{
  "bibcode": "2021GCN.30447....1S",
  "body": "B. Sbarufatti (PSU), H. A. Krimm (NSF) and K. L. Page (U Leicester)\nreport on behalf of the Neil Gehrels Swift Observatory Team:\n\nAt 09:43:11 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 210712A (trigger=1059881).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 97.337, -35.393 which is \n   RA(J2000) = 06h 29m 21s\n   Dec(J2000) = -35d 23' 33\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve showed a single-peaked\nstructure with a duration of about 20 sec, followed by lower-level \nextended emission.  The peak count rate was ~2600 counts/sec (15-350 keV), \nat ~0 sec after the trigger. \n\nThe XRT began observing the field at 09:44:32.5 UT, 80.6 seconds after\nthe BAT trigger. Using promptly downlinked data we find a bright,\nuncatalogued X-ray source with an enhanced position: RA, Dec 97.3319,\n-35.3717 which is equivalent to:\n   RA(J2000)  = 06h 29m 19.66s\n   Dec(J2000) = -35d 22' 18.0\"\nwith an uncertainty of 1.9 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.  We cannot determine\nwhether the source is fading at the present time. \n\nA power-law fit to a spectrum formed from promptly downlinked event\ndata gives a column density in excess of the Galactic value (8.88 x\n10^20 cm^-2, Willingale et al. 2013), with an excess column of 6.5\n(+5.28/-4.30) x 10^21 cm^-2 (90% confidence). \n\nThe initial flux in the 2.5 s image was 3.52e-09 erg cm^-2 s^-1 (0.2-10\nkeV). \n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 90 seconds after the BAT trigger. No credible afterglow candidate has\nbeen found in the initial data products. The 2.7'x2.7' sub-image covers none of\nthe XRT error circle. The 8'x8' region for the list of sources generated\non-board covers 100% of the XRT error circle. The list of sources is typically\ncomplete to about 18 mag. No correction has been made for the expected\nextinction corresponding to E(B-V) of 0.076. \n\nBurst Advocate for this burst is B. Sbarufatti (bxs60 AT psu.edu). \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": 30447,
  "createdOn": 1626083901000,
  "email": "hkrimm@nsf.gov",
  "subject": "GRB 210712A: Swift detection of a burst",
  "submitter": "Hans Krimm at NSF/NASA-GSFC  <hkrimm@nsf.gov>",
  "eventId": "GRB 210712A"
}