Superburst with Outburst from EXO 1745-248 in Terzan 5 with MAXI

Abstract

MAXI/GSC detected a superburst from EXO 1745-248 in the globular cluster Terzan 5 on 2011 October 24. The GSC light curve shows an exponential decay with an e-folding time of 0.3 day. The spectra are consistent with the blackbody radiation, whose temperature is 2.2 keV and 1.2 keV at MJD 55858.56 and 55859.20, respectively. The fluence is $1.4\times 10^{42}$ erg in 2-20 keV assuming 8.7 kpc distance. The sphere radius of the blackbody and its luminosity are estimated to be 6.2 km and $1.1\times 10^{38}$ erg s${}^{-1}$, respectively, from the spectral fitting at the flux peak. Those e-folding time, temperature, softening, fluence, and radius are typical of superbursts from the low-mass X-ray binaries. The superburst was followed by an outburst 28 hours after the superburst onset. The outburst lasted for 5 days and the fluence was $4.3\times 10^{42}$ erg. The instability of the accretion disk caused by the superburst would be an explanation for the outburst, whereas the mass accretion of the matter evaporated from surface of the companion star by the superburst would be another possibility.

5 pages 4 figures

References in corpus (5)

• Gas Slit Camera (GSC) onboard MAXI on ISS
• In-Orbit Performance of MAXI Gas Slit Camera (GSC) on ISS
• Faint X-ray Sources in the Globular Cluster Terzan 5
• First superburst from a classical low-mass X-ray binary transient
• Highly coherent kilohertz quasi-periodic oscillations from a neutron star X-ray binary EXO 1745-248

Cited by in corpus (14)

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• Observational Constraints on Neutron Star Masses and Radii
• Accretion disks and coronae in the X-ray flashlight
• Discovery of the Third Transient X-ray Binary in the Galactic Globular Cluster Terzan 5
• Determining Neutron Star Properties by Fitting Oblate-Star Waveforms To X-ray Burst Oscillations
• A catalogue of unusually long thermonuclear bursts on neutron stars
• Maxi observations of long X-ray bursts
• An XMM-Newton and INTEGRAL view on the hard state of EXO 1745-248 during its 2015 outburst
• Extreme Quiescent Variability of the Transient Neutron Star Low-mass X-ray Binary EXO 1745-248 in Terzan 5
• Probing X-ray burst -- accretion disk interaction in low mass X-ray binaries through kilohertz quasiperiodic oscillations
• The energetic thermonuclear bursts in SAX J1712.6-3739
• Discovery of a strong 6.6 keV emission feature from EXO 1745$-$248 after the superburst in 2011 October
• Long thermonuclear burst driven thermal-viscous instability of accretion disk: triggering an outburst-like X-ray flare