in Longitude Distribution: In the Sun and in Silico. [astro-ph/0410649].

Starck J.-L., Martínez V.J., Donoho D. L., Levi O., Querre P., Saar E.: Analysis of the Spatial Distribution of Galaxies by Multiscale Methods. [astro-ph/0406425].

Stoica R.S., Martínez V.J., Mateu J., Saar E.: Detection of Cosmic Filaments Using the Candy Model. [astro-ph/0405370].

Tamm A., Tenjes P.: Structure of Visible and Dark Matter Components in Spiral Galaxies at Redshifts $z$=0.5-0.9. [astro-ph/0412208].

Tamm A., Tenjes P.: Structure of Visible and Dark Matter Components of Spiral Galaxies at $z\sim 0.9$. [astro-ph/0412322].

Traat P.: Spectral Evolution of and Radiation Energy Generation by Coeval Stellar Populations with Different Initial Composition and Chemical Enrichment. [astro-ph/0412708].

Vennik J., Hopp U.: A Multiwavelength Study of the Galaxy Content and Environmental Effects in the Dense Group of Galaxies around IC 65. [astro-ph/0409632].

Vennik J., Hopp U.: Photometric Study of the Galaxies in the Area of the IC 65 Group of Galaxies. [ftp://jupiter.aai.ee/pub/users/vennik/IC65group.ps.gz].


Meetings

Astronomy

A Winter School ''The Origin of Galaxies" (Jerusalem, Israel, 30.12.2003-08.01.2004) - I. Suhhonenko, A. Tamm.

XXXIV Eesti Füüsika päevad (Tartu, Estonia, 13.02.-14.02.2004) - T. Viik.

Viik T.: Ruutintegraalid kiirguslevi pöördülesannetes (oral presentation).

Nearby Large-Scale Structures and the Zone of Avoidance (Cape Town, South Africa, 28.03.-02.04.2004) - J. Einasto.

Einasto J., Tago E., Einasto M., Saar E.: Clusters and Superclusters in the Sloan Survey (oral presentation).

Conference ''Zdenek Kopal's Binary Star Legacy" (Litomysl, Czech Republic, 30.03.-04.04.2004) - I. Pustylnik.

Pustylnik I.: New Package of Computer Codes for Analysing Light Curves of Eclipsing Precataclysmic Binaries (oral presentation).

Pustylnik I.: Resolving the Algol Paradox and Kopal's Classification of Close Binaries with Evolutionary Implications (oral presentation).

Pustylnik I.: BM Cas - a Long Period Eclipsing Binary with a Supergiant and Common Envelope (poster).

Nordic Meeting on High Energy Astrophysics (Saariselkä, Finland, 05.04.-08.04.2004) - I. Vurm.

Tartu-Turku Workshop ''GOODS Project" (Tõravere, Estonia, 20.04.-21.04.2004) - J. Einasto, M. Einasto, M. Gramann, M. Jõeveer, E. Saar, I. Suhhonenko, U. Haud, E. Tago, P. Tenjes, P. Traat, J. Vennik.

Jõeveer M.: ALMA, JCMT ja teised (oral presentation).

Saar E.: GOODS ja aktiivsed galaktikad (oral presentation).

Haud U.: GOODS kauges infrapunases ja raadios (oral presentation).

Tago E.: Röntgenvaatlused GOODS-is (oral presentation).

Tenjes P.: HST ja VLT vaatlused GOODS projektis (oral presentation).

Einasto M.: Galaktikate spektritest (oral presentation).

Traat P.: SIRTF ja galaktikate evolutsioon (oral presentation).

Vennik J.: Kääbusgalaktikad süvavalimites (oral presentation).

Gramann M.: Tume aine ja galaktikad (oral presentation).

Suhhonenko I.: Sügavate valimite modelleerimisest (oral presentation).

Board of Directors Meeting, ''Astronomy and Astrophysics" (Tartu, Estonia, 08.05.2004) - L. Leedjärv, K. Annuk, I. Kolka, Riho Koppel.

Conference ''Exploring the Cosmic Frontier: Astrophysical Instruments for the 21st Century" (Berlin, Germany, 18.05.-21.05.2004) - L. Leedjärv.

Summer School ''Cosmology and Planck" (Tuorla Observatory, Finland, 31.05.-04.06.2004) - E. Saar, I. Pärn, L.J. Liivamägi.

Saar E.: Secondary Anisotropies: Clusters of Galaxies, SZ Effect (oral presentation).

All-Russian Astronomical Conference VAK-2004 (Moscow, Russia, 01.06.-09.06.2004) - V.-V. Pustynski.

Pustynski V.-V.: Light Curve Analysis of Eclipsing Precataclysmic Binary Systems UU Sge, V477 Lyr, NN Sco and Evaluation of their Evolutionary State (oral presentation).

NATO Advanced Study Institute ''The Electromagnetic Spectrum of Neutron Stars" (Marmaris, Turkey, 07.06.-18.06.2004) - I. Vurm.

GAIA Photometry Working Group Workshop (Copenhagen, Denmark, 28.06.-29.06.2004) - V. Malyuto.

