{
  "bibcode": "2015GCN.17548....1B",
  "body": "A. Belfiore (INAF/IASF Milano), A. Tiengo (IUSS Pavia), G. L. Israel \n(INAF/OA Roma), A. M. Read (U. Leicester), R. Salvaterra, D. Salvetti \n(INAF/IASF Milano), G. Novara (IUSS Pavia), S. Mereghetti, M. Marelli \n(INAF/IASF Milano), G. Rodriguez (INAF/OA Roma), G. Lisini (IUSS Pavia), \nS. R. Rosen (U. Leicester), A. De Luca�� (INAF/IASF Milano), report on \nbehalf of the EXTraS collaboration:\n\nBased on the preliminary results of the EXTraS project (DeLuca et al. \n2015, arXiv:1503.01497), we report on the analysis of XMM-Newton archival \ndata of 3XMM J004514.7+415035 (aka [PFH2005] 622, Pietsch et al. 2005, ApJ \n434, 483), the candidate X-ray counterpart of GRB 150301C�� (aka Swift \nJ0045.2+4151, GCN Circ 17512, 17516, 17536, 17544). The source is detected \nby the EPIC instrument at a 0.2-12 keV flux level of ~10^-14 erg/cm^2/s in \ntwo observations (2002-01-26 and 2007-01-05), while only upper limits of \n~5x10^-14 erg/cm^2/s can be set from 5 shorter observations performed in \nJuly 2006. Shallow upper limits of ~10^-12 erg/cm^2/s can be derived from \nthree non-detections during slew observations on 2005-07-03, 2007-01-06, \nand 2010-01-31.\n\nThe EPIC light curves of the two observations show no evidence for \nvariability. The search for coherent pulsations in the PN data, between \n0.15 and 10^4 s, gives negative results. The blind search for transients \ndoes not report any significant candidates within the BAT error circle of \nGRB 150301C in any of the seven XMM-Newton observations.\n\nWe extracted the EPIC spectra of 3XMM J004514.7+415035 and, after \nverifying that there are no significant spectral differences between the \ntwo observations, we fit them simultaneously with an absorbed power-law \nmodel. The best-fit parameters (errors at the 90% confidence level) are \nN_H<3x10^21 cm^-2 and photon index 1. 9 (-0.6, +0.8). Fixing the N_H to \nthe Galactic value of 10^21 cm^-2, as appropriate for sources in the M31 \ndisk, the photon index can be constrained in the 1.6-2.2 range (C-stat=142 \nfor 143 degrees of freedom) and the unabsorbed flux in the 0.1-10 keV \nrange is (1.3 +/- 0.3) x10^-14 erg/cm^2/s, corresponding to ~6x10^35 erg/s \nat the M31 distance.\n\nWe note that the properties of 3XMM J004514.7+41503 are consistent with \nthose of an active magnetar, like, e.g., SGR1806-20, at the distance of \nM31. Considering that the duration, fluence and spectrum of the burst \ndetected by BAT are compatible with an intermediate flare from a magnetar \nin M31, 3XMM J004514.7+41503 might be considered as a magnetar candidate \nin the Andromeda galaxy.\n\nPlots of the long term flux evolution, the background-subtracted and \nexposure-corrected light curves, and the power density spectra with pulsed \nfraction upper limits can be found on the EXTraS website: \nhttp://www.extras-fp7.eu/index.php/home/90-extras/news/158-gcn-atel-1\n\nEXTraS (\"Exploring the X-ray Transient and variable Sky\") is a project \naimed at the systematic exploitation of the XMM/EPIC database, to search \nfor, and characterize variability (both periodic and aperiodic), to search \nfor new transients and to provide a phenomenological classification of \nvariable sources. All EXTraS results, products and tools will be released \nto the community at the end of the project. EXTraS is carried out by a \ncollaboration including INAF (Italy), IUSS (Italy), CNR/IMATI (Italy), \nUniversity of Leicester (UK), MPE (Germany) and ECAP (Germany) and has \nbeen funded within the EU-FP7 framework (grant agreement n. 607452).",
  "circularId": 17548,
  "createdOn": 1425655731000,
  "email": "sandro@iasf-milano.inaf.it",
  "subject": "Swift J0045.2+4151: analysis of XMM-Newton archival data",
  "submitter": "Sandro Mereghetti at IASF/CNR  <sandro@iasf-milano.inaf.it>"
}