Broadband time-resolved spectroscopy of thermonuclear X-ray bursts from 4U 1636-536 using AstroSat

Abstract

Broadband spectral studies of Type-I X-ray bursts can put strong constraints on the physics of burst spectra as well as their interaction with the environment. We present the results obtained from the broadband time-resolved spectroscopy of 15 thermonuclear bursts detected simultaneously from the neutron star atoll source 4U 1636-536 using LAXPC and SXT onboard AstroSat. During the observations with AstroSat, the Low mass X-ray binary (LMXB) 4U 1636-536 is observed to show a modest spectral evolution within the island state. The broadband burst spectra are observed to show an excess in addition to the thermal emission from the neutron star surface near the peak of the bursts. We investigate the interpretation of the excess observed near the peak of the burst as re-emission/reprocessing of the photons by the accretion disk/corona or scattering of the photons in the neutron star atmosphere or the enhanced persistent emission due to Poynting-Robertson drag. This is the first reported broadband simultaneous study of Type-I bursts using LAXPC and SXT onboard AstroSat. This kind of study may provide a better understanding of the burst-accretion interaction and how the bursts influence the overall accretion process contributed by the accretion disk as well as the corona.

23 pages, 12 figures, 3 tables. Accepted for publication in MNRAS

References in corpus (11)

• Thermonuclear (type-I) X-ray bursts observed by the Rossi X-ray Timing Explorer
• X-ray bursting neutron star atmosphere models using an exact relativistic kinetic equation for Compton scattering
• X-ray time variability across the atoll source states of 4U 1636--53
• Evidence for enhanced persistent emission during sub-Eddington thermonuclear bursts
• Accretion disks and coronae in the X-ray flashlight
• X-ray Reflection and An Exceptionally Long Thermonuclear Helium Burst from IGR J17062-6143
• X-Raying an Accretion Disk in Realtime: the Evolution of Ionized Reflection during a Superburst from 4U 1636-536
• Thermonuclear X-ray Bursts with late secondary peaks observed from 4U 1608-52
• Thermonuclear X-ray bursts from LMXB 4U 1636$-$536 observed with AstroSat
• The study of multi-peaked type-I X-ray bursts in the neutron-star low mass X-ray binary 4U 1636$-$536 with RXTE
• Flux decay during thermonuclear X-ray bursts analysed with the dynamic power-law index method

Cited by in corpus (4)

• NICER observations of the evidence of Poynting-Robertson drag and disk reflection during type I X-ray bursts from 4U 1636$-$536
• Burst-Disk Interaction in 4U 1636-536 as observed by NICER
• The thermonuclear X-ray bursts of 4U 1730-22
• Broadband spectro-temporal investigation of neutron star low-mass X-ray binary GX 349+2