SCIENTIFIC AWARDS1. The First Place for Competition in Honor of Yu. Gagarin (Moscow, Russia, 1999);
2. The John Templeton Foundation and the Peter Gruber Foundation Cosmological Prize for Young Researcher Competition at the Science & Ultimate Reality Symposium in Honor of J.A.Wheeler (Princeton, New Jersey, USA, 2002);
3. The Personal Grant of Russian Foundation "INTEGRATSIYA" for special one month course in Astronomical Observatory in Naples, Italy (Moscow, Russia, 2004);
4. The Personal One Year Grants of Moscow State University for young researches (Moscow, Russia, 2005, 2007, 2009);
5. The INTAS for young researchers (2006 — 2007);
6. The prize I. I. Shuvalov II for the establishment of new methods for the study of cosmic strings and dark energy (2013).
SUMMARY OF RESEARCHO.S. is the specialist in the field of cosmology and relativistic astrophysics, author of more than 130 scientific papers, and popular scientific papers; coauthor of 3 monographs (“Space astrometric experiment OZIRIS” Boyarchuk A. A., et al. \\ “Vek-2”, Fryazino, 350 p., 2005 (IN RUSSIAN); “Astronomy: century XXI” ed. by V. G. Surdin \\ “Vek-2”, Fryazino, 622 p., 2022 (IN RUSSIAN); “Multichannel astronomy” Alexeyev S.O. et al. \\ “Vek-2”, Fryazino, 528 p., 2019 (IN RUSSIAN)), the author of monograph “Fundamentals of mathematical processing of observational and experimental data for astronomers” \\ “MSU”, ISBN 978-5-19-011930-5, 286 с. 2024 (IN RUSSIAN). O.S. is the author of two courses for students of astronomical Department of the Physical faculty of M.V. Lomonosov Moscow state University: "The mathematical processing of observations" (2015) and “The mathematical processing of observational and experimental data" (2014).
O.S. (in collaboration with M. V. Sazhin and S. O. Alexeyev) created and developed a model of evaporation relic black holes, putting the observational constraints.
O.S. (in collaboration with M. V. Sazhin) created a new scientific direction for the search of cosmic strings by methods of modern astrophysics:
1) in the optical range (search of chains of the gravitational-lens events with a special structure) for astrophysical instruments with high angular resolution, including the space-based telescopes (it was received observation time on the HST);
2) in the radio range with respect to astrophysical space-based instruments (WMAP and Planck).
Main results for the last 5 yearsInvestigation of wormholes (WH). A study of geodesics in the gravitational field of WH has been carried out, and the possibility of proving the existence of WH by methods of observational astronomy in the current and future experiments by detecting an additional disturbing acceleration component of an astrophysical system containing WH has been investigated. Geodetics have been obtained, and estimates of the necessary observational resources have been carried out.
Cosmic string (CS) research. New possibilities for further observational CS search are proposed and substantiated: for the first time, it is shown that taking into account CS geometry (tilt and bend) cardinally affects one of the main observational methods for CS search (chains of gravitational-lens images of galaxies). These theoretical developments were applied to the analysis of observational data from the binary galaxy SDSSJ110429.61+233150.3, previously found in the field of the assumed CS (CSc-1); (observations with the Himalayan Chandra Telescope, 2.0 m, 2022). For the first time, the fundamental problems of approximate theoretical models are indicated, within the framework of which the evolution of both CS networks and single CS are traditionally considered, and for the first time the rejection of the traditional search for extended chains of gravitational-lens pairs is justified. A new CS search strategy is proposed. A strategy is proposed for the systematic analysis of binary quasars (having a gravitationally lensed nature and an unidentified lens object) as lensed on CS.
Additional information about the activities 1. Chairman of the
A.L. Zelmanov Seminar on Gravitation and Cosmology 2. Member of the
MOIP 3. Chief editor of the Great Russian Encyclopedia.
INTERNATIONAL ACTIVITYO.S. was the scientific supervision in cosmic string searching of students from Naples University Federico II, Physical Department, Naples, Italy (2017).
