Related papers: Kilohertz QPO Frequency and Flux Decrease in AQL X…
We present the first broadband spectral and timing study of the Be/X-ray pulsar XTE J0111.2$-$7317 (SXP31.0) during the first major outburst since its discovery in 1998. This giant type II outburst, observed between April and September…
The recurrent soft X-ray transient Aquila X-1 was observed with Suzaku for a gross duration of 79.9 ks, on 2011 October 21 when the object was in a rising phase of an outburst. During the observation, the source exhibited a clear spectral…
We study the temporal and energy spectral characteristics of the persistent black hole X-ray binary LMC X-1 using two XMM-Newton and a Suzaku observation. We report the discovery of low frequency (~ 26-29 mHz) quasi-periodic oscillations…
Type--I thermonuclear bursts (TNBs) from neutron star low-mass X-ray binaries (NS LMXBs) originate on the neutron star's surface from the unstable burning of the accreted material. On the other hand, kHz quasi-periodic oscillations (QPOs)…
We report the discovery ($20\sigma$) of kilohertz quasi-periodic oscillations (kHz QPOs) at ~ 690 Hz from the transient neutron star low-mass X-ray binary EXO 1745-248. We find that this is a lower kHz QPO, and systematically study the time…
We investigate the behavior of the high frequency quasi-periodic oscillations (QPOs) in 4U 0614+091, combining timing and spectral analysis of RXTE observations. The energy spectra of the source can be described by a power law (alpha ~ 2.8)…
We report on a detailed analysis of the so-called ~1 Hz quasi-periodic oscillation (QPO) in the eclipsing and dipping neutron-star low-mass X-ray binary EXO 0748-676. This type of QPO has previously been shown to have a geometric origin.…
We present the results of timing analysis of the low-frequency Quasi-Periodic Oscillation (QPO) in the Rossi X-Ray Timing Explorer data of the black hole binary XTE J1550--564 during its 1998 outburst. The QPO frequency is observed to vary…
An outburst of the X-ray transient source XTE J1806--246 (2S1803--245) has been observed by Rossi X-ray Timing Explorer in April-July 1998. Strong quasi-periodical oscillations (QPO) with a central peak frequency around 9 Hz was detected in…
We have analyzed data obtained during two observations with the Rossi X-ray Timing Explorer on January 5 and 8, 1997, of the low-mass X-ray binary (LMXB) and atoll source 4U 1636-53. We measure the frequency separation of the two…
Pairs of quasi-periodic oscillations (QPOs) at kilohertz frequencies are a common phenomenon in several neutron-star low-mass X-ray binaries. The frequency separation of the QPO peaks in the pair appears to be constant in many sources and…
We study systematically the ~0.1-1200 Hz quasi-periodic oscillations (QPOs) and broad noise components observed in the power spectra of non-pulsing neutron-star and black-hole low-mass X-ray binaries. We show that among these components we…
Our goal is to investigate the X-ray timing and spectral variability of the high-mass X-ray binary 1A 1118-615 during a type-II outburst. We performed a detailed color, spectral and timing analysis of a giant outburst from 1A 1118-615,…
We present the results of an extensive timing analysis of the 1999 outburst of the soft X-ray transient and black hole candidate XTE J1859+226 as observed with the Rossi X-Ray Timing Explorer. Three main different types of low frequency…
We study the dependence of kHz quasi-periodic oscillation (QPO) frequency on accretion-related parameters in the ensemble of neutron star low-mass X-ray binaries. Based on the mass accretion rate, $\dot{M}$, and the magnetic field strength,…
We report the discovery of a kilohertz quasi-periodic oscillation (kHz QPO) in the low-mass X-ray binary (LMXB) 2S 0918-549. The kHz QPO has a frequency of 1156+-9 Hz, a FWHM of 70+-20 Hz, and a fractional rms amplitude of 18%+-2%. We also…
We have investigated 52 RXTE pointed observations of GRO J1655-40 spanning the X-ray outburst that commenced on 1996 April 25 and lasted for 16 months. Our X-ray timing analyses reveal four types of QPOs: three with relatively stable…
We report on X-ray and soft gamma-ray observations of the black-hole candidate GX 339-4 during its 2007 outburst, performed with the RXTE and INTEGRAL satellites. The hardness-intensity diagram of all RXTE/PCA data combined shows a q-shaped…
We report the first clear evidence for the simultaneous presence of a low frequency break and a QPO in the fluctuation power spectrum of a well known ultraluminous X-ray source (ULX) in M82 using long XMM-Newton observations. The break…
We have carried out a systematic study of the properties of the kilo-Hertz quasi-periodic oscillations (QPO) observed in the X-ray emission of the neutron star low-mass X-ray binary 4U1608-52, using archival data obtained with the Rossi…