Malyuto V.: Application of Minimum Distance Classification Method to Simulated Data for GAIA-2 Configuration Using Some Grids of Templates of Different Densities (oral presentation).

Conference ''Plumian 300 - The Quest for a Concordance Cosmology and Beyond" (Cambridge, UK, 05.07.-09.07.2004) - J. Einasto.

14th European Workshop on White Dwarfs (Kiel, Germany, 17.07.-23.07.2004) - V.-V. Pustynski.

Pustynski V.-V.: A New Computer Code for Analysing the Light Curves of Eclipsing Precataclysmic Binaries (PCBs): Application to UU Sge and V477 Lyr (oral presentation).

Conference ''Light-Time Effect in Astrophysics: Causes and Cures of the O-C Diagram" (Brussels, Belgium, 17.07.-23.07.2004) - I. Pustylnik, T. Eenmäe.

Pustylnik I.: Light Time Effect in Selected Semi-Detached and Contact Binaries with Observable Third Components (oral presentation).

Conference ''George Gamow Memorial Conference - Gamow 100" (Odessa, Ukraine, 06.08.-13.08.2004) - I. Pustylnik.

Pustylnik I.: Reflections on George Gamow's Unique Scientific Legacy and Personality (oral presentation).

Conference ''The Environments of Galaxies: from Kiloparsecs to Megaparsecs" (Isle of Crete, Greece, 09.08.-13.08.2004) - J. Vennik.

Vennik J., Hopp U.: A Multiwavelength Study of the Galaxy Content and Environmental Effects in the Dense Group of Galaxies Around IC 65 (poster).

Data Analysis in Cosmology (València University, Spain, 06.09.-10.09.2004) - E. Saar, I. Pärn, L.J. Liivamägi.

Saar E.: Multiscale Methods (oral presentation).

Saar E. was a scientific secretary of this conference.

Stellar Astrophysics with the World Largest Telescopes (Torun, Poland, 07.09.-10.09.2004) - K. Annuk.

Joint European and National Astronomy Meeting JENAM 2004 ''The Many Scales of the Universe" (Granada, Spain, 13.09.-17.09.2004) - M. Gramann, L. Leedjärv, E. Saar.

Saar E.: Multiresolution Morphology of Cosmological Fields (oral presentation).

Leedjärv L.: The Peculiar Symbiotic Star CH Cygni: 40 Years of (Known) Activity (poster).

Symposium ''On the Era and Work of Franz Xaver von Zachs" (Budapest, Hungary, 15.09.-17.09.2004) - I. Pustylnik.

Conference ''Astronomy in Prague and Around" (Prague, Czech Republic, 21.09.2004) - I. Pustylnik.

Pustylnik I.: Petzval Astrograph of Tartu Observatory (oral presentation).

The Three Dimensional Universe with GAIA (Paris-Meudon, France, 04.10.-07.10.2004) - I. Kolka, M. Kama, V. Malyuto.

Kolka I., Eenmäe T., Hirv A., Tuvikene T., Kama M.: Emission Line Stars in the Framework of GAIA (oral presentation).

Malyuto V.: Minimum Distance Method of Classification in Application to GAIA Simulated Photometric Data (poster).

Baryons in Dark Matter Haloes (Novigrad, Croatia, 05.10.-09.10.2004) - A. Tamm.

GAIA Classification-Variability-Alerts Joint Working Group Meeting (Paris, France, 08.10.2004) - V. Malyuto.

GAIA Solar System Working Group Workshop (Lohrmann Observatory, Dresden University of Technology, Germany, 25.11.-26.11.2004) - V. Malyuto.

Astronomical Seminar (Sternberg Astronomical Institute, Moscow, Russia, 10.12.2004) - A. Sapar, A. Aret.

Sapar A., Poolamäe R.: A Compact and Handy Code SMART for Physics and Spectra of Hot Stellar Atmospheres: Results and Problems (oral presentation).

Aret A.: Role of Light-Induced Drift in Formation of Chemical and Isotopic Anomalies in the Atmospheres of Chemically Peculiar Stars (oral presentation).

Workshop ''25 Years After the Discovery: Some Current Topics on Lensed QSO-s" (Santander, Spain, 15.12.-17.12.2004) - J. Pelt.

Pelt J.: Estimation of Time Delays from Unresolved Photometry (oral presentation).


Geophysics

Seminar ''Observational Data in Support of Northern Eurasia Earth Science Partnership Initiative (NEESPI)" (St. Petersburg, Russia, 23.02.-26.02.2004) - T. Nilson.

Nilson T., Peterson U.: Regional Land Cover and Land Cover Change in the Eastern Baltic area (poster).

Joint Finnish-Estonian Remote Sensing Seminar (Tõravere, Estonia, 02.03.2004) - T. Nilson, A. Kuusk, M. Lang, M. Mõttus, U. Peterson.

Lang M.: Forest Reflectance Modelling: a Test on the Network of Permanent Forest Growth Sample Plots (oral presentation).

Kadarik H., Lükk T., Nilson T.: Spectral-Seasonal Signatures of Vegetation in Emajõe Suursoo (oral presentation).

Peterson U.: Issues on Forest Area Change in Eastern Baltic Region (oral presentation).