O.S. participated in more than 40 international scientific conferences (1999 – 2025).
LIST OF MAIN PUBLICATIONS (2020 – 2024)[1] Moiseev I. A., Sazhina O. S. «A strategy for wormhole search using observational astronomy» // MODERN ASTRONOMY: FROM THE EARLY UNIVERSE TO EXOPLANETS AND BLACK HOLES. — Vol. 1 of
PHYSICS OF GALAXIES AND COSMOLOGY. — Special Astrophysical Observatory of the Russian Academy of Sciences Special Astrophysical Observatory of the Russian Academy of Sciences: 2024. — P. 227–233. ABSTRACT: We present a promising strategy for wormhole (WH) search using astronomical observations. By identifying a net effect of anomalous gravitational acceleration may allow for assumptions regarding the hidden WH nature of a black hole (BH). We provide an upper estimate of this effect for several stars in known BH systems such as S2 and S62 orbiting around Sgr A*; along with modeling a synthetic system consisting of a traversable WH, a star on our side and a perturbing object on the other side of a WH. We also consider recently discovered objects from GAIA catalogue data – GAIA BH1, BH2 and BH3. We show that in the traversable WH model a perturbing object (star) located on the other side of the WH throat is capable of causing a significant anomalous acceleration of an object (star) on the observer’s side. This effect is observed to be more significant than other competing factors, including disturbances from nearby stars and the influence of the dark matter halo. The estimated magnitude of the anomalous acceleration varies from 10-4 to 10-2 cmsec, which corresponds to the current accuracy of acceleration measurements. In the future, this may allow for a more precise estimation of the desired effect. [
DOI ]
[2] M. Safonova, I. I. Bulygin, O. S. Sazhina et al. «Deep photometry of suspected gravitational lensing events: Potential detection of a cosmic string» //
Bulletin de la Societe Royale des Sciences de Liege. — 2024. — Vol. 93, no. 2. — P. 819–825. Cosmic strings (CS) are one-dimensional cosmological-size objects predicted in realistic models of the early Universe. Analysis of the cosmic microwave background (CMB) anisotropy data from the Wilkinson Microwave Anisotropy Probe (WMAP) and Planck surveys revealed several CS candidates. One of the candidates, CSc-1, was found to be most reliable because of the statistically significant chains of gravitational lensing (GL) candidates in its field. We observed the brightest of the objects in the CSc-1 field, a galaxy pair SDSSJ110429.61+233150.3. The significant correlation between the spectra of the two components indicates the possible GL nature of the pair. Our simulations of observational data in the CSc-1 field shows that a large number of pairs can be explained by the complex geometry of the CS. Simulations of the SDSSJ110429 galaxy pair has shown that the observed angle between the components of the pair can be explained if the CS is strongly inclined and, possibly, bent in the image plane. In our preliminary data, we also detected the sign of the sharp isophotal edge in one image, which along with CMB and spectral data strongly suggests the possibility of a CS detection. Comments:6 pages, 4 figures, Accepted at the Bulletin de la Société Royale des Sciences de Liège, 2023. [
DOI ]
[3] Bulygin I., Sazhin M., Sazhina O. «Theory of gravitational lensing on a curved cosmic string» //
European Physical Journal C. — 2023. — Vol. 83. — P. 844. It is discussed in detail the complete mathematical model of gravitational lensingon a single cosmic string (CS) of general shape and position with respect tothe line of sight. CS are one-dimensional extended objects assuredly predictedby modern cosmology. The presence of CS changes the global geometry of theUniverse, could clarify the properties of the early Universe, including inflationmodels, and could serve as a unique proof of higher-dimensional theories. Despitethe fact that CS have not yet been reliable detected, there are several strong independentindications of the existence of the CS, based of CMB analysis and searchof gravitational lens chains with special properties (The recent new indication ofthe existence of the CSs is the nHz gravitational waves in the NANOGrav andother PTA Collaborations data.) However, early considered models of straight CSpresented only a small fraction of the general CS-configurations to be observed.Now we propose model which could significantly increase the possibilities ofCS observational search. It is considered more realistic models have necessarilyinclude the inclinations and bends of the CS. Besides, the recent analysis ofobservational data on the search for gravitational-lens candidates, shows a largenumber of pairs that could be explained by the complex geometry of the CS.Accept (01-Sep-2023). [
