{
  "bibcode": "2021GCN.30929....1B",
  "body": "M. G. Bernardini (INAF-OAB), P. D'Avanzo (INAF-OAB),\nN. J. Klingler (GSFC/UMBC/CRESSTII), A. Y. Lien (U Tampa),\nA. Melandri (INAF-OAB), K. L. Page (U Leicester), D. M. Palmer (LANL)\nand T. Sbarrato (INAF-OAB) report on behalf of the Neil Gehrels Swift\nObservatory Team:\n\nAt 10:42:36 UT, the Swift Burst Alert Telescope (BAT) triggered on \nan event with marginal significance (trigger=1078701). Swift slewed \nimmediately to the location. \nThe BAT on-board calculated location is \nRA, Dec 287.080, +29.822 which is \n   RA(J2000) = 19h 08m 19s\n   Dec(J2000) = +29d 49' 19\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve doesn't show anything\nsignificant. \n\nThe XRT began observing the field at 10:44:08.6 UT, 92.8 seconds after\nthe BAT trigger. No source was detected in 127 s of promptly downlinked\ndata. We are waiting for the full dataset to detect and localise the\nXRT counterpart. \n\nUVOT took a finding chart exposure of 138 seconds with the White filter\nstarting 97 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 25% of\nthe BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. \nThe 8'x8' region for the list of sources generated on-board covers 100% of the\nBAT error circle. The list of sources is typically complete to about 18 mag. No\ncorrection has been made for the expected extinction corresponding to E(B-V) of\n0.231. \n\nDue to the marginal detection significance in both BAT rates and\non-board  image (6.48 and 6.50 sigma respectively) with no detection\nin the ground  image analysis, and the lack of detection by XRT,  we\nbelieve that this is probably a noise fluctuation in BAT and  not an\nastrophysical event.",
  "circularId": 30929,
  "createdOn": 1633863639000,
  "email": "palmer@lanl.gov",
  "subject": "Swift Trigger 1078701 is probably not a GRB",
  "submitter": "David Palmer at LANL  <palmer@lanl.gov>"
}