Deviations from the Flux-Recurrence Time Relationship in GS 1826-238: Potential Transient Spectral Changes

Abstract

The low-mass X-ray binary GS 1826-238 is presently unique for its consistently regular bursting behavior. In previous Rossi X-Ray Timing Explorer (RXTE) measurements between 1997 November and 2002 July, this source exhibited (nearly) limit-cycle bursts with recurrence times that decreased proportionately as the persistent flux increased. Here we report additional measurements of the burst recurrence time by RXTE, Chandra, and XMM-Newton, as well as observations of optical bursts. On a few occasions we measured burst recurrence times which deviated significantly from the earlier flux-recurrence time relationship, and most of these bursts occurred earlier than would be predicted based on the X-ray flux level. The epochs with early bursts were also accompanied by unusual broadband timing signatures, with the entire power spectrum shifting to higher frequencies. Concurrent XMM-Newton observations during one of these occasions, in 2003 April, indicate that an additional soft component may be present in the spectrum containing enough flux (30% of the total) to account for the burst recurrence time discrepancy. A self-consistent interpretation for the increase in soft flux and accompanying timing changes during 2003 April is that accretion disk extends down to smaller radial distances from the source than during the other observing epochs. The RXTE observations since 2003 April show that the spectral and timing properties have nearly returned to the previously established level.

10 pages, 9 figures, Accepted by ApJ

References in corpus (34)

• Advection-Dominated Accretion and the Spectral States of Black Hole X-Ray Binaries: Application to Nova Muscae 1991
• Modelling the behaviour of accretion flows in X-ray binaries
• Ultraluminous X-Ray Sources in External Galaxies
• Calibration of the Rossi X-ray Timing Explorer Proportional Counter Array
• A Unified Description of the Timing Features of Accreting X-ray Binaries
• Correlations in Quasi-Periodic Oscillation and Noise Frequencies Among Neutron-Star and Black-Hole X-ray Binaries
• The Chandra High Energy Transmission Grating: Design, Fabrication, Ground Calibration and Five Years in Flight
• Models for Type I X-Ray Bursts with Improved Nuclear Physics
• In-flight Performance of the High Energy X-ray Timing Experiment on the Rossi X-ray Timing Explorer
• The broad-band power spectra of X-ray binaries
• Are There Three Peaks in the Power Spectra of GX 339-4 and Cyg X-1?
• Hard X-ray Emission From Low Mass X-ray Binaries
• Propagation of thermonuclear flames on rapidly rotating neutron stars: extreme weather during type I X-ray bursts
• Rotational Evolution During Type I X-Ray Bursts
• Tracing the power-law component in the energy spectrum of black hole candidates as a function of the QPO frequency
• Six years of BeppoSAX Wide Field Cameras observations of nine galactic type-I X-ray bursters
• A multi-Lorentzian timing study of the atoll sources 4U 0614+09 and 4U 1728-34
• Periodic Thermonuclear X-ray Bursts from GS 1826-24 and the Fuel Composition as a Function of Accretion Rate
• Models of Type I X-ray Bursts from GS 1826-24: A Probe of rp-Process Hydrogen Burning
• Multi-wavelength observations of the Galactic black hole transient 4U1543-47 during outburst decay: state transitions and jet contribution
• Bursts from GS 1826-238: a clocked thermonuclear flashes generator
• Fe XXV and Fe XXVI Diagnostics of the Black Hole and Accretion Disk in Active Galaxies: Chandra Time-Resolved Spectroscopy of NGC 7314
• The Galactic black hole transient H1743-322 during outburst decay: connections between timing noise, state transitions and radio emission
• Comprehensive Analysis of RXTE Data from Cyg X-1: Spectral Index-Quasi-Periodic Oscillation Frequency-Luminosity Correlations
• Energy Spectra and High Frequency Oscillations in 4U 0614+091
• A close look at the state transitions of Galactic black hole transients during outburst decay
• Time-dependent models of two-phase accretion discs around black holes
• Chandra and RXTE Spectra of the Burster GS 1826-238
• In-orbit performance of the XMM-Newton X-ray telescopes: images and spectra
• Discovery of a ~1 Hz quasi-periodic oscillation in the low-mass X-ray binary 4U 1746-37
• INTEGRAL and RXTE monitoring of GRS 1758-258 in 2003 and 2004. A transition from the dim soft state to the hard state
• Evidence for a 2 hr Optical Modulation in GS1826-24
• Non-Detection of Gravitationally Redshifted Absorption Lines in the X-ray Burst Spectra of GS 1826-24
• Thermonuclear Flame Spreading on Rapidly Spinning Neutron Stars: Indications of the Coriolis Force?

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