{
  "createdOn": 1683722691364,
  "eventId": "GRB 230510A",
  "submitter": "K.L. Page at U Leicester <klp5@leicester.ac.uk>",
  "body": "\nR. A. J. Eyles-Ferris (U Leicester), P. A. Evans (U Leicester),\nJ.D. Gropp (PSU), J. A. Kennea (PSU), F. E. Marshall (NASA/GSFC),\nK. L. Page (U Leicester), P. Romano (INAF-OAB), T. Sakamoto (AGU),\nB. Sbarufatti (INAF-OAB) and M. A. Williams (PSU) report on behalf of\nthe Neil Gehrels Swift Observatory Team:\n\nAt 12:06:28 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 230510A (trigger=1167973).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 318.156, +34.443 which is \n   RA(J2000) = 21h 12m 37s\n   Dec(J2000) = +34d 26' 33\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve showed a complex \nstructure with a duration of about 60 sec.  The peak count rate\nwas ~5100 counts/sec (15-350 keV), at ~13 sec after the trigger. \n\nThe XRT began observing the field at 12:07:31.9 UT, 63.4 seconds after\nthe BAT trigger. XRT found a bright, uncatalogued X-ray source located\nat RA, Dec 318.1314, 34.4424 which is equivalent to:\n   RA(J2000)  = 21h 12m 31.54s\n   Dec(J2000) = +34d 26' 32.6\"\nwith an uncertainty of 6.5 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\nThe initial flux in the 0.1 s image was 1.19e-08 erg cm^-2 s^-1 (0.2-10\nkeV). \n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 72 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 100% of\nthe XRT 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\nXRT 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\n0.144. \n\nThis trigger was initially marked as matching a source in the BAT\nground catalogue: IGR J21117+3427, a known gamma-ray source. However,\nthe XRT localisation is more than 9 arcmin from the known position of\nIGR J21117+3427, outside its error region of 3.5 arcmin (ATel 873). \nThis, together with the BAT transient monitor light-curve showing\nlittle sign of variation suggests that this is in fact a new GRB. \n\nBurst Advocate for this burst is R. A. J. Eyles-Ferris (raje1 AT leicester.ac.uk). \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",
  "subject": "GRB 230510A: Swift detection of a burst",
  "bibcode": "2023GCN.33752....1E",
  "circularId": 33752
}