{
  "bibcode": "2021GCN.29844....1M",
  "body": "M. J. Moss (GWU), P. A. Evans (U Leicester), C. Gronwall (PSU),\nJ.D. Gropp (PSU), J. A. Kennea (PSU), K. L. Page (U Leicester) and\nB. Sbarufatti (PSU) report on behalf of the Neil Gehrels Swift\nObservatory Team:\n\nBAT triggered on GRB 210420B (trigger 1044382) at some time before 18:50\nUT. Due to telemetry gaps, we have only XRT data for this burst and\ntherefore at the present time cannot give a precise trigger time, or\ninformation about the BAT light curve. The most likely trigger time is\nbetween 18:20 and 18:50 UT. Once the full dataset has been downlinked we\nwill be able to derive a precise trigger time and analyse the BAT light\ncurve. \n\nUsing promptly downlinked data we find an uncatalogued X-ray source\nlocated at RA, Dec 254.32245, 42.56951 which is equivalent to:\n   RA(J2000)  = 16h 57m 17.39s\n   Dec(J2000) = +42d 34' 10.2\"\nwith an uncertainty of 3.6 arcseconds (radius, 90% containment). This\nposition may be improved as more data are received; the latest position\nis available at https://www.swift.ac.uk/sper. \n\nA power-law fit to a spectrum formed from promptly downlinked event\ndata gives a column density in excess of the Galactic value (2.09 x\n10^20 cm^-2, Willingale et al. 2013), with an excess column of 2.1\n(+1.75/-1.59) x 10^21 cm^-2 (90% confidence). \n\nBurst Advocate for this burst is M. J. Moss (mikejmoss3 AT gmail.com). \nPlease contact the BA by email if you require additional information\nregarding Swift followup of this burst. In extremely urgent cases, after\ntrying the Burst Advocate, you can contact the Swift PI by phone (see\nSwift TOO web site for information: http://www.swift.psu.edu/)",
  "circularId": 29844,
  "createdOn": 1618947295000,
  "email": "klp5@leicester.ac.uk",
  "subject": "GRB 210420B: Swift detection of a burst",
  "submitter": "Kim Page at U.of Leicester  <klp5@leicester.ac.uk>",
  "eventId": "GRB 210420B"
}