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ATEL # 1559; A. Tiengo (INAF-IASF Milano), N. Rea, M. Klein-Wolt, R. Wijnands (University of Amsterdam), G.L. Israel (INAF-OA Roma), P. Esposito (INAF-IASF Milano), S. Zane (UCL/MSSL), R. Starling (University of Leicester), S. Mereghetti, A. De Luca (INAF-IASF Milano), D. Gotz (CEA-Saclay)
on 5 Jun 2008; 9:58 UT
Password Certification: Andrea Tiengo (firstname.lastname@example.org)
Subjects: X-ray, Soft Gamma-ray Repeaters
Following the Swift detection of the reactivation of SGR 1627-41 (Palmer et al., GCN #7777; Woods et al., ATEL #1549; Golenetskii et al., GCN #7778), we searched for serendipitous pre-bursts X-ray observations of the region. Chandra observed the field of this SGR on 2008-05-27 UT 12:57:00 (Obs-ID 9007), ∼20 hours before the first burst detected by BAT from SGR 1627-41. The Chandra observation was performed using HRC-I with an exposure time of ∼1.2 ks, and the SGR position was at ∼15' from the aimpoint of the observation.
SGR 1627-41 was not detected in this pre-bursts Chandra observation. Taking into account the off-axis position of the source and PSF blurring, and assuming an absorbed power-law spectrum (NH=9×1022 cm-2 and Gamma=3.2; Mereghetti et al. 2006, A&A 450, 759), we infer a 3 sigma upper limit on the absorbed flux of 5×10-12 ergs cm-2 s-1 (0.5-10 keV band). This limit is significantly lower than the X-ray persistent flux measured 24 hours later during the first observation with Swift/XRT.