Paas M., Kuusk A.: Metrological Problems of the CCD Radiometer (oral presentation).

Mõttus M.: Modelling Radiative Transfer in Willow Coppice (oral presentation).

The First COST 726 Member Countries Meeting (Brussels, Belgium, 29.03.2004) - K. Eerme.

Tartu Ülikooli botaanika ja ökoloogia instituudi seminar (Tartu, Estonia, 01.04.2004) - U. Peterson.

Peterson U.: Eesti metsa pindala muutused satelliidipiltidelt mõõdetuna (oral presentation).

Physical Models in Remote Sensing. Course for graduate students, Finnish Forest Research Institute, Vantaa Research Center (Tikkurila, Finland, 13.04.-16.04.2004) - T. Nilson, A. Kuusk, M. Lang.

Nilson T.: Basic Concepts (oral presentation).

Nilson T.: Radiative Transfer in the Atmosphere (oral presentation).

Kuusk A.: Atmospheric Radiative Transfer Packages (oral presentation).

Nilson T.: Aerosol Retrieval Algorithms (oral presentation).

Kuusk A.: Radiative Transfer in Vegetation (oral presentation).

Kuusk A.: Leaf Optical Models (oral presentation).

Nilson T.: Soil Reflectance Models (oral presentation).

Nilson T.: Spectral Signatures (oral presentation).

Kuusk A.: Reflectance Spectra (oral presentation).

Kuusk A.: Radiative Transfer and Canopy Reflectance Models (oral presentation).

Kuusk A.: Application Example - Vegetation Indices (oral presentation).

Kuusk A.: Radiative Transfer Models for Forests (oral presentation).

Nilson T.: Simulation Examples (oral presentation).

Nilson T.: Instruments (oral presentation).

Nilson T.: Research Methodologies (oral presentation).

Kuusk A.: Field Measurements (oral presentation).

Nordic Ozone Group (NOG) Meeting (Helsinki, Finland, 14.04.-15.04.2004) - K. Eerme.

Eerme K., Veismann U., , Maasik E.-M.: On the Sky Background Influence on the UV-B Irradiance (oral presentation).

ETH Workshop (Zürich, Switzerland, 13.04.2004) - A. Kallis.

Kallis A.: Radiation Measurements at Tartu-Tõravere Station (oral presentation).

Tartu Ülikooli geograafia instituudi seminar (Tartu, Estonia, 21.04.2004) - U. Peterson.

Peterson U.: Eesti metsa pindala muutused satelliidipiltidelt mõõdetuna (oral presentation).

I AERONET/PROTONS Symposium (El Arenosillo, Spain, 10.05.-14.05.2004) - O. Kärner.

Kärner O., Eerme K., Kikas Ü., Nilson T., Reinart Aivo, Reinart Anu, Russak V., Sulev M., Veismann U.: Summary of Using the AERONET Tõravere Station Data (poster).

Juubelikonverents ''85 aastat Eesti Rahvuslikku Ilmateenistust" (Tallinn, Estonia, 18.05.2004) - A. Kallis.

Kallis A., Pärn E.: Meteoroloogilise vaatlusvõrgu ajaloost Eestis (oral presentation).

Conference on Research for Rural Development 2004 (Jelgava, Latvia, 19.05.-22.05.2004) - M. Lang, U. Peterson.

Lang M., Lükk T.: Estimation of the Forest Parameters From Satellite Images Using Forest Reflectance Model (oral presentation).

Peterson U.: Mapping Forest Clearcuts in Estonia and in Latvia Using Satellite Landsat Imagery (oral presentation).

Bioklimatoloogia seminar (Kuressaare, Estonia, 25.05.-26.05.2004) - A. Kallis, U. Veismann.

Kallis A.: Ilmanähtuste mõju inimese tervisele (oral presentation).

XXXV COSPAR Plenary Meeting (Paris, France, 18.07.-25.07.2004) - O. Kärner.

Kärner O., Karlsson K.-G.: Sea-Ice Extent Analysis by Means of CM-SAF Cloud Algorithm (poster).

The 8th BSRN Workshop and Scientific Review Meeting (Met Office, Exeter, UK, 26.07.-30.07.2004) - A. Kallis.

Kallis A.: 100 Years of Solar Radiation Measurements in Estonia (oral presentation).

ENVISAT Symposium (Salzburg, Austria, 05.09.-10.09.2004) - A. Reinart.

Reinart A., Pierson D.: Water Quality Monitoring of Large European Lakes Using MERIS Full Resolution Data (poster).

European Aerosol Conference 2004 (Budapest, Hungary, 06.09.-10.09.2004) - O. Okulov.

Teral H., Ohvril H., Okulov O., Russak V., Reinart A., Laulainen N.: Spectral Aerosol Optical Thickness from Solar Broadband Direct Irradiance - Summer 2002 (poster).

VII Keskkonnakaitse alane nõupidamine: Atmosfäär. Inimene. Ultraviolettkiirgus (Türi, Estonia, 09.09.2004) - K. Eerme, U. Veismann, O. Kärner, V. Russak, I. Ansko, S. Lätt.

