Related papers: Multifrequency Observations of the Galactic Microq…
The Galactic microquasars GRS1915+105 and GRO J1655-40 were targets for dedicated monitoring programs with RXTE throughout 1996 and 1997. We review recent results with particular attention to the X-ray QPOs seen in these sources. We confirm…
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…
A new class of X-ray sources was clearly established with the discovery of highly relativistic radio jets from the galactic sources GRS 1915+105 and GRO J1655-40. Both of these objects have given us a broader view of black holes and the…
We report the discovery in archival Rossi X-ray Timing Explorer (RXTE) data of a 40 Hz quasiperiodic oscillation (QPO) in the hard X-ray flux from the galactic microquasar GRS 1915+105. The QPO is detected only in the hard X-ray band above…
We show that the galactic microquasar GRS 1915+105 exhibits quasi-periodic oscillations (QPOs) whose frequency varies continuously from 1-15 Hz, during spectrally hard dips when the source is in a flaring state. We report here analyses of…
We report on the timing analysis of RXTE observations of the Galactic micro-quasar GRS 1915+105 performed in 2003. Out of a total of six times ~20 ks, we focus here only on the three observations during which GRS 1915+105 is found in a…
We analyze a set of three RXTE Target of Opportunity observations of the Galactic microquasar GRS 1915+105, observed on April 2000, during a multi-wavelength campaign. During the three observations, a strong, variable low frequency (2-9 Hz)…
We analyzed two 1996 observations of the Galactic Microquasar GRS 1915+105 taken with the Proportional Counter Array on board the Rossi X-ray Timing Explorer. We focus on the properties of the high-frequency QPO as a function of the `dip'…
The results of X-ray observations of Galactic superluminal jet source GRS 1915+105 during its low luminosity state and state transitions in October, 1996 - April, 1997 with PCA and HEXTE instruments aboard Rossi X-ray Timing Explorer (RXTE)…
We report the discovery with the proportional counter array (PCA) onboard the Rossi X-ray Timing Explorer (RXTE) of a 450 Hz quasiperiodic oscillation (QPO) in the hard X-ray flux from the galactic microquasar GRO J1655-40. This is the…
From data obtained from the PCA in the 2-11 keV and 11-30.5 keV energy range, GRS 1915+105 is seen during RXTE observations between 1996 May and October on two separate branches in a hardness intensity diagram. On the hard branch, GRS…
We analyse a set of three RXTE Target of Opportunity observations of the Galactic microquasar GRS 1915+105, observed in April 2000. We concentrate on the timing properties of the source, and examine the properties of a low frequency QPO,…
Powerful relativistic jets are one of the ubiquitous features of accreting black holes in all scales. GRS 1915+105 is a well-known fast-spinning black-hole X-ray binary with a relativistic jet, termed as a ``microquasar'', as indicated by…
The superluminal X-ray transient source GRS 1915+105 was observed during July 20-29, 1996 with the Indian X-ray Astronomy Experiment (IXAE) on the Indian satellite IRS-P3 launched on March 21, 1996 from Shriharikota Range in India. During…
We measured the phase-lag spectrum of the high-frequency quasi-periodic oscillations (QPO) in the black hole systems (at QPO frequencies) GRS 1915+105 (35 Hz and 67 Hz), GRO J1655-40 (300 Hz and 450 Hz), XTE J1550-564 (180 Hz and 280 Hz),…
We present the results of the timing analysis of five Rossi X-ray Timing Explorer observations of the Black Hole Candidate GRS 1915+105 between 1996 September and 1997 December. The aim was to investigate the possible presence of a type-B…
The properties of sub-second time variability of the X-ray emission of the black-hole binary GRS 1915+105 are very complex and strictly connected to its patterns of variability observed on long time scales. A key aspect for determining the…
Excellent coverage of the entire 16-month 1996-97 outburst cycle of GRO J1655-40 was provided by RXTE. We present a full spectral analysis of these data, which includes 52 PCA spectra from 2.5-20 keV and HEXTE spectra above 20 keV. We also…
This is the first of two papers in which we address the physics of the low-frequency Quasi-Periodic Oscillation (QPO) of X-ray binaries, in particular those hosting a black hole. We discuss and repeat the recent analysis and spectral…
We present a study of the properties of strong 0.8-3.0 Hz quasi-periodic oscillations (QPOs) that occurred during 1997 RXTE observations of the microquasar GRS 1915+105 in the low-hard state. The high count rates allow us to track…