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Project titleNew generation of stellar population models for galaxy evolution studies using the Big Data approach

AffiliationFederal State Budgetary Educational Institution of Higher Education Lomonosov Moscow State University,

Research area 02 - PHYSICS AND SPACE SCIENCES, 02-704 - Physics and evolution of stellar and interstellar medium

Keywordsextragalactic astronomy, galaxy evolution, stellar libraries, stellar population models, intermediate mass black holes, data science, big data

Annotation
The study of galaxy evolution is a cornerstone of modern astrophysics and observational cosmology. Numerical models predict the statistical properties of galaxies (the mass function, the star formation history etc.), which agree well with the observations. At the same time, detailed studies of nearby galaxies have found significant discrepancies between observations and theory, some of which are related to oversimplifications introduced by theoretical modeling and a substantial part arises from the misunderstanding of the physics of processes occurring in galaxies. Significant progress in the understanding of the phenomena occurring in galaxies can be achieved by direct comparison of properties of objects at different distances - from nearby galaxies that are available for very detailed studies to distant, where it is possible to obtain only their general properties, but which in this case are at the earlier stages of evolution . It is very important to use the very same methods of data analysis, in order to avoid systematic errors of different nature, which can be mistakenly considered as being physical phenomena. Although for the past years astrophysics has accumulated a huge material, which includes the results of the large spectral and photometric surveys with data for millions of both near and distant stellar systems, there still has been no attempt to carry out joint analysis of a large sample of galaxies of different types, using the same set of methods when working with data. The key methodological component of our project is the development of new generation stellar population models with the quality that is superior to all the alternatives existing in the literature. To achieve that, it is necessary first to compile stellar libraries in the optical and near-infrared spectral ranges. This is extremely large effort which is on the other hand is highly demanded in the world astronomical community: stellar library and stellar population model papers are cited 400-1500 times in the first 5-10 years from their release. We have started this program in 2012. Since then, as a result of peer-reviewed calls for proposals, we have been awarded 25 observing nights at the 6.5-meter Magellan telescope during which we obtained more than 2000 spectra of 1000 stars (given the operation cost of Magellan telescope $40000/night it is equivalent to $1 mln. already awarded to our project). During 2017-2019 we plan to complete this large-scale project which may become the highest impact study in Russian astrophysics for the next 10-15 years. For the first time our methods to deal with large samples of galaxies, including the detailed analysis of their optical spectra, combined with significant experience of the automated work with large public sky surveys at X-ray and radio wavelengths will help to perform a large-scale search for a mysterious population of intermediate mass black holes both in the nuclei and the outskirts of galaxies. The importance of finding at least a few reliable intermediate-mass black holes can not be overstated, as after the decade of active searches my a number of international research groups have brought only one reliable candidate. Discovery of a new candidate or even an entire population will immediately allow us to impose important constraints on the standard theory of hierarchical galaxy formation, to identify the relationship between the presence of intermediate mass black holes and properties of host galaxies including their environment, to better understand the conditions for the growth of supermassive black holes in galactic nuclei and the relative role of accretion of interstellar gas or smaller black holes mergers in this process. In addition, the new generation of our stellar population models will be used to analyze both publicly available observational data obtained with the largest telescopes in Russia and abroad for several dozen individual galaxies of various morphological types from giant LSB galaxies to dwarf elliptical galaxies. We plan to establish the relative importance of different mechanisms of evolution of galaxies, both internal (such as star formation feedback, self-enrichment of the interstellar medium with heavy elements, the initial mass function) and external (merging and interaction of galaxies, tidal effects, the impact of hot intergalactic gas), also to examine the relationship between the mass of central black holes and global galaxies characteristics, all of which will greatly improve the understanding of the physical processes occurring in the Universe.

