{
  "bibcode": "2020GCN.26895....1M",
  "body": "M. J. Moss (GWU), A. P. Beardmore (U Leicester),\nP. A. Evans (U Leicester), C. Gronwall (PSU), J.D. Gropp (PSU),\nJ. A. Kennea (PSU), N. J. Klingler (PSU), A. Y. Lien (GSFC/UMBC),\nF. E. Marshall (NASA/GSFC), K. L. Page (U Leicester),\nM. H. Siegel (PSU) and A. Tohuvavohu (U Toronto) report on behalf of\nthe Neil Gehrels Swift Observatory Team:\n\nAt 14:44:31 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 200127A (trigger=952791).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 295.204, +44.910 which is \n   RA(J2000) = 19h 40m 49s\n   Dec(J2000) = +44d 54' 35\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  As is usual with an image trigger, the available\nBAT light curve shows no significant structure. \n\nThe XRT began observing the field at 14:46:52.1 UT, 140.5 seconds after\nthe BAT trigger. Using promptly downlinked data we find a bright,\nfading, uncatalogued X-ray source located at RA, Dec 295.19447,\n44.90030 which is equivalent to:\n   RA(J2000)  = 19h 40m 46.67s\n   Dec(J2000) = +44d 54' 01.1\"\nwith an uncertainty of 3.5 arcseconds (radius, 90% containment). This\nlocation is 42 arcseconds from the BAT onboard position, within the BAT\nerror circle. This position may be improved as more data are received;\nthe latest position is 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 consistent with the Galactic value of 2.17\nx 10^21 cm^-2 (Willingale et al. 2013). \n\nThe initial flux in the 2.5 s image was 9.40e-10 erg cm^-2 s^-1 (0.2-10\nkeV). \n\nUVOT took a finding chart exposure of 250 seconds with the U filter starting\n309 seconds after the BAT trigger. No credible afterglow candidate has been\nfound in the initial data products. The 2.7'x2.7' sub-image covers 100% of the\nXRT error circle. The typical 3-sigma upper limit has been about 19.2 mag. The\n8'x8' region for the list of sources generated on-board covers 100% of the XRT\nerror circle. The list of sources is typically complete to about 18.0 mag. No\ncorrection has been made for the expected extinction corresponding to E(B-V) of\n0.16. \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": 26895,
  "createdOn": 1580137457000,
  "email": "caryl@swift.psu.edu",
  "subject": "GRB 200127A: Swift detection of a burst",
  "submitter": "Caryl Gronwall at PSU/Swift-UVOT  <caryl@swift.psu.edu>",
  "eventId": "GRB 200127A"
}