X-ray Reflection and An Exceptionally Long Thermonuclear Helium Burst from IGR J17062-6143

Abstract

Thermonuclear X-ray bursts from accreting neutron stars power brief but strong irradiation of their surroundings, providing a unique way to study accretion physics. We analyze MAXI/GSC and Swift/XRT spectra of a day-long flash observed from IGR J17062-6143 in 2015. It is a rare case of recurring bursts at a low accretion luminosity of 0.15% Eddington. Spectra from MAXI, Chandra, and NuSTAR observations taken between the 2015 burst and the previous one in 2012 are used to determine the accretion column. We find it to be consistent with the burst ignition column of 5x10^10 g cm^-2, which indicates that it is likely powered by burning in a deep helium layer. The burst flux is observed for over a day, and decays as a straight power law: F~t^-1.15. The burst and persistent spectra are well described by thermal emission from the neutron star, Comptonization of this emission in a hot optically thin medium surrounding the star, and reflection off the photoionized accretion disk. At the burst peak, the Comptonized component disappears, when the burst may dissipate the Comptonizing gas, and it returns in the burst tail. The reflection signal suggests that the inner disk is truncated at ~100 gravitational radii before the burst, but may move closer to the star during the burst. At the end of the burst, the flux drops below the burst cooling trend for 2 days, before returning to the pre-burst level.

16 pages, 10 figures, 6 tables, accepted for publication in ApJ

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Cited by in corpus (13)

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• Low Mass X-ray Binaries: The Effects of the Magnetic Braking Prescription
• A new radio census of neutron star X-ray binaries
• An Observationally-Derived Kick Distribution for Neutron Stars in Binary Systems
• Indications of non-conservative mass-transfer in AMXPs
• IGR J17062-6143 is an Accreting Millisecond X-ray Pulsar
• The Galactic LMXB Population and the Galactic Centre Region
• 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
• Evolution of accretion disc reflection spectra due to a Type I X-ray burst
• Broadband time-resolved spectroscopy of thermonuclear X-ray bursts from 4U 1636-536 using AstroSat
• The thermonuclear X-ray bursts of 4U 1730-22
• On the impact of an intermediate duration X-ray burst on the accretion environment in IGR J17062-6143