{
  "bibcode": "2020GCN.27676....1P",
  "body": "M. Perri (ASDC), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), D.N. Burrows\n(PSU), J. D. Gropp (PSU), J.A. Kennea (PSU), J.P. Osborne (U.\nLeicester), K.L. Page (U. Leicester) and P.A. Evans (U. Leicester)\nreport on behalf of the Swift-XRT team:\n\nSwift-XRT has conducted further observations of the field of the\nINTEGRAL-detected burst GRB 200424A (Mereghetti et al. GCN Circ.\n27634). The observations now extend from T0+17.1 ks to T0+633.1 ks. \n\nOf the sources reported by Perri et al. (GCN Circ. 27640), \"Source 1\"\nis fading with 3-sigma significance, and is therefore likely the GRB\nafterglow. Using 1970 s of PC mode data and 1 UVOT image, we find an\nenhanced XRT position (using the XRT-UVOT alignment and matching UVOT\nfield sources to the USNO-B1 catalogue): RA, Dec = 307.50547, -39.70013\nwhich is equivalent to:\n\nRA (J2000): 20h 30m 01.31s\nDec(J2000): -39d 42' 00.5\"\n\nwith an uncertainty of 3.0 arcsec (radius, 90% confidence). This\nposition is 22 arcsec from the INTEGRAL position.  The source is fading\nwith alpha >0.3.\n\nThe results of the XRT-team automatic analysis of the likely afterglow\nare at https://www.swift.ac.uk/ToO_GRBs/00020989/Source1.php.\nThe results of the full analysis of the XRT observations are available\nat https://www.swift.ac.uk/ToO_GRBs/00020989.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 27676,
  "createdOn": 1588409284000,
  "email": "paolo.davanzo@inaf.it",
  "subject": "GRB 200424A: Swift-XRT afterglow detection",
  "submitter": "Paolo D'Avanzo at INAF - OAB  <paolo.davanzo@inaf.it>",
  "eventId": "GRB 200424A"
}