{
  "subject": "GRB 190829A: Swift detection of a burst consistent with a galaxy at z=0.08",
  "eventId": "GRB 190829A",
  "bibcode": "2019GCN.25552....1D",
  "createdOn": 1567110337000,
  "circularId": 25552,
  "submitter": "David Palmer at LANL  <palmer@lanl.gov>",
  "email": "palmer@lanl.gov",
  "body": "S. Dichiara (NASA/GSFC/UMCP), M. G. Bernardini (INAF-OAB),\nD. N. Burrows (PSU), P. D'Avanzo (INAF-OAB), C. Gronwall (PSU),\nJ.D. Gropp (PSU), J. A. Kennea (PSU), N. J. Klingler (PSU),\nH. A. Krimm (NSF), N. P. M. Kuin (UCL-MSSL), S. J. LaPorte (PSU),\nA. Melandri (INAF-OAB), K. L. Page (U Leicester), D. M. Palmer (LANL),\nM. H. Siegel (PSU), K. K. Simpson (PSU) and A. Tohuvavohu (Toronto)\nreport on behalf of the Neil Gehrels Swift Observatory Team:\n\nAt 19:56:44.60 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRB 190829A (trigger=922968).  Swift slewed immediately to the burst. \nThe BAT on-board calculated location is \nRA, Dec 44.540, -8.968 which is \n  RA(J2000) = 02h 58m 10s\n  Dec(J2000) = -08d 58' 03\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve showed a smaller peak\nat ~T-50 seconds followed by the main peak around T~0 with a \nduration of about 15 sec.  The peak count rate\nwas ~1500 counts/sec (15-350 keV), at ~0 sec after the trigger. \n\nThe XRT began observing the field at 19:58:21.9 UT, 97.3 seconds after\nthe BAT trigger. Using promptly downlinked data we find a bright,\nuncatalogued X-ray source with an enhanced position: RA, Dec 44.5440,\n-8.9579 which is equivalent to:\n   RA(J2000)  = 02h 58m 10.57s\n   Dec(J2000) = -08d 57' 28.6\"\nwith an uncertainty of 2.0 arcseconds (radius, 90% containment). This\nlocation is 39 arcseconds from the BAT onboard position, within the BAT\nerror circle. This position may be improved as more data are received;\nthe latest position is available at http://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 7.75e-10 erg cm^-2 s^-1 (0.2-10\nkeV). \n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 106 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\n0.05. \n\nThis GRB was also reported by the Fermi GBM Team (GCN #25551), \nat the time of the first peak. \n\nWe note the presence of a galaxy SDSS J025810.28-085719.2 with z=0.07914 \ncentered at a distance of 10 arcseconds from the XRT location. \nhttp://skyserver.sdss.org/dr14/en/tools/explore/Summary.aspx?id=1237652899156721762\n\nBurst Advocate for this burst is S. Dichiara (dichiara AT umd.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/)"
}