Expected results
The project will produce in 3 years at least 15 papers in journals indexed in the Web of Science, of which at least 12 will be published in prestigious international refereed astronomical journals such as Monthly Notices of the Royal Astronomical Society (United Kingdom, Impact Factor = 5.107), Astrophysical Journal (USA, IF = 5.993), Astrophysical Journal Supplement (IF=11.7), Publications of the Astronomical Society of the Pacific (USA, IF = 3.469). Given the solid positive experience of the project’s principal investigator and one of the main co-investigators in publishing lead author’s papers in the interdisciplinary journal Science (IF = 33.6) and co-authoring papers in Nature (IF = 41.4), we hope that one or two papers coming from this project will be published in these prestigious journals and / or in the newly-established journal Nature Astronomy. The most important methodological result of the presented project will be a new generation of models of stellar populations in the optical and near-infrared spectrum range, and the publication of a unique library of infrared stellar spectra with medium resolution, which will be highly demanded by the world scientific community for the next 20-30 years with the advent of new generation of telescopes mostly working in the near-infrared domain. Using detailed modeling of complex profiles of emission lines in the spectra of galaxies for the first time we will measure a large number of masses of black holes contained in active galactic nuclei which was previously unavailable to the sample sizes of order of tens of thousands of galaxies and even more. In addition to new constraints on the black hole scaling relations obtained as a result we will select candidates to the central intermediate mass black holes, the existence of which is predicted by standard theories of galaxy formation, but which have not yet been confirmed observationally, despite of all the efforts of the international scientific community. In addition to the scientific articles, we are planning to expand the multi-wavelength RCSED catalog (Reference Catalog of Spectral Energy DIstributions of galaxies), its infrastructure and web service by including analysis of broad line components of AGN galaxies and distant quasars, which will allow other scientific groups to conduct comprehensive studies of AGN phenomena (revisiting of scale relation, search for double-peaked AGN, study of feedback from AGN). Also, we will expand the existing popular web service "K-corrections calculator" (http://kcor.sai.msu.ru/) adding there galaxies at intermediate redshifts that will significantly increase its value to the scientific community due to the large amount of data on distant galaxies obtained over the past 10 years.

Annotation of the results obtained in 2019
During the third year of the project, our research team published 3 articles, one article was accepted for publication in international journals indexed in the Web of Science system (three in Q1, one in Q3), 4 articles were published in proceedings and 4 talk were presented on international conferences and 3 invited talks at a seminar of the Harvard-Smithsonian Center for Astrophysics. For the first time, spatially resolved stellar kinematics were obtained for 9 ultra diffuse dwarf galaxies in the Coma cluster. The mass fraction of dark matter is estimated, the evolutionary relationship of ultra diffuse galaxies and dwarf elliptical galaxies are obtained. These results were published in an article in the Astrophysical Journal, press releases were issued at MSU and RSF, which were widely discussed in the press. A giant low surface brightness galaxy UGC1378 was investigated using data from the 6th telescope of the BTA SAO RAS and the 6.5th telescope of the MMT (Arizona, USA). It was shown that giant low surface brightness galaxies have several mechanisms of formation and evolution, and their combination into a single class of objects is not entirely correct. An article with the results was published in the Monthly Notices of the Royal Astonomical Society and was also featured in the press. Planetary nebulae were discovered in globular clusters from systems of 4 giant elliptical galaxies in the Virgo cluster, the frequency estimates of the planetary nebulae occurrence were obtained, and a conclusion was drawn about the possible influence of the binary system formation in globular clusters on their origin. The work was published in the Astrophysical Journal. One of the methodological results of the third project year, due to its interdisciplinary nature, can be applied in various fields of science, and not just in physics and astronomy. This result from the field of computational mathematics is a new hybrid algorithm for minimizing complex functionals, some of the parameters of which are defined on a discrete grid of values, and another part - on a continuous set of parameter space. This algorithm can be applied to the search for parameters of complex models in many branches of science and technology, when such models are defined on a discrete grid of values, and it is assumed that the change along the grid is quite smooth, but at the same time there are parameters defined on continuous subsets that change the look of the model. Based on this algorithm, we have developed a new technique for analyzing the spectra of stars and determining the parameters of stellar atmospheres. We have completed work on the project’s website dedicated to stellar libraries and stellar population models (https://sl.voxastro.org/). The website provides access to 1,700 stellar spectra from UVES-POP and INDO-US optical stellar libraries, as well as the first release of LCO-SL infrared stellar library data.

