{
  "bibcode": "2020GCN.28115....1D",
  "body": "A. D'Ai (INAF-IASFPA), D.N. Burrows (PSU), J. D. Gropp (PSU), J.A.\nKennea (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.\nMelandri (INAF-OAB), T. Sbarrato (INAF-OAB) and P.A. Evans (U.\nLeicester) report on behalf of the Swift-XRT team:\n\nSwift-XRT has performed follow-up observations of the INTEGRAL-detected\nburst GRB 200715A (Mereghetti et al. GCN Circ. 28110), collecting 3.3\nks of Photon Counting (PC) mode data between T0+7.5 ks and T0+26.2 ks. \n\n\nAn uncatalogued X-ray source is detected consistent with being within\n266 arcsec of the INTEGRAL position and is above the RASS limit, and is\ntherefore likely the GRB afterglow.  The position of this source is RA,\nDec=248.5377, -51.8356 which is equivalent to:\n\nRA (J2000): 16:34:9.04\nDec(J2000): -51:50:08.0\n\nwith an uncertainty of 3.7 arcsec (radius, 90% confidence).  This\nposition is 13 arcsec from the INTEGRAL position (Mereghetti et al. GCN\nCirc. 28110). \n\nThe light curve can be modelled with a power-law decay with a decay\nindex of alpha=1.06 (+0.32, -0.27).\n\nA spectrum formed from the PC mode data can be fitted with an absorbed\npower-law with a photon spectral index of 2.1 (+/-0.5). The\nbest-fitting absorption column is  1.06 (+0.60, -0.29) x 10^22 cm^-2,\nconsistent with the Galactic value of 7.6 x 10^21 cm^-2 (Willingale et\nal. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux\nconversion factor deduced from this spectrum  is 4.8 x 10^-11 (9.4 x\n10^-11) erg cm^-2 count^-1. \n\nA summary of the PC-mode spectrum is thus:\nTotal column:\t     1.06 (+0.60, -0.29) x 10^22 cm^-2\nGalactic foreground: 7.6 x 10^21 cm^-2\nExcess significance: <1.6 sigma\nPhoton index:\t     2.1 (+/-0.5)\n\nIf the light curve continues to decay with a power-law decay index of\n1.06, the count rate at T+24 hours will be 6.2 x 10^-3 count s^-1,\ncorresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.0 x\n10^-13 (5.8 x 10^-13) erg cm^-2 s^-1.\n\nThe results of the XRT-team automatic analysis are available at\nhttp://www.swift.ac.uk/xrt_products/00021018.\nThe results of the full analysis of the XRT observations are available\nat https://www.swift.ac.uk/ToO_GRBs/00021018.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 28115,
  "createdOn": 1594889071000,
  "email": "klp5@leicester.ac.uk",
  "subject": "GRB 200715A: Swift-XRT afterglow detection",
  "submitter": "Kim Page at U.of Leicester  <klp5@leicester.ac.uk>",
  "eventId": "GRB 200715A"
}