Eerme K.: UV kiirguse uuringute suunad Euroopas ja Eestis (oral presentation).

Veismann U., Eerme K., Lätt S., Ansko I.: Päikese UV kiirguse spektromeetria (oral presentation).

Eerme K., Veismann U., Maasik E.-M., : UV-B piirkonna 306 nm kitsasriba ja erüteemse kiirguse sõltuvus osoonist ja aerosoolist (oral presentation).

Russak V., Teral H., Ohvril H.: Atmosfääri aerosoolisisaldus Tõraveres (oral presentation).

Maasik E.-M., Eerme K., Kallis A.: Satelliidilt Earth Probe TOMS ja Tõraveres MICROTOPS II abil mõõdetud osooni koguhulkade võrdlus (oral presentation).

Carl Kalki 200. sünniaastapäevale pühendatud ajaloolise klimatoloogia sümpoosion (Tartu, Estonia, 10.09.2004) - A. Kallis, V. Russak.

Kallis A., Russak V.: 100 aastat aktinomeetriliste mõõtmiste algusest Tartus (oral presentation).

Fourth Annual Meeting of the European Meteorological Society. Part and Partner: 5th European Conference on Applied Climatology (ECAC) (Nice, France, 26.09.-30.09.2004) - V. Russak.

Russak V., Teral H., Ohvril H.: Trends in Atmospheric Aerosol Loading in Estonia During the Period 1951-2003 (poster).

Göttingen GIS & Remote Sensing Days (Göttingen, Germany, 07.10.-08.10.2004) - M. Mõttus.

The Third COST 726 Member Countries Meeting (Warsaw, Poland, 21.10.-22.10.2004) - K. Eerme.

Ocean Optics XVII Conference (Fremantle, Australia, 24.10.-29.10.2004) - A. Reinart.

Reinart A., Pierson D., Strömbeck N., Land P., Reinhold M.: A Satellite Based Water Quality Monitoring System for Lakes Vänern and Vättern, Sweden (poster).

Taastuvate energiaallikate uurimine ja kasutamine VI (Tartu, Estonia, 11.11.2004) - M. Sulev, A. Kallis.

Kallis A.: Päikesekiirguse mõõtmistest Eestis (oral presentation).

Problems of Forest Risk Assessment in Russian Federation, (St. Petersburg, Russia, 24.11.-25.11.2004) - U. Peterson.

Peterson U.: Forest Clearcutting in the Russian North-West and its Neighbouring Areas Detected With a Time Series of Landsat Images (oral presentation).

EU Project VULCAN Final Meeting (Budapest, Hungary, 30.11.-03.12.2004) - T. Nilson.

Nilson T.: Reflectance Simulation for Sparse Shrubland. Site in Garraf, Spain, as an Example (oral presentation).

TÜ Geograafia instituudi 85. aastapäeva konverents (Tartu, Estonia, 03.12.-04.12.2004) - U. Peterson.

Peterson U.: Kas Eestis raiutakse rohkem metsa kui naabrite juures Lätis ja Venemaal? (oral presentation).

Workshop of Radiation Climate (St. Petersburg, Russia, 07.12.2004) - V. Russak, A. Kallis.

Russak V.: Changes in Radiation Regime in Estonia (oral presentation).


Miscellaneous

Euroscience Workshop on Science and Society "Scientists, Investigation and Mitigations of Tensions in Society" (St. Petersburg, Russia, 16.03.-19.03.2004) - I. Pustylnik.

Pustylnik I.: About Communication Skills and Tools of Interdisciplinary Contacts on International Scale (oral presentation).

Bernhard Schmidti 125. sünniaastapäevale pühendatud seminar (Tallinn, Estonia, 13.04.2004) - most of the astronomers.

Jõeveer M.: Saavutustest Schmidti teleskoopidega (oral presentation).

Viik T.: Kuulus naissaarlane Bernhard Voldemar Schmidt (oral presentation).

Veismann U.: Schmidti kaamerate optikast (oral presentation).

Professor E.-M. Tiidu juubelikonverents (Tartu, Estonia, 22.04.2004)- J. Pelt.

Pelt J.: Subjektiivsest tõenäosusest (oral presentation).

EUROCEAN 2004 (Galway, Ireland, 10.05.-13.05.2004) - A. Reinart.

Reinart A. (session rapporteur): The Contribution of the Young Generations for the Future of the European Marine Research Area - Marie-Curie Fellowships in the Domain of Marine Sciences (oral presentation).

Eestist COST aktsioonides osalejate seminar-koolitus (Pühajärve, Estonia, 26.08.-27.08.2004) - K. Eerme.

Editing of the Proceedings of the Conference ''Zdenek Kopal's Binary Star Legacy", Kluwer Publishers, Litomysl, 2004 - I. Pustylnik.

Euroscience Open Forum 2004 (Stockholm, Sweden, 25.08.-29.08.2004) - I. Pustylnik.

Pustylnik I.: Estonian Local Section Euroscience Eesti: Outlook (poster).

Euroopa Teaduste Akadeemiate aastakoosolek (Helsinki, Finland, 01.09.-06.09.2004) - J. Einasto.

