Zobrazeno 1 - 10
of 218
pro vyhledávání: '"A Kostenkov"'
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 donor star, previously identified as a B9 Ia supergiant. The model spectr
Externí odkaz:
http://arxiv.org/abs/2407.21117
Autor:
Avdan, H., Sonbas, E., Dhuga, K. S., Vinokurov, A., Göğüş, E., Avdan, S., Solovyeva, Y. N., Kostenkov, A. E., Shablovinskaya, E. S., Goktas, D.
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 sources (ULXs) in NGC\,4536. In order to search for potential optical c
Externí odkaz:
http://arxiv.org/abs/2303.12141
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 the non-LTE code CMFGEN. We have obtained the luminosity of the disco
Externí odkaz:
http://arxiv.org/abs/2209.06012
Autor:
Solovyeva, Y., Vinokurov, A., Sarkisyan, A., Kostenkov, A., Atapin, K., Fabrika, S., Oparin, D., Valeev, A., Bizyaev, D., Nedialkov, P., Spiridonova, O.
Publikováno v:
Monthly Notices of the Royal Astronomical Society, Volume 507, Issue 3, pp.4352-4366, 2021
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 out for J122810.94+440540.6, J122811.70+440550.9, and J122809.72+44051
Externí odkaz:
http://arxiv.org/abs/2208.05892
Autor:
Solovyeva, Y., Vinokurov, A., Tikhonov, N., Kostenkov, A., Atapin, K., Sarkisyan, A., Moiseev, A., Fabrika, S., Oparin, D., Valeev, A.
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 LBVs in the dwarf irregular galaxy NGC 1156. Both stars exhibit spect
Externí odkaz:
http://arxiv.org/abs/2208.05858
Autor:
Vinokurov, A., Atapin, K., Bordoloi, O. P., Sarkisyan, A., Kashyap, U., Chakraborty, M., Rahna, P. T., Kostenkov, A., Solovyeva, Y., Fabrika, S., Safonova, M., Gogoi, R., Sutaria, F., Murthy, J.
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 multiwavelength space satellite. During the entire observation period from la
Externí odkaz:
http://arxiv.org/abs/2205.05204
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 to 2018, which was accompanied by a significant change in the brightnes
Externí odkaz:
http://arxiv.org/abs/2109.05891
Autor:
Atapin, Kirill, Vinokurov, Alexander, Sarkisyan, Arkadiy, Solovyeva, Yulia, Medvedev, Aleksei, Fabrika, Sergei, Kostenkov, Alexander
We present an optical and X-ray study of the ultraluminous X-ray source NGC5474 X-1. From the analysis of the Chandra and Swift data we found that the source X-ray flux changed by more than 2 orders of magnitude within 3.5 years. In the bright state
Externí odkaz:
http://arxiv.org/abs/2011.00795
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 from 18000 up to 56000K as a line equivalent widths (EWs) and their rat
Externí odkaz:
http://arxiv.org/abs/2010.08399
Publikováno v:
MNRAS 496(2020) 5455-5462
MN112 is the Galactic luminous blue variable (LBV) candidate with circumstellar nebula. P Cygni is the first discovered LBV, which was recorded during major eruptions in the 17th century. The stars have similar spectra with strong emission hydrogen l
Externí odkaz:
http://arxiv.org/abs/2009.13463