A XMM-Newton View of the Soft Gamma-ray Repeater SGR 1806-20: Long Term Variability in the pre-Giant Flare Epoch

Mereghetti, S.
Tiengo, A.
Esposito, P.
Goetz, D.
Stella, L.
Israel, G. L.
Rea, N.
Feroci, M.
Turolla, Roberto
Zane, S.

Publication date

January 2005

Abstract

The low-energy (<10 keV) X-ray emission of the soft gamma repeater SGR 1806-20 has been studied by means of four XMM-Newton observations carried out in the last two years, the latest performed in response to a strong sequence of hard X-ray bursts observed on 2004 October 5. The source was caught in different states of activity; over the 2003-2004 period, the 2-10 keV flux doubled with respect to the historical level observed previously. The long-term rise in luminosity was accompanied by a gradual hardening of the spectrum, with the power-law photon index decreasing from 2.2 to 1.5, and by a growth of the bursting activity. The pulse period measurements obtained in the four observations are consistent with an average spin-down rate of 5.5 7...

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A XMM-Newton View of the Soft Gamma-ray Repeater SGR 1806-20: Long Term Variability in the pre-Giant Flare Epoch

Abstract

Extracted data

A XMM-Newton View of the Soft Gamma-ray Repeater SGR 1806-20: Long Term Variability in the pre-Giant Flare Epoch

Abstract

Extracted data

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