X-ray observations of accretion powered pulsars

İnam, Sıtkı Çağdaş
In this thesis, X-ray observations of four accretion powered pulsars are presented. Using RXTE observations of 4U 1907+09, we found three new pulse periods of the source. We found that the source spun-down almost at a constant rate of Þ


Avdan, H.; Avdan, S.; AKYÜZ, AYSUN; Balman, Şölen; AKSAKER, NAZIM; AKKAYA ORALHAN, Inci (American Astronomical Society, 2016-09-10)
We study the X-ray and optical properties of the ultraluminous X-ray source (ULX) X-6 in the nearby galaxy NGC 4258 (M106) based on the archival XMM-Newton, Chandra, Swift, and Hubble Space Telescope (HST) observations. The source has a peak luminosity of L-X similar to 2 x 10(39) erg s(-1) in the XMM-Newton observation of 2004 June. Consideration of the hardness ratios and the spectral model parameters shows that the source seems to exhibit possible spectral variations throughout the X-ray observations. In...
Ccd photometry and time series analysis of v2275 cyg and rw umi using data from the TUBITAK national observatory
Yılmaz, Mustafa Arda; Balman, Şölen; Department of Physics (2004)
In this work, we analyze the data from 1.5 m telescope of Tubitak National Observatory (TUG) for two objects V2275 Cyg and RW UMi. After applying aperture and PSF photometry to the CCD data, we derive the light curve of the objects. Also we apply discrete Fourier transform and Scargle time series analysis to obtain power spectrum and search for periodicities in their power spectra in which both systems show interesting properties. We discover large variations in V2275 Cyg due to irradiation effects on the s...
Vibrational stability of pre-main sequence stars
Burhan, Mehmet; Kızıloğlu, Nilgün; Department of Physics (2004)
In this study, vibrational properties and stability of delta-Scuti like pulsating pre-main sequence stars have been investigated. Studies were held in the mass range 2-4 Mo and limited to radial linear adiabatic pulsations. Numerical computations were performed by the oscillation program written by Kırbıyık & Al-Murad (1993). The models were selected to be at the latest phases of the pre-main sequence evolution where the luminosity starts to increase. We have limited our calculations upto the end of the rad...
The effect of rotation, up to second order, on the oscillation frequencies of some delta-scuti stars
Doğan, Gülnur; Kırbıyık, Halil; Department of Physics (2007)
In this work, the effect of rotation on the oscillation frequencies of some radially and nonradially oscillating Delta-Scuti stars have been explored. Rotation has been considered as a perturbation and treated up to the second order. Series of evolutionary models have been calculated for the oscillating stars in question and compared with the observational parameters. Three stars are considered: V350 Peg with no rotation, CC And with a rotational velocity Vsini=20 km/s, and BS Tuc with Vsini=130 km/s. We fi...
RXTE and Chandra observations of galactic microquasars GRO J1655-40 and GRS 1915+105
Bülbül, Gül Esra; Baykal, Altan; Department of Physics (2006)
In this thesis, RXTE timing analysis of Galactic Microquasars GRO J1655-40 and GRS 1915+105, the Chandra and RXTE joint spectral analysis of GRS 1915+105 are presented. We have investigated quasi periodic oscillations (QPOs) in the black hole binaries GRO J1655-40 and GRS 1915+105 observed in 99 and 122 observations made by the Proportional Counter Array (PCA) on board Rossi X-Ray Timing Explorer (RXTE) in both low energy band (2-12 keV) and high energy band (13-27 keV), respectively. Four different X-ray s...
Citation Formats
S. Ç. İnam, “X-ray observations of accretion powered pulsars,” Ph.D. - Doctoral Program, Middle East Technical University, 2004.