DOI ]
[4] M. V., Sazhina O. S., Shatskiy A. A. «Geodesics in the wormhole gravitational field» //
Journal of Experimental and Theoretical Physics. — 2022. — Vol. 135, no. 1. — P. 81–90. The structure of spacetime near a wormhole (WH) and possible observational consequences areinvestigated theoretically. In connection with the growing accuracy of observations and the prospects of a newgravitational-wave channel, the problem of distinguishing between astrophysical manifestations of blackholes (BHs) and hypothetical WHs is becoming relevant. WHs, along with BHs, naturally arise within generalrelativity (GR). Observational searches for WHs require knowledge of the characteristic trajectories of bodiesin its vicinity, including the trajectories entering its throat. Equations of motion of a test particle in the WHmetric are derived, and the most interesting properties of these motions are considered. A general equationof geodesics in the WH metric is derived, and some properties of these geodesics are considered. The exactsolution for circular orbits of test particles around a WH, as well as an approximate analytical solution of thegeodesic equations, is analyzed. The shift of the pericenter of the orbit of a test particle in the WH field is considered,and possible observational consequences are discussed. Examples of test particle trajectories near aWH are presented that are obtained by numerical simulation. [
DOI ]
[5] O. S., Bulygin I. I., Cherepashchuk A. M. «Investigation of spectral characteristics and statistical properties of flicker noise of the x-ray nova a0620-00» //
Astronomy Reports. — 2021. — Vol. 65, no. 9. — P. 839–863. [
DOI ]
[6] M. V., Sazhina O. S. «Space fabric wrinkles. history of observational searches for exotic structures in the universe» //
Rivista del Nuovo Cimento della Societa Italiana di Fisica. — 2021. — P. 1–55. The paper consistently presents the history and methodology of observational searches for cosmic strings of various nature. Cosmic strings are one-dimensional extended objects predicted by modern cosmology, which, however, have not yet been detected with a high degree of confidence. The presence of cosmic strings changes the global geometry of the Universe and could serve as a unique proof of higher-dimensional theories. The properties and features of these cosmological objects from the point of view of observational astronomy are discussed. The presentation is preceded by a brief mathematical theory of cosmic strings. [
DOI ]
[7] A. D. Dolgov, A. G. Kuranov, N. A. Mitichkin et al. «On mass distribution of coalescing black holes» //
Journal of Cosmology and Astroparticle Physics. — 2020. — no. 12. — P. 017. [
DOI ]
[8] V. K. Milyukov, I. Y. Vlasov, M. V. Sazhin et al. «Relativistic reductions in high-precision measurements of the earth’s global gravity field using a multipair constellation» //
Astronomy Reports. — 2020. — Vol. 64, no. 5. — P. 447–457. The theory of relativistic reductions for future challenges of space gravimetry with target accuracyof up to 1 picometer is developed in this paper. [
DOI ]
LIST OF MAIN PUBLICATIONS (2000 – 2019)[1] O. S. Sazhina, D. Scognamiglio, M. V. Sazhin, and M. Capaccioli, “Optical analysis of a cmb cosmic string candidate,”
Monthly Notices of the Royal Astronomical Society, vol. 485, no. 2, pp. 1876–1885, 2019. [
DOI ]
[2] A. V. Morgunova and O. S. Sazhina, “The use of nonparametric methods of mathematical statistics to search for cosmic strings,”
Moscow University Physics Bulletin, vol. 74, no. 5, pp. 529–536, 2019. [
DOI ]
[3] M. V. Sazhin, V. E. Zharov, V. K. Milyukov, M. S. Pshirkov, V. N. Sementsov, and O. S. Sazhina, “Space navigation by x-ray pulsars,”
Moscow University Physics Bulletin, vol. 73, no. 2, pp. 141–153, 2018. [
DOI ]
[4] O. S. Sazhina and A. I. Mukhaeva, “Observational constraints on cosmological superstrings,”
Theoretical Physics (TP) Isaac Scientific Publishing, vol. 2, no. 2, pp. 70–78, 2017. [
DOI ]
[5] M. V. Sazhin, O. S. Sazhina, V. N. Sementsov, M. N. Siversky, V. E. Zharov, and K. V. Kuimov, “A multipole analysis of the apparent motion of reference radio sources,”
Moscow University Physics Bulletin, vol. 71, no. 3, pp. 304–311, 2016. [
DOI ]
[6] M. Capaccioli, M. V. Sazhin, and O. S. Sazhina, “De rerum natura now: alla scoperta della materia oscura,”
Il Nuovo Saggiatore, vol. 32, no. 3-4, 2016.
