GCN Circular 8165
Subject
SGR 0501+4516: preliminary results of the first XMM-Newton observation
Date
2008-09-02T13:51:00Z (16 years ago)
From
Nanda Rea at U of Amsterdam <nrea@science.uva.nl>
N. Rea (U. Amsterdam), S. Mereghetti (INAF-IASF, Milan), G.L Israel
(INAF-OAR), P. Esposito, A. Tiengo (INAF-IASF, Milan), S. Zane (UCL-MSSL)
report on behalf of a larger collaboration:
XMM-Newton observed the new Soft Gamma-ray Repeater SGR 0501+4516
(Holland et al., GCN 8112; Barthelmy et al., GCN 8113)
for ~49ks on 2008 August 23rd starting at 01:04:00 (UT).
Preliminary results show that the source flux is enhanced in
the soft X-ray range with respect to the possible quiescent
ROSAT counterpart (Kennea et al., Atel 1675).
The source persistent EPIC-PN spectrum is well fitted (in the 1-10keV
energy range; reduced chi2 = 1.02) by an absorbed blackbody plus a
power-law with Nh = 0.89(2) x 1022 cm-2, kT = 0.69(5) keV and photon
index Gamma= 2.76(6). The absorbed 1-10keV flux is 3.96x10-11
erg/s/cm2.
We measure a spin period of 5.762069(5)s (consistent with the
RXTE and Swift-XRT determinations: Gogus et al., Atel 1677; Mangano et
al., Atel 1682), with a fundamental component pulsed fraction of 40(1)%
(pulsed fraction defined as the background-corrected semi-amplitude of
the best fitting sine component, and in the whole EPIC-PN energy band).
Several short X-ray bursts have been detected in this observation,
the brightest ones also observed by Swift BAT (Palmer et al., Atel 1678).
A detailed analysis of this and the subsequent observations of our
XMM-Newton monitoring program (Rea et al., GCN 8152) is in progress.
Note that we postponed the last observation of our monitoring (September
6th, see GCN 8152), and will promptly diffuse a new date encouraging
multiwavelegth follow-ups.
We thank Norbert Schartel and the XMM-Newton team for carrying out this
ToO observation.
[GCN OPS NOTE(10sep08): Per author's request, in the Subject-line,
the "0105" was changed to "0501".]