{
  "subject": "GRB 150724B: Swift-XRT afterglow detection",
  "eventId": "GRB 150724B",
  "bibcode": "2015GCN.18101....1O",
  "createdOn": 1438405500000,
  "circularId": 18101,
  "submitter": "Kim Page at U.of Leicester  <kpa@star.le.ac.uk>",
  "email": "kpa@star.le.ac.uk",
  "body": "J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), C. Pagani (U.\nLeicester), V. D'Elia (ASDC), A. D'ai (INAF-IASFPA), A. Maselli \n(INAF-IASFPA), L.M. McCauley (PSU), J.A. Kennea (PSU), B. Sbarufatti\n(INAF-OAB/PSU) and P.A. Evans (U. Leicester) report on behalf of the\nSwift-XRT team:\n\nSwift-XRT has conducted further observations of the field of the\nFermi/LAT-detected burst GRB 150724B (Bissaldi et al. GCN Circ. 18065).\nThe observations now extend from T0+88.6 ks to T0+607.8 ks. The source\npreviously reported by Osborne et al. (GCN Circ. 18069), \"Source 1\", is\nfading with 3-sigma significance, and is therefore likely the GRB\nafterglow.  The position of this source is RA, Dec=351.8905, +3.8181\nwhich is equivalent to:\n\nRA (J2000): 23:27:33.71\nDec(J2000): +03:49:05.2\n\nwith an uncertainty of 4.1 arcsec (radius, 90% confidence).  This\nposition is 9.1 arcmin from the Fermi/LAT position.  The source is\nfading with alpha >0.3.\n\nThe results of the XRT-team automatic analysis of the likely afterglow\nare at http://www.swift.ac.uk/ToO_GRBs/00020543/index_1.php.\nThe results of the full analysis of the XRT observations are available\nat http://www.swift.ac.uk/ToO_GRBs/00020543.\n\nThis circular is an official product of the Swift-XRT team."
}