[7] O. S. Sazhina and A. I. Mukhaeva, “Observational constraints on cosmological superstrings,”
arXiv:1603.04008, 2016.
[8] M. V. Sazhin and O. S. Sazhina, “The scale factor in a universe with dark energy,”
Astronomy Reports, vol. 60, no. 4, pp. 425–437, 2016. [
DOI ]
arXiv: 1106.5478v1 [9] I. Y. Vlasov, O. S. Sazhina, V. N. Sementsov, and M. V. Sazhin, “Binary stars as sources of monochromatic gravitational waves,”
Astronomy Reports, vol. 59, no. 6, pp. 525–541, 2015. [
DOI ]
[10] M. V. Sazhin and O. S. Sazhina, “Search for cosmic strings,”
Astronomy Reports, vol. 59, no. 7, pp. 639–644, 2015. [
DOI ]
[11] O. S. Sazhina, V. N. Sementsov, and N. T. Ashimbaeva, “Cosmic string detection in radio surveys,”
Astronomy Reports, vol. 58, no. 1, pp. 16–29, 2014. [
DOI ]
[12] O. S. Sazhina, D. Scognamiglio, and M. V. Sazhin, “Observational constraints on the types of cosmic strings,”
European Physical Journal C, vol. 74, no. 8, p. 2972, 2014. [
DOI ]
[13] R. Consiglio, O. S. Sazhina, G. Longo, M. Sazhin, and F. Pezzella, “On the number of cosmic strings,”
Monthly Notices of the Royal Astronomical Society, vol. 439, no. 4, pp. 3213–3224, 2014. [
DOI ]
[13] O. S. Sazhina, “Probabilistic estimates of the number of cosmic strings,”
Journal of Experimental and Theoretical Physics, vol. 116, no. 1, pp. 71–79, 2013.
[15] A. O. Marakulin, O. S. Sazhina, and M. V. Sazhin, “Contribution from cosmological scalar perturbations to the angular velocity spectrum of extragalactic sources,”
Journal of Experimental and Theoretical Physics, vol. 115, no. 1, pp. 85–92, 2012.
[16] M. V. Sazhin, O. S. Sazhina, and M. S. Pshirkov, “Apparent motions of quasars due to microlensing,”
Astronomy Reports, vol. 55, no. 11, pp. 954–961, 2011.
[17] O. S. Sazhina and M. V. Sazhin, “Application of haar functions with cyclic translations in the search for cosmic strings,”
Moscow University Physics Bulletin, vol. 66, no. 6, pp. 588–592, 2011.
[18] O. S. Sazhina and M. V. Sazhin, “Cosmic strings in the universe: Achievements and prospects of research,”
Journal of Experimental and Theoretical Physics, vol. 113, no. 5, pp. 798–807, 2011.
[19] M. V. Sazhin, O. S. Sazhina, and A. O. Marakulin, “The spectrum of random icrf source angular velocities,”
Astronomy Reports, vol. 55, no. 11, pp. 945–953, 2011.