Publications

1. Berdnikov, L. N.; Kniazev, A. Yu.; Dambis, A. K.; Kravtsov, V. V.; Pastukhova, E. N.; Katkov, I. Y. CCD Observations and Period Change of the Type ab RR Lyrae Star DV Mon Astrophysical Bulletin, Volume 74, Issue 2, pp.183-195 (year - 2019) https://doi.org/10.1134/S199034131902007X

2. Chilingarian I.V., Afanasiev A.V., Grishin K.A., Fabricant D., Moran S. Internal Dynamics and Stellar Content of Nine Ultra-diffuse Galaxies in the Coma Cluster Prove Their Evolutionary Link with Dwarf Early-type Galaxies Astrophysical Journal, Volume 884, Issue 1 (year - 2019) https://doi.org/10.3847/1538-4357/ab4205

3. Kniazev A.Yu., Malkov O.Yu., Katkov I.Yu., Berdnikov L.N. Long-period eclipsing binaries: towards the true mass-luminosity relation. I. The test sample, observations and data analysis Research in Astronomy and Astrophysics, - (year - 2020)

4. Saburova, Anna S.; Chilingarian, Igor V.; Kasparova, Anastasia V.; Katkov, Ivan Yu; Fabricant, Daniel G.; Uklein, Roman I. UGC 1378 - a Milky Way sized galaxy embedded in a giant low surface brightness disc Monthly Notices of the Royal Astronomical Society, Volume 489, Issue 4, p.4669-4678 (year - 2019) https://doi.org/10.1093/mnras/stz2434

5. Sun, Weijia; Peng, Eric W.; Ko, Youkyung; Côté, Patrick; Ferrarese, Laura; Lee, Myung Gyoon; Liu, Chengze; Longobardi, Alessia; Chilingarian, Igor V.; Spengler, Chelsea; Zabludoff, Ann I.; Zhang, Hong-Xin; Cuillandre, Jean-Charles; Gwyn, Stephen D. J. The Next Generation Virgo Cluster Survey. XVII. A Search for Planetary Nebulae in Virgo Cluster Globular Clusters Astrophysical Journal, Volume 885, Issue 2, article id. 145, 13 pp. (year - 2019) https://doi.org/10.3847/1538-4357/ab49fb

6. Borisov S., Chilingarian I., Rubtsov E., Ledoux C., Melo C., Grishin K. The Recalibration of the UVES-POP Stellar Spectral Library Astronomical Society of the Pacific Conference Series, volume 522, pages 591 (year - 2020)

7. Chilingarian I.V. Quick and Accurate Data Reduction for Intermediate-resolution Echelle Spectrographs at Magellan Astronomical Society of the Pacific Conference Series, Vol. 522, p.623 (year - 2020)

8. Grishin K., Chilingarian I., Katkov I. Open-source Web Tools for Spectroscopic and Imaging Data Visualization for the VOXAstro Initiative Astronomical Society of the Pacific Conference Series, Volume: 523 Pages: 33-36 (year - 2019)

9. Rubtsov, E; Chilingarian, I; Borisov, S; Katkov, I Stellar Atmospheric Parameters from Full Spectrum Fitting of Intermediate- and High-resolution Spectra against PHOENIX/BT-Settl Synthetic Stellar Atmospheres Astronomical Society of the Pacific Conference Series, Volume: 523 Pages: 289-292 (year - 2019)

10. - Ультра-диффузные галактики могут быть родственниками карликам gazeta.ru, - (year - )

11. - Ученые МГУ выяснили родственные связи тусклых галактик с карликовыми РИА Новости, - (year - )

12. - Ультра-диффузные галактики могут быть родственниками карликам https://indicator.ru/, - (year - )

13. - Ультрадиффузные галактики – родственники карликов Поиск, - (year - )

