Rapid State Transitions in the Galactic Black Hole Candidate Source GRS 1915+105

Abstract

We examine the X-ray spectral and temporal behavior of the Galactic black hole candidate source GRS 1915+105 during its spectral state transition observed in 1997 March - August. The source was making a slow transition from a low-hard state to a high-soft state in about three months and during this transition it was exhibiting a series of fast variations which can be classified as bursts. During one type of bursts, called the irregular bursts, it was found that the source makes rapid transitions between two intensity states. We have analyzed the RXTE PCA data obtained on 1997 June 18 (when the source was making rapid state transitions) and compared the results with two sets of data each pertaining to the low hard-state and high-soft states. We find that the power density spectrum (PDS) during the burst shows remarkable similarity to that seen during the high-soft state of the source. The PDS during the quiescence, on the other hand, is quite flat and is very similar to the PDS commonly seen during the canonical low-hard state of black hole X-ray binaries. A low frequency QPO at $\sim$3 Hz is observed during the quiescence, a property seen during the low-hard state of the source. The X-ray spectrum of the source during quiescence is similar to the spectrum seen during the low-hard state of the source and the spectra during the burst and high-soft state are very similar to each other. These observations corroborate the suggestion made by Yadav et al. (1999) that during the irregular bursts the source shows spectral state variations at very fast time scales. We explain such fast state changes using the two component accretion flow model in which the accretion disk consists of a geometrically thin (and optically thick) standard disk co-existing with an advection dominated hot thick disk.

7 pages, 7 figures, Accepted in ApJ to appear in Dec. 1, 2000 issue

References in corpus (3)

• Correlation among QPO frequencies and Quiescence-state Duration in Black Hole Candidate GRS 1915+105
• Time-Dependent Disk Models for the Microquasar GRS1915+105
• Mass Outflow Rate From Accretion Discs around Compact Objects

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• Model for Relaxation Oscillations of Luminous Accretion Disk in GRS1915+105: Variable Inner Edge
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• Characterising anomalous transport in accretion disks from X-ray observations
• QPO frequencies and mass-outflow rates in black hole powered galactic microquasars
• Accreting corona model of the X-ray variability in soft state X-ray binaries and active galactic nuclei
• Fast Transition between High-soft and Low-soft States in GRS 1915+105: Evidence for a Critically Viscous Accretion Flow
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• Correlated radio:X-ray emission in the hard states of Galactic microquasars
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• Properties of unique hard X-ray dips observed from GRS 1915+105 and IGR J17091-3624 and their implications
• Interpreting the large amplitude X-ray variation of GRS 1915+105 and IGR J17091-3624 as modulations of an accretion disc
• A NuSTAR and Swift View of the Hard State of MAXI J1813-095
• Standing Shocks in Magnetized Dissipative Accretion Flow around Black Holes
• Evidence of variation of the accretion flow geometry in GRS 1915+105 from IXAE and RXTE data
• Broadband X-ray properties of black holes GRS 1758-258 and 1E 1740.7-2942: AstroSat and NuSTAR results
• A Study of the Variation of Geometry of Accretion Flows of Compact Objects through Timing and Spectral Analysis of Their Outbursts
• Searching for quantum-gravity footprint around stellar-mass black holes
• Rapid onset of a Comptonisation zone in the repeating tidal disruption event XMMSL2 J140446.9-251135
• X-Ray Bursts from the Galactic X-Ray Transient Source GRS 1915+105
• Spectral signature of mass outflow in Two Component Advective Flow Paradigm
• Inner Disk Oscillations and QPOs in Relativistic Jet Sources