Struve Meridian Arc - Past, Present, Future (Chisinau, Moldova, 27.09.-29.09.2004) - T. Viik.

Viik T.: How F.G.W. Struve Started His Ambitious Project (oral presentation).

Interdistsiplinaarne konverents ''Inimteadvus ja käitumine muutuvas maailmas" (Tallinn, Estonia, 14.10.-15.10.2004) - K. Eerme, L. Leedjärv, I. Pustylnik, V.-V. Pustynski.

Eerme K.: Põhilised kliima muutusi mõjutavad faktorid Põhja-Euroopas ja Eestis (oral presentation).

Leedjärv L.: Universum inimeses ja inimene Universumis (oral presentation).

Pustylnik I.: Paleoastronomical and Geophysical Data on Global Climate Variations and their Impact on Human Awareness (poster).

L. Leedjärv was a moderator to the session ''Environment, behavior and health".

Information Seminar ''Space for the Benefits of an Enlarged EU" (Brussels, Belgium, 21.10.2004) - L. Leedjärv.

Leedjärv L.: Space activities in Estonia (oral presentation).

European High Level Space Policy Group Meeting (Paris, France, 22.10.2004) - L. Leedjärv.

Interreg Project Partners Meeting (Riga, Latvia, 06.12.-07.12.2004) - L. Leedjärv.


Visits to other Institutes

Astronomy

I. Suhhonenko - Tuorla Observatory, University of Turku (Finland); 01.01.-31.08.2004.
J. Pelt - Oulu University, Oulu (Finland); 22.03.-03.04.2004.
E. Saar - València University, València (Spain); 03.05.-28.05.2004.
T. Nugis - Centre for Astronomy, Nicolaus Copernicus University, Torun (Poland); 25.05.-14.06.2004.
E. Saar - Tuorla Observatory, University of Turku (Finland); 30.05.-07.06.2004.
L. Leedjärv - Tuorla Observatory, University of Turku (Finland); 11.06.-14.06.2004.
K. Annuk - Centre for Astronomy, Nicolaus Copernicus University, Torun (Poland); 05.09.-15.09.2004.
E. Saar - València University, València (Spain); 05.09.-29.10.2004.
I. Pustylnik - Konkoly Observatory (Hungary); 08.09.-18.09.2004.
V. Malyuto - Lohrmann Observatory, Dresden University of Technology, Dresden (Germany); 24.11.-14.12.2004.
A. Sapar, A. Aret, I. Pustylnik - Sternberg Astronomical Institute, Moscow (Russia); 07.12.-12.12.2004.


Geophysics

A. Kallis - Institute for Atmospheric and Climate Science, ETH Zürich (Switzerland); 25.03.-13.04.2004.
A. Kallis - Swiss Federal Research Station for Agroecology and Agriculture, FAL Reckenholz (Switzerland); 09.04.2004.
A. Reinart - Plymouth Marine Laboratory, Plymouth (UK); 12.05.-04.06.2004.
T. Nilson - Facultat de Ciencies, Universitat Autonoma de Barcelona, Barcelona (Spain); 08.06.-18.06.2004.
A. Kallis - Met Office, Exeter (UK); 26.07.-30.07.2004.
A. Reinart - CSIRO Land and Water Division, Canberra (Australia); 02.11.-06.11.2004.
O. Kärner - Finnish Meteorological Institute, Helsinki (Finland); 24.11.-25.11.2004.
V. Russak, A. Kallis - World Radiation Data Centre and A.I. Vojeikov Main Geophysical Observatory, St. Petersburg (Russia); 06.12.-08.12.2004.
A. Reinart - Uppsala University (Sweden) - regularly through the whole year.


Guests of the observatory

Aleksandr Rosenbush - Main Astronomical Observatory, Kiev (Ukraine); 07.01.2004.
Chris Sterken - Vrije Universiteit Brussel (Belgium); 10.01.-14.01.2004.
Pauline Stenberg - Department of Forest Ecology, University of Helsinki (Finland); 02.03.2004.
Jouni Peltoniemi - Finnish Geodetic Institute (Finland); 02.03.2004.
Jaan Praks - Helsinki University of Technology, Laboratory of Space Technology, Espoo (Finland); 02.03.2004.
Terhikki Manninen - Finnish Meteorological Institute (Finland); 02.03.2004.
Miina Rautiainen - Department of Forest Ecology, University of Helsinki (Finland); 02.03.2004.
Pekka Heinämäki - Tuorla Observatory, University of Turku (Finland); 19.04.-23.04.2004, 16.08.-20.08.2004, 28.09.-02.10.2004.
Ilkka Tuominen - Oulu University (Finland); 09.05.-15.05.2004.
Valdar Oinas - NASA Goddard Institute for Space Studies (USA); 09.06.2004.
Petr Škoda - Astronomical Institute of the Czech Academy of Sciences, Ondrejov (Czech Republic); 16.08.-27.08.2004.
Pierluigi Calanca - Swiss Federal Research Station for Agroecology and Agriculture, FAL Reckenholz (Switzerland); 06.09.-11.09.2004.
Pauline Stenberg - Department of Forest Ecology, University of Helsinki (Finland); 14.10.2004.
Ladislav Hric - Astronomical Institute of the Slovak Academy of Sciences, Tatranská Lomnica (Slovakia); 19.10.-02.11.2004.


