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XMM-Newton observations of the INTEGRAL X-ray transient J17544-2619

R. Gonzalez-Riestra·T. Oosterbroek·E. Kuulkers·A. Orr·A. N. Parmar
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Abstract

On 2003 September 17 INTEGRAL discovered a bright transient source 3 degrees from the Galactic Center, IGR J17544-2619. The field containing the transient was observed by XMM-Newton on 2003 March 17 and September 11 and 17. A bright source, at a position consistent with the INTEGRAL location, was detected by the European Photon Imaging Camera (EPIC) during both September observations with mean 0.5-10 keV unabsorbed luminosities of 1.1x10^35 and 5.7x10^35 erg s-1 for an (assumed) distance of 8 kpc. The source was not detected in 2003 March, with a 0.5-10 keV luminosity of < 3.8x10^32 erg s-1. The September 11 and 17 EPIC spectra can be represented by a power-law model with photon indices of 2.25+/-0.15 and 1.42+/-0.17, respectively. Thus, the 0.5-10 keV spectrum hardens with increasing intensity. The low-energy absorption during both September observations is comparable to the interstellar value. The X-ray lightcurves for both September observations show energy dependent flaring which may be modeled by changes in either low-energy absorption or power-law index.

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R. Gonzalez-Riestra, T. Oosterbroek, E. Kuulkers, A. Orr, A. N. Parmar. 2004-02-12. XMM-Newton observations of the INTEGRAL X-ray transient J17544-2619. https://doi.org/10.1051/0004-6361%3A20035940

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