{
  "body": "S. Dichiara (PSU), J. J. DeLaunay (PSU), R. Gupta (NASA GSFC) and\nT. Sakamoto (AGU) report on behalf of the Neil Gehrels Swift\nObservatory Team:\n\nAt 22:25:19.59 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 250615A (trigger=1324646). Swift slewed immediately to the burst.\nThe BAT on-board calculated location is RA, Dec 290.344, +4.672 which is \n   RA(J2000) = 19h 21m 23s\n   Dec(J2000) = +04d 40’ 21\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve showed a complex structure \nwith a duration of about 55 sec.  The peak count rate \nwas ~5000 counts/sec (15-350 keV), at ~1 sec after the trigger.\n\nThe XRT began observing the field at 22:26:46.4 UT, 86.9 seconds after\nthe BAT trigger. Using promptly downlinked data we find a bright,\nfading, uncatalogued X-ray source located at RA, Dec 290.38466, 4.68467\nwhich is equivalent to:\n   RA(J2000)  = 19h 21m 32.32s\n   Dec(J2000) = +04d 41' 04.8\"\nwith an uncertainty of 3.6 arcseconds (radius, 90% containment). This\nlocation is 152 arcseconds from the BAT onboard position, within the\nBAT error circle. This position may be improved as more data are\nreceived; the latest position is available at\nhttps://www.swift.ac.uk/sper. \n\nA power-law fit to a spectrum formed from promptly downlinked event\ndata does not constrain the column density. \n\nThe initial flux in the 2.5 s image was 9.89e-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\n152 seconds after the BAT trigger. No credible afterglow candidate has been\nfound in the initial data products. Results from the 2.7'x2.7' sub-image are\nnot available at this time. 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 18.0 mag. No correction has been made for the large, but\nuncertain, extinction expected.\n\nBurst Advocate for this burst is S. Dichiara (sbd5667 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/)\n\n",
  "createdOn": 1750027464011,
  "bibcode": "2025GCN.40736....1D",
  "eventId": "GRB 250615A",
  "submitter": "Simone Dichiara at Pennsylvania State University <sbd5667@psu.edu>",
  "circularId": 40736,
  "subject": "GRB 250615A: Swift detection of a burst",
  "submittedHow": "email"
}