Seminars at the Observatory

Astronomy

07.01.2004 - Aleksander Rosenbush (Kiev): R CrB Type Stars.
12.01.2004 - Chris Sterken (Brussels): The Story of 1001 Nights.
21.01.2004 - Margus Saal (TÜ): Holograafilise braanigravitatsiooni kosmoloogiline mudel.
04.02.2004 - Enn Saar: OAUV $\&$ TROBAR.
11.02.2004 - Maret Einasto: GD2G.
18.02.2004 - Jaan Pelt: Ainult mõtete lugemisest ei piisa.
10.03.2004 - Valeri Maljuto: Stellar photometric classification methods for GAIA.
17.03.2004 - Jaan Einasto: Superparved ja parved Sloan DR1 ülevaates.
25.03.2004 - Virtuaalplanetaariumi programmi "Starry Night"  võimalused.
31.03.2004 - Mihkel Jõeveer: 120 000 aasta vanune taevakaart ??
14.04.2004 - Izold Pustõlnik: Kokkuvõtted rahvusvahelisest konverentsist "Zdenek Kopali teaduslik pärand kaksiktähtede uurimisvaldkonnas"  (Litomysl, Tšehhi Vabariik).
28.04.2004 - Jaan Einasto: Konverentsist Kaplinnas.
05.05.2004 - Jaan Pelt: Subjektiivsest tõenäosusest.
12.05.2004 - Ilkka Tuominen (Oulu): Problems of Observational Astronomy in Finland.
26.05.2004 - Jaan Einasto: Rio päikese all.
02.06.2004 - Laurits Leedjärv: Astronoomiliste vaatluste tuleviku konverentsist Berliinis.
09.06.2004 - Valdar Oinas (NASA): Tööst NASA's.
26.08.2004 - Petr Škoda (Ondrejov): High Resolution Spectroscopy at Ondrejov 2-m Telescope.
15.09.2004 - Indrek Vurm: NATO suvekool Marmarises teemal ''Kõrge energiaga astrofüüsika".
22.09.2004 - Kalju Annuk: Rahvusvahelisest konverentsist ''Tähefüüsika maailma suurimate teleskoopidega" Torunis.
06.10.2004 - Izold Pustõlnik: Külas Konkoly observatooriumi astronoomidel, kokkuvõtted rahvusvahelisest konverentsist ''Astronomy in and around Prague".
13.10.2004 - Laurits Leedjärv: Kuidas eestlased saaksid osaleda EL kosmoseprogrammides.
27.10.2004 - Ladislav Hric (Tatranská Lomnica): Astronomy in High Tatras.
10.11.2004 - Antti Tamm: Hetkeseisust tumeda aine jaotuse uurimisel barüon-aine abil ehk muljeid Horvaatias, Novigradis toimunud konverentsist.
17.11.2004 - Vladislav Pustynski: Albeedo probleemidest kataklüsmieelsel evolutsioonietapil erinevates kaksiksüsteemides.
24.11.2004 - Tõnu Viik: Struve meridiaanikaar - minevik, olevik, tulevik.
01.12.2004 - Indrek Kolka, Mihkel Kama: GAIA konverents Pariisis.
08.12.2004 - Jaan Einasto: Indiat avastamas.
15.12.2004 - Tõnu Viik: AIP uudised.


Geophysics

23.01.2004 - Markko Paas: CCD-radiomeetri objektiivisisese peegelduse ja hajumise korrektsioon.
19.03.2004 - Madis Sulev: ''Visible-NIR"  spektromeeter.
11.06.2004 - Matti Mõttus: Modelleeritud kiirgusvoogude ja otsekiirguse läbituleku võrdlus mõõtmistega pajuvõsas.
05.11.2004 - Madis Sulev, Matti Mõttus: 1. Taimeelementide optiliste omaduste laboratoorsed mõõtmised (esimesed katsetused FieldSpec-iga). 2. Mõttevahetus lepaistanduse tulevikust.
26.11.2004 - Andres Kuusk, Markko Paas: Poolsfääripiltide radiomeetriline korrektsioon.



