{
  "body": "K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), M. Perri (SSDC\n& INAF-OAR), V. D'Elia (SSDC & INAF-OAR), B. Sbarufatti (INAF-OAB), S.\nDichiara (PSU), J.A. Kennea (PSU), D.N. Burrows (PSU) and P.A. Evans\n(U. Leicester) reports on behalf of the Swift-XRT team:\n\nWe have analysed 1.7 ks of XRT data for the Einstein Probe/WXT-detected\nburst GRB 250215A, from 9.5 ks to 16.1 ks after the  Einstein Probe/WXT\ntrigger, also detected by Fermi/GBM (GCN Circ. 39327) and INTEGRAL (GCN\nCirc. 39331). The data are entirely in Photon Counting (PC) mode. \n\nWe detect a bright, previously uncatalogued X-ray source at the\nfollowing coordinates: RA/Dec(J2000) = 156.33119, -27.69834, which is\nequivalent to \n\nRA (J2000): 10 25 19.48\nDec(J2000): -27 41 54.0\n\nwith an uncertainty of 3.6 arcsec (radius, 90% confidence). This source\nis 6 arcsec from the FXT position (GCN Circ. 39329) and 0.35 arcsec\nfrom the NOT optical counterpart (GCN Circ. 39330).\n\nThe light curve can be modelled with a power-law decay with a decay\nindex of alpha=1.1 (+/-0.4).\n\nA spectrum formed from the PC mode data can be fitted with an absorbed\npower-law with a photon spectral index of 1.95 (+0.23, -0.22). The\nbest-fitting absorption column is  1.2 (+0.7, -0.5) x 10^21 cm^-2,\nconsistent with the Galactic value of 6.8 x 10^20 cm^-2 (Willingale et\nal. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux\nconversion factor deduced from this spectrum  is 3.5 x 10^-11 (4.4 x\n10^-11) erg cm^-2 count^-1. \n\nA summary of the PC-mode spectrum is thus:\nTotal column:\t     1.2 (+0.7, -0.5) x 10^21 cm^-2\nGalactic foreground: 6.8 x 10^20 cm^-2\nExcess significance: <1.6 sigma\nPhoton index:\t     1.95 (+0.23, -0.22)\n\nIf the light curve continues to decay with a power-law decay index of\n1.1, the count rate at T+24 hours will be 0.038 count s^-1,\ncorresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.3 x\n10^-12 (1.7 x 10^-12) erg cm^-2 s^-1.\n\nThe results of the XRT-team automatic analysis are available at\nhttp://www.swift.ac.uk/xrt_products/00019554.\n\nThis circular is an official product of the Swift-XRT team.\n\n",
  "submittedHow": "email",
  "bibcode": "2025GCN.39336....1P",
  "eventId": "GRB 250215A",
  "subject": "GRB 250215A: Swift-XRT refined Analysis",
  "circularId": 39336,
  "createdOn": 1739619554529,
  "submitter": "Phil Evans at U of Leicester <pae9@star.le.ac.uk>"
}