RXTE and Chandra observations of galactic microquasars GRO J1655-40 and GRS 1915+105

Bülbül, Gül Esra
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 states are seen in the combined characteristics of power spectra, light curves extracted by using All Sky Monitor (ASM) and spectra during 1996 and 2005. Timing analysis of RXTE observations of both of two black hole binaries GRO J1655-40 and GRS 1915+105 displays twin high frequency quasi periodic oscillations (QPOs) which are sometimes simultaneous in high energy band. It is also shown that the time averaged 30 ksec Chandra grating spectrum analysis and RXTE spectrum analysis of recent observation of GRS 1915+105 in the very high state are consistent with the parameters which were mentioned before. We briefly discussed our results and the models on black hole spin and mass.


RXTE and Swift Observations of SWIFT J0513.4-6547
Sahiner, S.; Serim, Muhammed Miraç; Baykal, Altan; İNAM, SITKI ÇAĞDAŞ (Oxford University Press (OUP), 2016-02-11)
We present timing and spectral analysis of Swift-XRT (X-ray Telescope) and RXTE-PCA (Rossi X-ray Timing Explorer-proportional Counter Array) observations of the transient Be/X-ray pulsar SWIFT J0513.4-6547 during its outburst in 2009 and its rebrightening in 2014. From 2009 observations, short-term spin-up rate of the source after the peak of the outburst is found to have about half of the value measured at the peak of the outburst by Coe et al. When the source is quiescent between 2009 and 2014, average sp...
Pulse frequency fluctuations of magnetars
Cerri-Serim, D.; Serim, Muhammed Miraç; Sahiner, S.; Inam, S. C.; Baykal, Altan (Oxford University Press (OUP), 2019-05-01)
Using RXTE, Chandra, XMM-Newton and Swift observations, we construct the power spectra and torque noise strengths of magnetars for the first time. For some of the sources, on time-scales of months to years, we measure strong red noise that might be a consequence of their outbursts. We compare the noise strengths of magnetars with those of radio pulsars by investigating the possible correlations of noise strength with spin-down rate, magnetic field and age. Using these correlations, we find that the noise st...
X-ray observations of accretion powered pulsars
İnam, Sıtkı Çağdaş; Baykal, Altan; Department of Physics (2004)
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
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...
Citation Formats
G. E. Bülbül, “RXTE and Chandra observations of galactic microquasars GRO J1655-40 and GRS 1915+105,” M.S. - Master of Science, Middle East Technical University, 2006.