Membership in scientific organizations

Academia Europaea - J. Einasto
Akademische Gesellschaft für Deutschbaltische Kultur - T. Viik
American Astronomical Society - J. Einasto
American Optical Society - T. Viik
Board of Directors ''Astronomy and Astrophysics'' - L. Leedjärv
Board of the Tartu Astronomy Club - E. Tago
British Interplanetary Society - U. Veismann
Editorial Board ''Agricultural and Forest Meteorology'' - A. Kuusk
Editorial Board ''Astronomical and Astrophysical Transactions'' - I. Pustylnik
Editorial Board ''Baltic Astronomy'' - T. Kipper
Editorial Board ''Central European Journal of Physics'' - I. Pustylnik
Editorial Board ''Journal of Quantitative Spectroscopy and Radiative Transfer'' - T. Viik
Eesti Astronoomia Selts - K. Annuk, J. Einasto, M. Jõeveer, T. Kipper, I. Kolka, L. Leedjärv, T. Nugis, J. Pelt, A. Puss, I. Pustylnik, M. Ruusalepp, L. Sapar, E. Tago, P. Traat, U. Veismann, T. Viik
Eesti Füüsika Selts - A. Aret, K. Eerme, J. Einasto, T. Kipper, L. Leedjärv, E. Saar, A. Sapar, M. Sulev, P. Tenjes, T. Viik
Eesti Geograafia Selts - A. Kallis
Eesti Kvaliteediühing - U. Veismann
Eesti Looduskaitse Selts - M. Sulev
Eesti Looduseuurijate Selts - K. Eerme, A. Kallis, V. Russak, A. Sapar, M. Sulev, U. Veismann, T. Viik
Eesti Teadlaste Liit - J. Einasto, A. Kallis, T. Viik
Estonian Academy of Sciences - J. Einasto, A. Sapar
Estonian Council of Scientific Competence - T. Viik (Vice-Chair)
Estonian National Committee on Astronomy - J. Einasto, L. Leedjärv (Chair), E. Saar, T. Viik
Estonian Geophysical Committee - K. Eerme
European Astronomical Society - K. Annuk, J. Einasto, M. Gramann, V. Harvig, M. Jõeveer, T. Kipper, I. Kolka, L. Leedjärv, V. Malyuto, T. Nugis, I. Pustylnik, V.-V. Pustynski, E. Saar, A. Sapar, L. Sapar, E. Tago, P. Tenjes, U. Veismann, J. Vennik, T. Viik
European High Level Space Policy Group - L. Leedjärv
EUROSCIENCE - I. Pustylnik
Euro-Asian Astronomical Society - A. Aret, J. Einasto, M. Jõeveer, V. Malyuto, I. Pustylnik, A. Sapar
GAIA Classification Working Group - V. Malyuto
GAIA Photometry Working Group - I. Kolka
German Astronomical Society - J. Einasto
Field Editor ''Agronomie. Agriculture and Environment'' - A. Kuusk
Finance Sub-Committee of the IAU - T. Viik
International Astronomical Union - K. Annuk, J. Einasto, M. Einasto, M. Gramann, U. Haud, M. Jõeveer, T. Kipper, I. Kolka, L. Leedjärv, V. Malyuto, T. Nugis, J. Pelt, I. Pustylnik, E. Saar, A. Sapar, L. Sapar, E. Tago, P. Tenjes, P. Traat, U. Veismann, J. Vennik, T. Viik
Royal Astronomical Society - J. Einasto (associated member)
Society for European Astronomy in Culture - I. Pustylnik
Ultraviolettkiirguse, osooni ja aerosoolide uurimise koordineerimise Eesti Nõukogu - K. Eerme, A. Kallis, U. Veismann.



Teaching

Lecture courses

Astronomy

Astronomical Technics - U. Veismann, Tartu University.

Physics and Evolution of Close Binary Systems and Intrinsic Variables - I. Pustylnik, Tartu University.

Swift Stellar Evolutionary Code, Seminars - I. Pustylnik, Tartu University.

Statistical Data Processing in Astronomy - J. Pelt, Tartu University.

Physical Cosmology - M. Gramann and E. Tago, Tartu University.

Stellar Wind and Formation of Spectral Lines in Stellar Envelopes - T. Nugis, Tartu University.

Astronomy - P. Tenjes, Tartu University.

Master Seminar in Astrophysics - P. Tenjes, Tartu University.

Atomic and Subatomic Physics I - P. Tenjes, Tartu University.

Atomic and Subatomic Physics - P. Tenjes, Tartu University.

Mathematical Physics I - P. Tenjes, Tartu University.

Methods of Mathematical Physics - P. Tenjes, Tartu University.

Introduction to Thermodynamics and Statistical Physics - P. Tenjes, Tartu University.

Astronomy course for the Nõo High School, held at the Observatory - K. Annuk, J. Einasto, L. Leedjärv, A. Puss, M. Ruusalepp, T. Viik.


Geophysics

Environmental Sciences - K. Eerme, Tartu University.

Introduction to Geophysics - K. Eerme, Tartu University.

Computer-Aided Measurements - U. Veismann together with A. Mirme, Tartu University.

Image Processing in Remote Sensing - U. Veismann together with A. Luts, Tartu University.

Remote Sensing in Forestry - T. Nilson and M. Lang, Estonian Agricultural University.

Remote Sensing of Nature - T. Nilson and M. Lang, Estonian Agricultural University.

Vegetation Remote Sensing - T. Nilson, Tartu University.

Fundamentals of Remote Sensing - U. Peterson, Tartu University.

Geographic Information Systems - U. Peterson and M. Lang, Estonian Agricultural University.


Popular lectures

18 intervjuud BNSile, raadiole ja televisioonile - T. Viik.

29. veebruar ja liigaastad (Vikerraadio, Maalehega maale, 29.02.2004) - L. Leedjärv.

Universumi paisumiskiirusest ja tumedast energiast (TÜ astrofüüsika magistriseminar, Tartu University, 04.03.2004) - I. Vurm.

