Search Publications
On the black hole masses in ultra-luminous X-ray sources
Zhou, Xin-Lin
Ultra-luminous X-ray sources (ULXs) are off-nuclear X-ray sources in nearby galaxies with X-ray luminosities ⩾ 1039 erg s-1. The measurement of the black hole (BH) masses of ULXs is a long-standing problem. Here we estimate BH masses in a sample of ULXs with XMM-Newton observations using two different mass indicators, the X-r…
Reprint of: Multiwavelength modeling the SED of supersoft X-ray sources III. RS Ophiuchi: The supersoft X-ray phase and beyond
Skopal, A.
I modeled the 14 Å-37 µ m SED of the recurrent symbiotic nova RS Oph during its supersoft source (SSS) phase and the following quiescent phase. During the SSS phase, the model SEDs revealed the presence of a strong stellar and nebular component of radiation in the spectrum. The former was emitted by the burning WD at highly super-Eddington r…
Suzaku observations of Fe K α line in some Magnetic Cataclysmic Variables
Eze, R. N. C.
We resolved the 6.4 keV, 6.7 keV and 7.0 keV Fe K α lines in 19 Magnetic Cataclysmic Variables (mCVs) observed with the Suzaku satellite. The 6.7 keV and 7.0 keV emission lines are typically created by collisional excitation in the vicinity of the white dwarf arising from the shock front. The 6.4 keV iron emission line in contrast is formed in equ…
Synchrotron emission model of gamma-ray pulsar PSR J2021+3651
Chkheidze, N.; Babyk, Iu.
In the present paper a self-consistent theory, interpreting the high energy gamma-ray and X-ray observations of pulsar PSR J2021+3651 performed by Fermi-LAT, XMM-Newton and Chandra space telescopes are considered. It is shown that the photon spectrum between 0.1 keV and 25 GeV can be well described by a power-law function with the spectral index Γ…
On the origin of the iron fluorescent line emission from the Galactic Ridge
Eze, R. N. C.
The Galactic Ridge X-ray Emission (GRXE) spectrum has strong iron emission lines at 6.4, 6.7, and 7.0 keV, each corresponding to the neutral (or low-ionized), He-like, and H-like iron ions. The 6.4 keV fluorescence line is due to irradiation of neutral (or low ionized) material (iron) by hard X-ray sources, indicating uniform presence of the cold …
Ultraviolet spectroscopic study of EU UMa and ST LMi from HST and IUE observations
Sanad, M. R.; Bobrowsky, M.
We present the first orbit-resolved ultraviolet spectroscopic observations of the two polar systems EU UMa and ST LMi obtained with the Hubble Space Telescope Faint Object Spectrograph (HST FOS) and International Ultraviolet Explorer (IUE) during their intermediate- and low-luminosity states in the period between 1982 and 2003. Different line prof…
On the origin of the Fe Kα emission line from intermediate polar EX Hyrae
Eze, R. N. C.; Esaenwi, S.
We present spectral analysis of intermediate polar EX Hya observed with Suzaku satellite on 18-07-2007 for 91 kilo seconds (ks). We model the spectrum with an absorbed thermal bremsstrahlung and three Gaussian lines for the Fe Kα line complex. We resolved the 6.4, 6.7, and 7.0 keV lines, each corresponding to the neutral (or low-ionized), He-like,…
Tentative insight into the multiplicity of the persistent dust maker WR 106 from X-ray observations
De Becker, M.
This paper presents the results of the analysis of the very first dedicated X-ray observation with XMM-Newton of WR 106. This carbon-rich WC9d Wolf-Rayet star belongs to the category of persistent dust makers (WCd stars). The issue of the multiplicity of these dust makers is pivotal to understand the dust formation process, and in this context X-r…
"Constant" eclipsing binary in the instability strip
Çakırlı, Ö.
The eclipsing binary OO Peg consist of two late-A type stars in circular orbit with a period of 2.985 days. I use the high-resolution spectroscopic and extensive light curves from the ASAS and Hipparcos survey to measure the physical properties of the system. Previous attempts to model the light and radial velocity curves of the system have met wi…
Absorption features in the quasar HS 1603 + 3820 II. Distance to the absorber obtained from photoionisation modelling
Różańska, A.; Hryniewicz, K.; Ebeling, H. +4 more
We present the photoionisation modelling of the intrinsic absorber in the bright quasar HS 1603 + 3820. We constructed the broad-band spectral energy distribution using the optical/UV/X-ray observations from different instruments as inputs for the photoionisation calculations. The spectra from the Keck telescope show extremely high CIV to HI ratio…