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Magnetars as persistent hard X-ray sources: INTEGRAL discovery of a hard tail in SGR 1900+14

D. Gotz·S. Mereghetti·A. Tiengo·P. Esposito
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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.

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D. Gotz, S. Mereghetti, A. Tiengo, P. Esposito. 2006-02-16. Magnetars as persistent hard X-ray sources: INTEGRAL discovery of a hard tail in SGR 1900+14. https://doi.org/10.1051/0004-6361%3A20064870

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