{
  "bibcode": "2015GCN.17510....1L",
  "body": "A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC), D. N. Burrows (PSU),\nJ. R. Cummings (NASA/UMBC), M. De Pasquale (INAF-IASFPA),\nL. M. Z. Hagen (PSU), J. A. Kennea (PSU), C. B. Markwardt (NASA/GSFC),\nA. Maselli (INAF-IASFPA), D. M. Palmer (LANL) and M. H. Siegel (PSU)\nreport on behalf of the Swift Team:\n\nAt 01:04:28 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated a source which could be a short GRB or a new SGR (trigger=632995). \nSwift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 244.286, -48.697, which is \n   RA(J2000)  =  16h 17m 09s\n   Dec(J2000) = -48d 41' 48\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve shows a single peak\nstructure with a duration of about 0.1 sec.  The peak count rate\nwas ~8500 counts/sec (15-350 keV), at ~0 sec after the trigger. \n\nThe XRT began observing the field at 01:05:26.6 UT, 58.3 seconds after\nthe BAT trigger. XRT found a bright, uncatalogued X-ray source located\nat RA, Dec 244.3047, -48.7131 which is equivalent to:\n   RA(J2000)  = +16h 17m 13.13s\n   Dec(J2000) = -48d 42' 47.2\"\nwith an uncertainty of 5.0 arcseconds (radius, 90% containment). This\nlocation is 73 arcseconds from the BAT onboard position, within the BAT\nerror circle. No event data are yet available to determine the column\ndensity using X-ray spectroscopy. \n\nUVOT took a finding chart exposure of 113 seconds with the White filter\nstarting 65 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 coverage of the XRT error circle by the 8'x8' region\nfor the list of sources generated on-board is uncertain because the large\nnumber of sources filled the available telemetry. The list of sources is\ntypically complete to about 18 mag. No correction has been made for the large,\nbut uncertain extinction expected. \n\nWe note that this source is near the Galactic Plane and Bulge \n(lat = 1.36, lon = 334) and so this might be a previously-unknown\nSoft Gamma Repeater. The burst has significant emission above 100 keV,\nwhich is unusual, but not unprecedented, for an SGR.  Further analysis\nof the full data set and continued observation is required to\ndetermine the nature of this source. \n\nBurst Advocate for this burst is A. Y. Lien (amy.y.lien AT nasa.gov). \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/too.html.)",
  "circularId": 17510,
  "createdOn": 1425173176000,
  "email": "scott@milkyway.gsfc.nasa.gov",
  "subject": "GRB 150301A: Swift detection of a short burst or new SGR",
  "submitter": "Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>",
  "eventId": "GRB 150301A"
}