Kas 10. planeet Päikesesüsteemis? (Vikerraadio, Vikerhommik, 16.03.2004) - L. Leedjärv.

Ainult mõtete lugemisest ei piisa (Visualiseerimisest statistikas) (Tartu University, 09.04.2004) - J. Pelt.

Veenuse üleminek Päikesest (Vikerraadio, Saaremaa Kadi Raadio, Eesti Televisioon (AK), 08.06.2004) - L. Leedjärv.

Tartu Ülikooli korraldatud Eesti füüsikaõpetajate koolitus (Tõravere, Estonia, 29.06.2004) - J. Einasto, K. Eerme, L. Leedjärv, T. Viik.

Eerme K.: Kui selge või kui segane on praegu kliima muutumise perspektiiv?

Einasto J.: Ettekanne kosmoloogiast.

Leedjärv L.: Tähtede rollist Universumis.

Viik T.: Taevakehad Päikesesüsteemi kaugetel äärealadel.

Matemaatilised ennustused (Astronoomiahuviliste IX Üle-Eestiline kokkutulek, Krabi, 12.08.2004) - J. Pelt.

Süvataeva objektide vaatlemisest (Astronoomiahuviliste IX Üle-Eestiline kokkutulek, Krabi, 12.08.2004) - T. Eenmäe.

Taevakehade kaalumise meetoditest (Astronoomiahuviliste IX Üle-Eestiline kokkutulek, Krabi, 14.08.2004) - M. Jõeveer.

Nähtav ja nähtamatu aine (Astronoomiahuviliste IX Üle-Eestiline kokkutulek, Krabi, 15.08.2004) - J. Einasto.

Georgi Gamov 100 (Astronoomiahuviliste IX Üle-Eestiline kokkutulek, Krabi, 15.08.2004) - I. Pustylnik.

Sedna - uut tüüpi taevakeha (Astronoomiahuviliste IX Üle-Eestiline kokkutulek, Krabi, 15.08.2004) - T. Viik.

Veenuse üleminek Päikesest (Astronoomiahuviliste IX Üle-Eestiline kokkutulek, Krabi, 15.08.2004) - M. Kama.

Uued taevakehad Päikesesüsteemi ääremaadel (TÜ astrofüüsika magistriseminar, Tartu, 02.09.2004) - T. Viik.

Matemaatilised ennustused (Tartu University, 09.09.2004) - J. Pelt.

40 aastat observatooriumi Tõraveres (Eesti Televisioon (Terevisoon), Kuku Raadio, Raadio Elmar, 01.10.2004) - L. Leedjärv.

Tõravere Eesti kultuuriloos (Tartu Observatooriumi uue kompleksi avamise 40. aastapäev, Tõravere, 01.10.2004) - T. Viik.

Struve meridiaanikaar - minevik, olevik, tulevik (Tartu, Tähetorni Astronoomiaring, 02.11.2004) - T. Viik.

Tume aine ja energia Universumis (Tartu, Tartu Tähetorni Astronoomiaring, 16.11.2004) - E. Tago.

Supervising of graduation theses

M. Lang - M. Jürjo: Tartumaa segaprügilate seire satelliidipiltidelt / Detecting Landfills in Tartu County Using Satellite Images, Estonian Agricultural University.

M. Lang, T. Nilson - M. Saar: Puude arvu ja rinnasdiameetri määramine aerofotodelt / Assessment of the Tree Diameter at Breast Height and Number of the Trees From Aerial Photographs, Tartu University.

T. Nilson, M. Lang - P. Jentson: Erinevate metsatüüpide heleduste korrelatsioonimaatriksid satelliidipiltidelt / Correlation Matrices of Different Forest Types Estimated from Satellite Images, Estonian Agricultural University.

J. Pelt - N. Olspert: Mikroläätse efekti hindamine kaksik-kvasari heleduskõverate põhjal / Estimation of the Microlensing Effect from Double-Quasar Light Curves, Tartu University.


Supervising of M.Sc. and Ph.D. theses

T. Nilson - M. Mõttus: Shortwave Solar Radiation Field Inside Willow Canopy (Ph.D.), Tartu University.

A. Kuusk - M. Paas: Study of Radiative Transfer in Forests Using a CCD-Radiometer. Radiometric Correction of Digital Images (M.Sc.), Tartu University.

A. Reinart - B. Paavel: Optical Properties of Lake Peipsi (M.Sc.), Tartu University.


Refereeing of theses

L. Leedjärv - S. Katajainen: Polarimetric Studies of Magnetic Cataclysmic Variables (Ph.D.), University of Turku (Finland).

E. Tago - N. Olspert: Estimation of the Microlensing Effect from Double-Quasar Light Curves / Mikroläätse efekti hindamine kaksik-kvasari heleduskõverate põhjal (B.Sc.), Tartu University.

M. Mõttus - A. Pugatšova: Atmosfääriaerosooli mõõtmespektri iseloomu ja osakeste kogukontsentratsiooni seose uurimine õhumassi päritoluga (M.Sc.), Tartu University.

E. Saar - M. Saal: Studies of Pre-Big Bang and Braneworld Cosmology (Ph.D.), Tartu University.