INTERGAL detects a Type I X-ray burst from IGR J17498-2921

ATel #3560; C. Ferrigno, E. Bozzo, L. Gibaud (ISDC, Switzerland) A. Papitto (Univ. Cagliari, Italy) T. M. Belloni (INAF - Brera Observatory, Italy)
on 15 Aug 2011; 20:49 UT
Credential Certification: Carlo Ferrigno (Carlo.Ferrigno@unige.ch)

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We analyzed the JEM-X light curve (3-35 keV) of the newly discovered accreting millisecond pulsar IGR J17498-2921 (ATEL #3551, #3555, #3556, #3558, #3559) in the time interval from 2011-08-11 22:45 to 2011-08-14 13:41 to look for Type I X-ray bursts.

We used bins of 2 s and we searched for excesses of at least three standard deviations above the average flux, requiring a S/N of at least 3 for the highest bin.

During the 77.9 ks in which the source was in the instrument field of view, we found one event that matched these characteristics: it started on 2011-08-14 at 03:20:21 and lasted for about 15 s. The fit of the burst light curve with an exponential model yields a decay time of 6±2 s. The average burst spectrum can be described (χ²/d.o.f.=1.3/6) by a black body of temperature kT = 1.4±0.4 keV and radius 19⁺¹⁵_-8 km (assuming a distance of 10 kpc).