Annotation of the results obtained in 2017
During the first year of the RSCF project's implementation, a young scientific team from the Sternberg Astronomical Institute of the Moscow State University published or got accepted five articles in prestigious international peer-reviewed scientific journals, and two more articles are under discussion with reviewers. One of the main results of our work was the discovery of a population of black holes of intermediate mass in the centers of small galaxies. Observational searches for these hypothetical objects have been lasting for about 30 years, involving many groups of scientists around the world. For the first time we managed to show that these black holes are quite often found in the local Universe. Thus, we have established new stronger constraints on the origin of supermassive black holes in the early universe, observed in the form of bright distant quasars -- apparently, they originated from small black holes, rather than from the direct collapse of huge clouds of gas, as many previously thought. This work required special observations in the optical range on the 6.5-meter Magellan telescope in Chile, as well as observations at the European space observatory XMM-Newton as well as intensive work with the catalog of galaxies RCSED (http://rcsed.sai.msu.ru), created by our group last year. We studied the properties of giant discy galaxies with radii higher than 30 kpc. In particular we showed that bars occur more frequently in giant galaxies. The bars in turn can influence the evolution of central black holes by inducing the inflow of gas to the centre of a galaxy. The activity of central black hole can regulate the processes of gas outflow related to the fading of star formation. The research of the intrinsic dynamical properties of ultra-compact dwarf galaxies resulted in the discovery of supermassive black holes in two such objects, and the upper estimate for the central black hole mass in two other UCDs. The new data brings a strong support for the hypothesis that the tidal stripping of once bigger progenitor is a main formation mechanism for massive ultra-compact dwarf galaxies.

Publications

1. Afanasiev A.V., Chilingarian I.V., Mieske S., Voggel K.T., Picotti A., Hilker M., Seth A., Neumayer N., Frank M., Romanowsky A.J., Hau G., Baumgardt H., Ahn C., Strader J., den Brok M., McDermid R., Spitler L., Brodie J., Walsh J.L. A 3.5 million Solar masses black hole in the centre of the ultracompact dwarf galaxy fornax UCD3 Monthly Notices of the Royal Astronomical Society, - (year - 2018) https://doi.org/10.1093/mnras/sty913

2. Chilingarian I.V., Asa'd R. Star Clusters as Tracers of Star Formation and Chemical Evolution: the Chemical Enrichment History of the Large Magellanic Cloud The Astrophysical Journal, - (year - 2018)

3. Saburova A.S. What made discy galaxies giant? Monthly Notices of the Royal Astronomical Society, Volume 473, Issue 3, p. 3796-3809 (year - 2018) https://doi.org/10.1093/mnras/stx2583

4. Voggel K.T., Seth A.C., Neumayer N., Mieske S., Chilingarian I.V., Ahn C., Baumgardt H., Hilker M., Nguyen D.D., Romanowsky A.J., Walsh J.L., den Brok M., Strader J. Upper Limits on the Presence of Central Massive Black Holes in Two Ultra-compact Dwarf Galaxies in Centaurus A The Astrophysical Journal, Volume 858, Issue 1, article id. 20, 15 pp. (year - 2018) https://doi.org/10.3847/1538-4357/aabae5

5. Zasov A.V., Saburova A.S., Egorov O.V., Afanasiev V.L. Young stellar clumps in the interacting systems: Arp305 Monthly Notices of the Royal Astronomical Society, - (year - 2018) https://doi.org/10.1093/mnras/sty1017