[20] M. V. Sazhin, O. S. Khovanskaya, M. Capaccioli, G. Longo, M. Paolillo, and G. Riccio, “Gravitational lens images generated by cosmic strings,”
The Open Astronomy Journal, vol. 3, pp. 200–206, 2010.
[21] V. E. Zharov, M. V. Sazhin, V. N. Sementsov, K. V. Kuimov, O. S. Sazhina, and N. T. Ashimbaeva, “Principles for selecting a list of reference radio sources for a celestial coordinate system,”
Astronomy Reports, vol. 54, no. 2, pp. 112–120, 2010. [
DOI ]
[22] M. V. Sazhin, I. Y. Vlasov, O. S. Sazhina, and S. G. Turyshev, “Radioastron: relativistic frequency change and time-scale shift,”
Astronomy Reports, vol. 54, no. 11, pp. 959–973, 2010.
[23] V. E. Zharov, M. V. Sazhin, V. N. Sementsov, K. V. Kuimov, O. S. Sazhina, and N. T. Ashimbaeva, “The celestial reference frame stability and apparent motions of the radio sources,” in
IAU Symposium, vol. 261 of
IAU Symposium, pp. 50–55, 2010. [
DOI ]
[24] M. V. Libanov, V. A. Rubakov, O. S. Sazhina, and M. V. Sazhin, “Cmb anisotropy induced by tachyonic perturbations of dark energy,”
Physical Review D, vol. 79, p. 083521, 2009.
[25] M. V. Libanov, V. A. Rubakov, O. S. Sazhina, and M. V. Sazhin, “Cmb anisotropy induced by tachyonic perturbations of dark energy,”
Journal of Experimental and Theoretical Physics, vol. 108, no. 2, pp. 226–235, 2009.
[26] M. V. Sazhin, V. N. Sementsov, V. E. Zharov, K. V. Kuimov, N. T. Ashimbaeva, and O. S. Sazhina, “Cosmological and kinematical criteria for the icrf2 sources selection,”
ArXiv e-prints, no. 0904.2146, pp. 1–25, 2009.
[27] M. V. Sazhin, V. N. Sementsov, V. E. Zharov, K. V. Kuimov, N. T. Ashimbaeva, and O. S. Sazhina, “Cosmological and kinematical criteria for the icrf2 sources selection,”
eprint arXiv:0904.2146, 2009.
[28] G. Covone, M. Paolillo, N. Napolitano, M. Capaccioli, G. Longo, J. P. Kneib, E. Jullo, J. Richard, O. S. Khovanskaya, M. V. Sazhin, N. A. Grogin, and E. Schreier, “Gauging the dark matter fraction in an l * s0 galaxy at z = 0.47 through gravitational lensing from deep hubble space telescope/advanced camera for surveys imaging,”
Astrophysical Journal, vol. 691, no. 1, pp. 531–536, 2009.
[29] V. E. Zharov, M. V. Sazhin, V. N. Sementsov, K. V. Kuimov, and O. S. Sazhina, “Physical origins for variations in the apparent positions of quasars,”
Astronomy Reports, vol. 53, no. 7, pp. 579–589, 2009. [
DOI ]
[30] G. Riccio, G. D’Angelo, M. V. Sazhin, O. S. Sazhina, G. Longo, and M. Capaccioli, “Simulations of cosmic strings signatures in the cmb,” in
FINAL WORKSHOP OF GRID PROJECTS, PON RICERCA, 1575, 2009.
[31] O. S. Sazhina, M. V. Sazhin, and V. N. Sementsov, “Cosmic microwave background anisotropy induced by a moving straight cosmic string,”
Journal of Experimental and Theoretical Physics, vol. 106, no. 5, pp. 878–887, 2008. [
DOI ]
[32] M. V. Sazhin, O. S. Khovanskaya, M. Capaccioli, G. Longo, M. Paolillo, G. Covone, N. A. Grogin, and E. J. Schreier, “Gravitational lensing by cosmic strings: what we learn from the csl-1 case,”
Monthly Notices of the Royal Astronomical Society, vol. 376, no. 4, pp. 1731–1739, 2007.
