113 citations · 418 across the 29 of their papers we have counts for
31 papers
Probing the wind and evolutionary state of the quiescent luminous blue variable Var2 in the Galaxy M33: constraints from self-consistent non-LTE modeling
A. Kostenkov, Y. Solovyeva, E. Dedov +2
Luminous Blue Variables (LBVs) are massive stars with extreme luminosities, exhibiting significant irregular photometric and spectroscopic variability. This paper is dedicated to t…
On the spatial distribution of luminous blue variables in the M33 galaxy
A. Kostenkov, S. Fabrika, A. Kaldybekova +6
In the current paper, we present a study of the spatial distribution of luminous blue variables (LBVs) and various LBV candidates (cLBVs) with respect to OB associations in the M33…
The Nature of the Emission Spectrum of NGC 7793 P13: modeling the atmosphere of the donor star
A. S. Vinokurov, A. E. Kostenkov, K. E. Atapin +1
We continue to study the ultra-luminous X-ray source NGC 7793 P13 in the optical range. In this work, we are testing the model of a spherically symmetric wind atmosphere of the don…
Discovery of An X-ray Photoionized Optical Nebula and A Radio Nebula Associated with the ULX NGC 4861 X-1
Hang Gong, Ryan Urquhart, Alexandr Vinokurov +5
We have conducted long-slit spectroscopic observations and analyzed archival radio data for the ultraluminous X-ray source (ULX) NGC 4861 X-1. Our spectral line analysis unveils th…
Optical Counterparts of Two Candidate Ultraluminous X-ray Sources in NGC 4536
H. Avdan, E. Sonbas, K. S. Dhuga +7
Archival {\it XMM-Newton}, {\it Chandra} and {\it Hubble Space Telescope (HST)} data have been used to study the X-ray and optical properties of two candidate ultraluminous X-ray s…
Confirmation of the star J004229.87+410551.8 in M31 as a B[e] supergiant
Sarkisyan A., Vinokurov A., Solovyeva Yu. +4
We study the luminous blue variable candidate J004229.87+410551.8 in the Andromeda Galaxy. Earlier, the star displayed a spectral anomaly: although a hot emission spectrum had been…
Wind parameters of the new LBV in NGC1156
Y. Solovyeva, A. Kostenkov, E. Dedov +1
In this work we present the spectrum modeling results for the newly discovered luminous blue variable (LBV) in the NGC 1156 galaxy. Extended atmosphere models were calculated using…
Search for LBVs in the Local Volume galaxies: study of four stars in NGC 4449
Y. Solovyeva, A. Vinokurov, A. Sarkisyan +8
We continue to search for LBV stars in galaxies outside the Local Group. In this work, we have investigated four luminous stars in NGC 4449. Multiple spectral observations carried…
Search for LBVs in the Local Volume galaxies: study of two stars in NGC 1156
Y. Solovyeva, A. Vinokurov, N. Tikhonov +7
We continue the search for luminous blue variables (LBVs) in Local Volume galaxies in order to study their fundamental parameters. In this paper, we report the discovery of two new…
Simultaneous X-ray/UV observations of ultraluminous X-ray source Holmberg II X-1 with Indian space mission AstroSat
A. Vinokurov, K. Atapin, O. P. Bordoloi +11
We present the results of 8 epochs of simultaneous UV and X-ray observations of the highly variable ultraluminous X-ray source (ULX) Holmberg II X-1 with AstroSat -- Indian multiwa…
Periodic variability of the z=2.0 quasar QSO B1312+7837
M. Minev, V. D. Ivanov, T. Trifonov +6
We report here the first results from a 15-yr long variability monitoring of the z=2.0 quasar QSO B1312+7837. It shows luminosity changes with a period P~6.13 yr (P~2.04 yr at rest…
New data for the LBV in NGC 4736
Y. Solovyeva, A. Vinokurov, A. Kostenkov +3
