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arXiv · 0711.0328

Intermediate long X-ray bursts from the ultra-compact binary source SLX 1737-282

M. Falanga·J. Chenevez·A. Cumming·E. Kuulkers·G. Trap·A. Goldwurm
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Abstract

Aims: The low persistent X-ray burster source SLX 1737-282 is classified as an ultra-compact binary candidate. We compare the data on SLX 1737-282 with the other similar objects and attempt to derive constraints on the physical processes responsible for the formation of intermediate long bursts. Methods: Up to now only three intermediate long bursts, all with duration between ~15-30 minutes, have been recorded for SLX 1737-282. The properties of two intermediate long X-ray bursts observed by INTEGRAL from SLX 1737-282 are investigated. The broadband spectrum of the persistent emission in the 3-100 keV energy band is studied with the INTEGRAL data. Results: The persistent emission is measured to be < 1% Eddington luminosity. From the photospheric radius expansion observed during the bursts we derive the source distance at 7.3 kpc. The observed intermediate long burst properties from SLX 1737-282 are consistent with helium ignition at the column depth of 7-8 x 10E-9 g cm-2 and a burst energy release of 1E41 erg. The apparent recurrence time of ~80 days between the intermediate long bursts from SLX 1737-282 suggests a regime of unstable burning of a thick, pure helium layer slowly accreted from a helium donor star.

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M. Falanga, J. Chenevez, A. Cumming, E. Kuulkers, G. Trap, A. Goldwurm. 2008-03-31. Intermediate long X-ray bursts from the ultra-compact binary source SLX 1737-282. https://doi.org/10.1051/0004-6361:20078982

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