The First XMM‐Newton Observations of the Soft Gamma‐Ray Repeater SGR 1900+14

Abstract

A ∼50 ks XMM-Newton observation of SGR 1900+14 has been carried out in 2005 September, after almost 3 yr during which no bursts were detected from this soft gamma-ray repeater. The 0.8-10 keV spectrum was well fit by a power law plus blackbody model with photon index F = 1.9 ± 0.1, temperature kT = 0.47 ± 0.02 keV, and NH = (2.12 ± 0.08) × 10 22 cm-2, similar to previous observations of this source. The flux was ∼5 × 10-12ergs cm-2 s -1,a factor 2 dimmer than the typical value and the smallest ever seen from SGR 1900+14. The long-term fading of the persistent emission has been interrupted by the recent burst reactivation of the source. A Target of Opportunity XMM-Newton observation performed in 2006 April showed a flux ∼15% higher. This variation was not accompanied by significant changes in the spectrum, pulsed fraction, and light-curve profile. We searched for emission and absorption lines in the spectra of the two observations, with negative results and setting tight upper limits of 50-200 eV (3 σ), depending on the assumed line energy and width, on the equivalent width of lines in the 1-9 keV range. © 2006. The American Astronomical Society, All rights reserved.