We present new spectral and photometric data of confirmed LBV star from the NGC4736 galaxy. The star NGC4736_1 (Mbol = -11.5 mag) showed noticeable spectral variability from 2015 t…
The Transient Ultra-luminous X-ray Source, ULX-4, in M51
S. Allak, A. Akyuz, İ. Akkaya Oralhan +6
We present the results of a temporal and spectral analysis of the transient source ULX-4 in the galaxy M51. The data used were drawn from Chandra, XMM-Newton and Swift-XRT archives…
Ultraluminous X-Ray Sources
S. N. Fabrika, K. E. Atapin, A. S. Vinokurov +1
Ultraluminous X-ray sources (ULXs) were identified as a separate class of objects in 2000 based on data from the Chandra X-Ray Observatory. These are unique objects: their X-ray lu…
Optical Counterparts of ULXs in Two Dwarf Galaxies: NGC 4861 and NGC 4449
M. Ozdogan Ela, A. Akyuz, N. Aksaker +7
We present the results of a search for optical candidates of Ultraluminous X-ray sources (ULXs) in two dwarf galaxies: NGC 4861 and NGC 4449 using Hubble Space Telescope {\it HST}…
NGC 5474 X-1: a neutron star ULX in an old stellar cluster?
Kirill Atapin, Alexander Vinokurov, Arkadiy Sarkisyan +4
We present the optical and X-ray study of the ultraluminous X-ray source (ULX) NGC 5474 X-1. The X-ray spectrum taken during the bright state of the source ($L_X \sim 2\times10^{40…
Determining parameters of ULXs with model grids of extended atmospheres
A. Kostenkov, A. Vinokurov, Y. Solovyeva
In current work we continued study of wind parameters of ultraluminous X-ray sources (ULXs) using model grids of extended atmospheres. We present sets of models with temperatures f…
Observations of ultraluminous X-ray sources with the 6-m telescope of the SAO RAS
A. Vinokurov, K. Atapin, Y. Solovyeva +2
The nature of ultraluminous X-ray sources (ULXs) is not yet fully understood but it can be done in the most efficient way by analyzing its optical emission and environment. We pres…
Luminous Blue Variable candidates in M31
A. Sarkisyan, O. Sholukhova, S. Fabrika +7
We study five Luminous Blue Variable (LBV) candidates in the Andromeda galaxy and one more (MN112) in the Milky Way. We obtain the same-epoch near-infrared (NIR) and optical spectr…
New luminous blue variable candidates in the NGC 247 galaxy
Y. Solovyeva, A. Vinokurov, A. Sarkisyan +6
We search for LBV stars in galaxies outside the Local Group. Here we present a study of two bright sources in the NGC 247 galaxy. Object j004703.27-204708.4 ($M_V=-9.08 \pm 0.…
Modeling of extended atmospheres with temperatures below 40000K
A. Kostenkov, A. Vinokurov, Y. Solovyeva +2
We calculate models of extended stellar atmospheres with a temperature in the range of 12000-40000K and a mass loss rate of yr. A large number of…
Optical Counterpart to the Ultraluminous X-Ray Source in the UGC6456 Galaxy
Alexander Vinokurov, Kirill Atapin, Yulia Solovyeva
We report the identification of the optical counterpart to the transient ultraluminuos X-ray source in the blue dwarf galaxy UGC6456 (VII Zw 403). The source is highly variable in…
Optical Counterparts of ULXs and Their Host Environments in NGC 4490/4485
Senay Avdan, Aysun Akyuz, Alexander Vinokurov +6
We report the identification of the possible optical counterparts of five out of seven Ultraluminous X-ray Sources (ULXs) in NGC 4490/4485 galaxy pair. Using archival Hubble Space…
New Luminous Blue Variable Candidates in NGC 4736
Y. Solovyeva, A. Vinokurov, S. Fabrika +8
We have found three new LBV candidates in the star-forming galaxy NGC 4736. They show typical well-known LBV spectra, broad and strong hydrogen lines, He I lines, many Fe II lines,…