{
  "createdOn": 1768301275895,
  "bibcode": "2026GCN.43387....1G",
  "body": "R. Gupta (NASA GSFC), A. Y. Lien (U Tampa), K. L. Page (U Leicester),\nD. M. Palmer (LANL), C. Salvaggio (INAF-OAB) and\nB. Sbarufatti (INAF-OAB) report on behalf of the Neil Gehrels Swift\nObservatory Team:\n\nAt 10:14:06 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated an event (trigger=1439093).  Swift slewed immediately to the location.\nThe BAT on-board calculated location is \nRA, Dec 357.372, +9.041 which is \n   RA(J2000) = 23h 49m 29s\n   Dec(J2000) = +09d 02' 29\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  We only have limited BAT light curve information \nat this moment, current light curve showed some potential pulse-like structure\nin the low energy band (15-25 keV), but nothing significant in other energy bands. \nTherefore, the pulse-like structure may be due to noisy detectors. \nFurther ground analysis is required to determine the nature of this trigger.\n\nThe XRT began observing the field at 10:16:22.6 UT, 136.1 seconds after\nthe BAT trigger. No source was detected in 1.5 ks of promptly\ndownlinked data.\n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 139 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\n0.098.\n\nDue to the marginal detection of this event in the BAT Image (6.5 sigma)\nand the lack of the an XRT counterpart detection, we believe that\nthis trigger is most likely to be a statistical fluctuation in the\ninstrument and not a true astrophysical event. Determination of the reality\nof this event will require the full downlinked dataset. We retain the\nname GRB 260113A for this event to avoid confusion.\n\nBurst Advocate for this burst is R. Gupta (rahulbhu.c157 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/)\n\n",
  "eventId": "GRB 260113A",
  "submittedHow": "email",
  "circularId": 43387,
  "submitter": "K.L. Page at U Leicester <klp5@leicester.ac.uk>",
  "subject": "Swift Trigger 1439093: is probably not GRB 260113A"
}