Chandra observations of the peculiar X-ray transient IGR J16358-4726

Abstract:

The new transient IGR J16358-4726 was discovered on 2003 March 19 with INTEGRAL. We detected the source serendipitously during our 2003 March 24 observation of SGR 1627 – 41 with the CHANDRA X-ray Observatory at the 1.7 × 10−10 ergs s−1 cm−2 flux level (2–10 keV) with a very high absorption column (NH=3.3×1023 cm−2) and a hard power law spectrum of photon index 0.5(1). We discovered a very strong flux modulation with a period of 5880(50) s and peak-to-peak pulse fraction of 70(6) % (2–10 keV), clearly visible in the x-ray data. The nature, however, of IGR 16357-4726 remains unresolved. Most likely, we are looking at a galactic binary neutron star system as evidenced by the detection of rest frame fluorescence line emission from neutral Fe K (6.4 keV) in the Chandra spectrum. If the detected modulation is a spin period, this transient is a new kind of object, belonging to a class of very hard …

Año de publicación:

2004

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