[33] M. Sazhin, M. Capaccioli, G. Longo, M. Paolillo, and O. Khovanskaya, “Further spectroscopic observations of the csl 1 object,”
Astrophysical Journal, vol. 636, pp. L5–L8, 2006.
[34] M. V. Sazhin, M. Capaccioli, G. Longo, M. Paolillo, O. S. Khovanskaya, N. A. Grogin, E. J. Schreier, and G. Covone, “The true nature of csl-1,”
eprint arXiv:astro-ph/0601494, pp. 1–5, 2006.
[35] M. Sazhin, M. Capaccioli, G. Longo, M. Paolillo, and O. Khovanskaya, “Further spectroscopic observations of the csl-1 object,”
Astrophysical Journal, vol. 636, pp. L5–L8, 2005.
[36] M. V. Sazhin and O. S. Khovanskaya, “The object csl-1 as an effect of projection,”
Astronomy Reports, vol. 49, no. 5, pp. 343–353, 2005. [
DOI ]
[37] M. V. Sazhin, M. Capaccioli, G. Longo, M. Paolillo, and O. S. Khovanskaya, “The true nature of csl-1,”
e-Print: astro-ph/0601494 (http://xxx.itep.ru/abs/astro-ph/0601494), 2005.
[38] M. V. Sazhin, O. S. Khovanskaya, M. Capaccioli, G. Longo, J. M. Alcala, R. Silvotti, and M. V. Pavlov, “Lens candidates in the capodimonte deep field in the vicinity of the csl1 object,”
eprint arXiv:astro-ph, no. 0406516, pp. 1–8, 2004.
[39] O. S. Khovanskaya, M. V. Sazhin, M. Capaccioli, and G. Longo, “Possible observation of a cosmic string,” in
Proceedings of the International Conference Wide Field Imaging from Space, Berkeley, California, USA, 2004.
[40] M. V. Sazhin, G. Sironi, and O. S. Khovanskaya, “Separation of foreground and background signals in single frequency measurements of the cmb polarization,”
New Astronomy, vol. 9, no. 2, pp. 83–101, 2004.
[41] M. Sazhin, G. Longo, M. Capaccioli, J. M. Alcalá, R. Silvotti, G. Covone, O. Khovanskaya, M. Pavlov, M. Pannella, M. Radovich, V. Testa, and V, “Csl-1: chance projection effect or serendipitous discovery of a gravitational lens induced by a cosmic string?,”
Monthly Notices of the Royal Astronomical Society, vol. 343, no. 2, pp. 353–359, 2003.
[42] S. O. Alexeyev, A. Barrow, G. Bowdole, M. V. Sazhin, and O. S. Khovanskaya, “A simple model for the evaporation of black holes at final stages,”
Astronomy Letters, vol. 28, pp. 428–433, 2002. [
DOI ]
[43] O. S. Khovanskaya, “Black holes in higher curvature gravity,” in
Gravitation and Cosmology Suppl, vol. 2 of
8, pp. 67–68, 2002.
[44] S. Alexeyev, A. Barrau, G. Boudoul, O. Khovanskaya, and M. Sazhin, “Black-hole relics in string gravity: last stages of hawking evaporation,”
Classical and Quantum Gravity, vol. 19, pp. 4431–4443, 2002. [
DOI ]
[45] S. O. Alexeyev, M. V. Sazhin, and O. S. Khovanskaya, “Parameters of the early universe and primordial black holes,”
Astronomy Letters, vol. 28, pp. 139–142, 2002. [
DOI ]
[46] S. O. Alexeyev and O. S. Khovanskaya, “Additional study of a restriction on the minimum black hole mass in string gravity,”
Gravitation and Cosmology, vol. 6, no. 1, pp. 14–18, 2000.