Magnetars as persistent hard X-ray sources: INTEGRAL discovery of a hard tail in SGR 1900+14
Abstract
Using 2.5 Ms of data obtained by the INTEGRAL satellite in 2003-2004, we discovered persistent hard X-ray emission from the soft gamma-ray repeater SGR 1900+14. Its 20-100 keV spectrum is well described by a steep power law with photon index Gamma=3.1+/-0.5 and flux 1.5E-11 erg/cmsq/s. Contrary to SGR 1806-20, the only other soft gamma-ray repeater for which persistent emission above 20 keV was reported, SGR 1900+14 has been detected in the hard X-ray range while it was in a quiescent state (the last bursts from this source were observed in 2002). By comparing the broad band spectra (1-100 keV) of all the magnetars detected by INTEGRAL (the two SGRs and three anomalous X-ray pulsars) we find evidence for a different spectral behaviour of these two classes of sources.
Cite
@article{arxiv.astro-ph/0602359,
title = {Magnetars as persistent hard X-ray sources: INTEGRAL discovery of a hard tail in SGR 1900+14},
author = {D. Gotz and S. Mereghetti and A. Tiengo and P. Esposito},
journal= {arXiv preprint arXiv:astro-ph/0602359},
year = {2009}
}
Comments
5 pages, 2 figures, submitted to A&A Letters