The FirstXMM‐NewtonObservations of the Soft Gamma‐Ray Repeater SGR 1900+14

A ~50 ks XMM-Newton observation of SGR 1900+14 has been carried out inSeptember 2005, after almost three years during which no bursts were detectedfrom this soft gamma-ray repeater. The 0.8-10 keV spectrum was well fit by apower law plus blackbody model with photon index 1.9+/-0.1, temperaturekT=0.47+/-0.02 keV and N_H = (2.12+/-0.08)x10^22 cm^-2, similar to previousobservations of this source. The flux was ~5x10^{-12} erg/cm2/s, a factor 2dimmer than the typical value and the smallest ever seen from SGR 1900+14. Thelong term fading of the persistent emission has been interrupted by the recentburst reactivation of the source. A target of opportunity XMM-Newtonobservation performed in April 2006 showed a flux ~15% higher. This variationwas not accompanied by significant changes in the spectrum, pulsed fraction andlight curve profile. We searched for emission and absorption lines in thespectra of the two observations, with negative results and setting tight upperlimits of 50-200 eV (3 sigma), depending on the assumed line energy and width,on the equivalent width of lines in the 1-9 keV range.Comment: accepted for publication on The Astrophysical Journa