A Strong X-Ray Burst from the Low Mass X-Ray Binary EXO0748-676

Abstract

We have observed an unusually strong X-ray burst as a part of our regular eclipse timing observations of the low mass binary system EXO0748-676. The burst peak flux was 5.2x10^-8 ergs cm^-2 s^-1, approximately five times the normal peak X-ray burst flux observed from this source by RXTE. Spectral fits to the data strongly suggest that photospheric radius expansion occurred during the burst. In this Letter we examine the properties of this X-ray burst, which is the first example of a radius expansion burst from EXO0748-676 observed by RXTE. We find no evidence for coherent burst oscillations. Assuming that the peak burst luminosity is the Eddington luminosity for a 1.4 solar mass neutron star we derive a distance to EXO0748-676 of 7.7 kpc for a helium-dominated burst photosphere and 5.9 kpc for a hydrogen-dominated burst photosphere.

15 pages including 2 figures and 1 table. Accepted for publication in the Astrophysical Journal

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Cited by in corpus (25)

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• EXO 0748-676 Rules out Soft Equations of State for Neutron Star Matter
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• Analysing the atolls: X-ray spectral transitions of accreting neutron stars
• Further X-ray observations of EXO 0748-676 in quiescence: evidence for a cooling neutron star crust
• State Transitions in Bright Galactic X-ray Binaries: Luminosities Span by Two Orders of Magnitude
• Biases for neutron-star mass, radius and distance measurements from Eddington-limited X-ray bursts
• Discovery of X-ray burst triplets in EXO 0748-676
• XMM-Newton observations of the low-mass X-ray binary EXO 0748-676 in quiescence
• Multiwavelength Observations of EXO 0748-676 - I. Reprocessing of X-ray Bursts
• Properties of the ionised plasma in the vicinity of the neutron-star X-ray binary EXO 0748-676
• Long tails on thermonuclear X-ray bursts from neutron stars: a signature of inward heating?
• Modelling the disk atmosphere of the low mass X-ray binary EXO 0748-676
• Discovery of millihertz quasi-periodic oscillations in the X-ray binary EXO 0748--676
• Levitating atmospheres of Eddington-luminosity neutron stars
• Suzaku Observation of the High-Inclination Binary EXO 0748-676 in the Hard State
• RXTE/ASM and Swift/BAT Observations of Spectral Transitions in Bright X-ray Binaries in 2005-2010
• The Quiescent Optical and Infrared Counterpart to EXO 0748-676 = UY Vol
• Astrophysics in 2006
• The cooling, mass and radius of the neutron star in EXO 0748-676 in quiescence with XMM-Newton
• The distance and internal composition of the neutron star in EXO 0748-676 with XMM-Newton
• Search for pulsations in the LMXB EXO 0748-676
• Simultaneous Optical and X-ray Detection of a Thermonuclear Burst in the 2024 Outburst of EXO 0748-676
• Comparing P-stars with Observations
• The orbital period and inclination of the neutron star X-ray transient MAXI J1807+132