Broadband Observations of the New X-Ray Burster SAX J1747.0−2853 during the 1998 March Outburst

We report on our discovery and follow-up observations of the X-ray source SAXJ1747.0-2853 detected in outburst on 1998, March 10 with the BeppoSAX WideField Cameras in the energy range 2-28 keV. The source is located about halfdegree off the Galactic Nucleus. A total of 14 type-I X-ray bursts weredetected in Spring 1998, thus identifying the object as a likely low-mass X-raybinary harboring a weakly magnetized neutron star. Evidence for photosphericradius expansion is present in at least one of the observed bursts, leading toan estimate of the source distance of about 9 kpc. We performed a follow-uptarget of opportunity observation with the BeppoSAX Narrow Field Instruments onMarch 23 for a total elapsed time of 72 ks. The source persistent luminositywas 2.6x10^36 erg/s in the 2-10 keV energy range. The wide band spectral data(1-200 keV) are consistent with a remarkable hard X-ray spectrum detected up to150 keV, highly absorbed at low energies (Nh of the order of 10^23 cm^-2) andwith clear evidence for an absorption edge near 7 keV. A soft thermal componentis also observed, which can be described by single temperature blackbodyemission at about 0.6 keV.Comment: 11 pages, 3 figures, accepted for publication in ApJ Letter