Annotation of the results obtained in 2018
During the second year of the project, our research team published 6 articles in prestigious international journals, indexed in the Web of Science system (all in Q1) and made 19 reports at Russian (2) and international (17) conferences, including 3 invited report. According to the results of the project, students engaged in its implementation, were prepared 2 undergraduate theses and 3 MSc theses. The main scientific result of the project, published during the 2nd year, was the paper on the discovery of a population of intermediate mass black holes, published in the prestigious international journal Astrophysical Journal in July 2018. The work was widely reported in the media and in less than a year after publication it was already quoted 22 times, which put it in the top 6% of all scientific articles published in 2018 in the field of knowledge "astronomy". Work was carried out on the preparation of large samples of stellar spectra for the further construction of stellar population models. The used optical spectra of stars from the UVES-POP libraries (more than 400 spectra of high spectral resolution) and INDO-US (more than 1200 spectra of average spectral resolution) were recalibrated taking into account additional photometric data. For all the stars, using the methods developed by us, the parameters of stellar atmospheres were determined. The results of this part of the project are available on the website http://sl-dev.voxastro.org/, developed by members of our team. We studied giant low surface brightness galaxies UGC1922 and UGC1378. As it follows from the analysis of spectral long-slit and photometrical data these systems have different formation scenarios. UGC1922 was formed as a result of merging of 3 massive galaxies while UGC1378 had more quiescent evolution. Apparently the formation history of UGC1378 included two stages. At the first stage the central high surface brightness part was formed in the similar way as it was proposed for Milky Way that included minor mergings. At the second stage the gas-rich low surface brightness disc might be formed from the gas accreted from a filament. We have done a number of studies on the properties of the vertical structure of edge-on galactic discs: an article on the three galaxies in the Fornax cluster cluster was published; we have prepared an article on the unique giant galaxy NGC7572; we have processed observational materials for all edge-on galaxies of the studied sample.

Publications

1. Chilingarian I.V., Katkov I.Y., Zolotukhin I.Yu., Grishin K.A., Beletsky Y., Boutsia K., Osip D.J. A Population of Bona Fide Intermediate-mass Black Holes Identified as Low-luminosity Active Galactic Nuclei The Astrophysical Journal, Volume 863, Issue 1, article id. 1, 16 pp (year - 2018) https://doi.org/10.3847/1538-4357/aad184

2. Katkov I.Y., Kniazev A.Y., Kasparova A.V., Sil'chenko O.K. The imprint of the thick stellar disc in the mid-plane of three early-type edge-on galaxies in the Fornax cluster Monthly Notices of the Royal Astronomical Society, - (year - 2018) https://doi.org/10.1093/mnras/sty3268

3. Margutti R., Metzger B. D., Chornock R., Vurm I., Roth N., Grefenstette B.W.,Savchenko V.,Cartier R.,Steiner J.F., Terreran G.,Margalit B.,Migliori G., Milisavljevic D.,Alexander K.D., Bietenholz M.,Blanchard P. K.,Bozzo E.,Brethauer D., Chilingarian I.V. An Embedded X-Ray Source Shines through the Aspherical AT2018cow: Revealing the Inner Workings of the Most Luminous Fast-evolving Optical Transients ASTROPHYSICAL JOURNAL, Volume: 872 Issue: 1 Article Number: 18 (year - 2019) https://doi.org/10.3847/1538-4357/aafa01

4. Raymond J.C., Koo B.C., Lee Y.H., Milisavljevic D., Fesen R.A., Chilingarian, I The Temperature and Ionization of Unshocked Ejecta in Cas A ASTROPHYSICAL JOURNAL, Volume: 866 Issue: 2 Article Number: 128 (year - 2018) https://doi.org/10.3847/1538-4357/aadf93

5. Saburova A.S., Chilingarian I.V., Katkov I.Yu., Egorov O.V., Kasparova A.V., Khoperskov S.A., Uklein R.I., Vozyakova O.V. A Malin 1 'cousin' with counter-rotation: internal dynamics and stellar content of the giant low surface brightness galaxy UGC 1922 Monthly Notices of the Royal Astronomical Society, Volume 481, Issue 3, Pages 3534–3547 (year - 2018) https://doi.org/10.1093/mnras/sty2519

6. Zasov A.V., Saburova A.S., Egorov O.V., Dodonov S.N. Spectral observations of the systems with the disturbed spiral arms: Arp 42, Arp 82, and Arp 58 Monthly Notices of the Royal Astronomical Society, Volume 486, Issue 2, p.2604-2617 (year - 2019) https://doi.org/10.1093/mnras/stz1025

7. Chilingarian I., Grishin K., Afanasiev A., Fabricant D., Katkov I. Diffuse post-starburst galaxies: a smoking gun of formation of ultra-diffuse galaxies via ram pressure stripping International Astronomical Union Proceedings Series, - (year - 2019)