Characterizing a new class of variability in GRS 1915+105 with simultaneous INTEGRAL/RXTE observations

Abstract

We report on the analysis of 100 ks INTEGRAL observations of the Galactic microquasar GRS 1915+105. We focus on INTEGRAL Revolution number 48 when the source was found to exhibit a new type of variability as preliminarily reported in Hannikainen et al. (2003). The variability pattern, which we name $\xi$, is characterized by a pulsing behaviour, consisting of a main pulse and a shorter, softer, and smaller amplitude precursor pulse, on a timescale of 5 minutes in the JEM-X 3-35 keV lightcurve. We also present simultaneous RXTE data. From a study of the individual RXTE/PCA pulse profiles we find that the rising phase is shorter and harder than the declining phase, which is opposite to what has been observed in other otherwise similar variability classes in this source. The position in the colour-colour diagram throughout the revolution corresponds to State A (Belloni et al. 2000) but not to any previously known variability class. We separated the INTEGRAL data into two subsets covering the maxima and minima of the pulses and fitted the resulting two broadband spectra with a hybrid thermal--non-thermal Comptonization model. The fits show the source to be in a soft state characterized by a strong disc component below ~6 keV and Comptonization by both thermal and non-thermal electrons at higher energies.

Accepted for publication in A&A. 11 pages, 10 figures, 4 in colour. Original figures can be found at http://www.astro.helsinki.fi/~diana/grs1915_rev48. Author affiliations corrected

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Cited by in corpus (57)

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• The Physics of the 'Heartbeat' State of GRS 1915+105
• Patterns of energy-dependent variability from Comptonization
• Two Years of INTEGRAL monitoring of GRS 1915+105 Part 2: X-Ray Spectro-Temporal Analysis
• The MeV spectral tail in Cyg X-1 and optically-thin emission of jets
• Effects of the stellar wind on X-ray spectra of Cygnus X-3
• Near-infrared survey of High Mass X-ray Binary candidates
• Spectral variability in Cygnus X-3
• The nature of the hard state of Cygnus X-3
• Gamma-ray observations of the microquasars Cygnus X-1, Cygnus X-3, GRS 1915+105, and GX 339-4 with the Fermi Large Area Telescope
• AstroSat view of GRS 1915+105 during the Soft State: Detection of HFQPOs and estimation of Mass and Spin
• High-Frequency Quasi-Periodic Oscillations from GRS 1915+105
• Radiation Pressure and Mass Ejection in Rho-like States of GRS 1915+105
• Comparison of time/phase lags in the hard state and plateau state of GRS 1915+105
• The XMM-Newton View of GRS1915+105
• Wide-band view of High Frequency QPOs of GRS 1915+105 in 'softer' variability classes observed with AstroSat
• A Statistical Study on the Low-Frequency QPO Amplitude Spectrum and Amplitude in GRS 1915+105
• The INTEGRAL view on Black Hole X-ray Binaries
• Probing the Peculiar Behavior of GRS 1915+105 at Near-Eddington Luminosity
• Accretion Disc Wind Variability in the States of the Microquasar GRS 1915+105
• The complex behaviour of the microquasar GRS 1915+105 in the rho class observed with BeppoSAX. II: Time-resolved spectral analysis
• Exploring the Long-Term Evolution of GRS 1915+105
• A variable-frequency HFQPO in GRS 1915+105 as observed with Astrosat
• The complex behaviour of the microquasar GRS 1915+105 in the rho class observed with BeppoSAX. I: Timing analysis
• Integral/Ibis Census of the Sky Beyond 100 kev
• Unraveling the foretime of GRS 1915+105 using AstroSat observations: Wide-band spectral and temporal characteristics
• Study of timing evolution from non-variable to structured large-amplitude variability transition in GRS 1915+105 using AstroSat
• A Persistent Disk Wind in GRS 1915+105 with NICER
• AstroSat view of IGR J17091-3624 and GRS 1915+105: decoding the 'pulse' in the 'Heartbeat State'
• Revisiting Evidence of Chaos in X-ray Light Curves: The Case of GRS 1915+105
• Non-linear oscillator models for the X-ray bursting of the microquasar GRS 1915+105
• MAXI J1820+070 with NuSTAR II. Flaring during the hard to soft state transition with a long soft lag
• Stochastic variability in X-ray emission from the black hole binary GRS 1915+105
• Is the plateau state in GRS 1915+105 equivalent to canonical hard states?
• Comptonization efficiencies of the variability classes of GRS 1915+105
• Correlations between QPO frequencies and spectral parameters of GRS 1915+105 using AstroSat observations
• The evolution of the high-frequency variability in the black hole candidate GRS 1915+105 as seen by RXTE
• Properties of unique hard X-ray dips observed from GRS 1915+105 and IGR J17091-3624 and their implications
• A non-linear mathematical model for the X-ray variability classes of the microquasar GRS 1915+105 -- II: transition and swaying classes
• Mapping the X-ray variability of GRS1915+105 with machine learning
• Inner Disc Obscuration in GRS 1915+105 Based on Relativistic Slim Disc Model
• Evolution of Accretion Disc Geometry of GRS~1915+105 during its $\chi$ state as revealed by TCAF solution
• An Insight-HXMT view of the mHz quasi-regular modulation phenomenon in the black hole X-ray binary 4U 1630-47
• Using the bispectrum to probe radio X-ray correlations in GRS 1915+105
• A timing view of the heartbeat state of GRS 1915+105
• The disk wind in GRS 1915+105 as seen by Insight-HXMT
• A statistical analysis of the "heartbeat" behaviour of GRS 1915+105
• X-ray Spectral Analysis of the Steady States of GRS 1915+105
• Exploring the broadband spectral and timing characteristics of GRS 1915+105 with AstroSat and NICER observations
• A non-linear mathematical model for the X-ray variability classes of the microquasar GRS 1915+105 -- I: quiescent, spiking states and QPOs
• A new variability pattern in GRS 1915+105 with NICER and Insight-HXMT observations
• Discovery of a new flaring class in GRS 1915+105 using AstroSat
• Dimming GRS 1915+105 observed with NICER and Insight--HXMT
• Likely detection of magnetic field related LFQPO in the soft X-ray re-brightening of GRS~1915+105
• Similarities and Differences in Accretion Flow Properties between GRS 1915+105 and IGR J17091-3624: a Case Study
• QPOML: A Machine Learning Approach to Detect and Characterize Quasi-Periodic Oscillations in X-ray Binaries
• Light curve fingerprints: an automated approach to the extraction of X-ray variability patterns with feature aggregation -- an example application to GRS 1915+105