Insight-HXMT observation on 4U~1608--52: evidence of interplay between thermonuclear burst and accretion environments

Abstract

A type-I burst could influence the accretion process through radiation pressure and Comptonization both for the accretion disk and the corona/boundary layer of an X-ray binary, and vice versa. We investigate the temporal evolution of a bright photospheric radius expansion (PRE) burst of 4U 1608-52 detected by Insight-HXMT in 1-50 keV, with the aim of studying the interplay between the burst and persistent emission. Apart from the emission from the neutron star (NS) surface, we find the residuals both in the soft (<3 keV) and hard (>10 keV) X-ray band. Time-resolved spectroscopy reveals that the excess can be attributed to an enhanced pre-burst/persistent emission or the Comptonization of the burst emission by the corona/boundary layer. The Comptonization model is a convolution thermal-Comptonization model (thcomp in XSPEC) and the Comptonization parameters are fixed at the values derived from the persistent emission. We find, during the PRE phase, after the enhanced pre-burst/persistent emission or the Comptonization of the burst emission is removed, the NS surface emission shows a plateau, and then a rise until the photosphere touches down to the NS surface, resulting in a flux peak at that moment. We speculate that the findings above correspond to that the obscured lower part of the NS surface by the disk is exposed to the line of sight due to the inner disk evaporation by the burst emission. The consistency between the fa model and convolution thermal-Comptonization model indicates the interplay between thermonuclear bursts and accretion environments. These phenomena did not usually show up by the conventional blackbody model fitting, which may be due to low count rate and narrow energy coverage in previous observations.

arXiv commentApJ in press. arXiv admin note: text overlap with arXiv:2208.12124, arXiv:1910.08220

References in corpus (38)

• On the Absorption of X-rays in the Interstellar Medium
• Modelling the behaviour of accretion flows in X-ray binaries
• Thermonuclear (type-I) X-ray bursts observed by the Rossi X-ray Timing Explorer
• Optimal binning of X-ray spectra and response matrix design
• The enhanced X-ray Timing and Polarimetry mission - eXTP
• Overview to the Hard X-ray Modulation Telescope (Insight-HXMT) Satellite
• An Empirical Background Model for the NICER X-ray Timing Instrument
• Boundary layer, accretion disk and X-ray variability in luminous LMXBs
• Spectral and temporal properties of Compton scattering by mildly relativistic thermal electrons
• Evidence for accretion rate change during type I X-ray bursts
• The Multi-INstrument Burst ARchive (MINBAR)
• X-ray bursting neutron star atmosphere models: spectra and color corrections
• X-ray bursting neutron star atmosphere models using an exact relativistic kinetic equation for Compton scattering
• The effect of accretion on the measurement of neutron star mass and radius in the low-mass X-ray binary 4U 1608-52
• Spectra of the spreading layers on the neutron star surface and constraints on the neutron star equation of state
• Evidence for enhanced persistent emission during sub-Eddington thermonuclear bursts
• The Evolution of the Accretion Disk around 4U 1820-30 During a Superburst
• Accretion disks and coronae in the X-ray flashlight
• Millisecond Oscillations and Photospheric Radius Expansion in Thermonuclear X-Ray Bursts
• Three-Layered Atmospheric Structure in Accretion Disks Around Stellar-Mass Black Holes
• Systematic Uncertainties in the Spectroscopic Measurements of Neutron-Star Masses and Radii from Thermonuclear X-ray Bursts. I. Apparent Radii
• A bright thermonuclear X-ray burst simultaneously observed with Chandra and RXTE
• Thermonuclear X-ray Bursts: Theory vs. Observations
• NICER Observes the Effects of an X-Ray Burst on the Accretion Environment in Aql X-1
• A NuSTAR observation of disk reflection from close to the neutron star in 4U 1608-52
• Type-I X-ray bursts reveal a fast co-evolving behavior of the corona in an X-ray binary
• X-Raying an Accretion Disk in Realtime: the Evolution of Ionized Reflection during a Superburst from 4U 1636-536
• Insight-HXMT observations of 4U~1636-536: Corona cooling revealed with single short type-I X-ray burst
• The Bursting Behavior of 4U 1728-34: Parameters of a Neutron Star and Geometry of a NS-disk system
• NICER Detection of Strong Photospheric Expansion during a Thermonuclear X-Ray Burst from 4U 1820-30
• X-ray bursts as a probe of the corona: the case of XRB 4U 1636-536
• On the nature of the flux variability during an expansion stage of a type I X-ray burst: Constraints on Neutron Star Parameters for 4U 1820-30
• Accretion heated atmospheres of X-ray bursting neutron stars
• Suzaku spectroscopy of the neutron star transient 4U 1608-52 during its outburst decay
• Burst-induced coronal cooling in GS 1826-24 The clock wagging its tail
• Effects of thermonuclear X-ray bursts on non-burst emissions in the soft state of 4U 1728--34
• Escape, capture, and levitation of matter in Eddington outbursts
• Variable spreading layer in 4U 1608-52 during thermonuclear X-ray bursts in the soft state

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• Return of 4U~1730--22 after 49 years silence: the peculiar burst properties of the 2021/2022 outbursts observed by Insight-HXMT
• Tracing the outburst decay of soft X-ray transients Aql X-1 and 4U 1608-52 with XSPECT
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