{
  "bibcode": "2019GCN.25702....1B",
  "body": "S. D. Barthelmy (GSFC), F. E. Marshall (NASA/GSFC),\nB. Sbarufatti (PSU) and A. Tohuvavohu (Toronto) report on behalf of\nthe Neil Gehrels Swift Observatory Team:\n\nAt 07:02:29 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated MAXI J1807+132 (trigger=924641).  Swift slewed immediately to the source. \nThe BAT on-board calculated location is \nRA, Dec 272.070, +13.258 which is \n   RA(J2000)  =  18h 08m 17s\n   Dec(J2000) = +13d 15' 27\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  The BAT light curve shows several overlapping peaks\nwith a total duration of about 30 sec.  The peak count rate\nwas ~700 counts/sec (15-350 keV), at ~3 sec after the trigger. \n\nThe XRT began observing the field at 07:04:04.1 UT, 94.7 seconds after\nthe BAT trigger. XRT found a bright X-ray source located\nat RA, Dec 272.0331, 13.2514 which is equivalent to:\n   RA(J2000)  = 18h 08m 7.94s\n   Dec(J2000) = +13d 15' 05.0\"\nwith an uncertainty of 5.5 arcseconds (radius, 90% containment). This\nlocation is 131 arcseconds from the BAT onboard position, within the\nBAT error circle, and 5.5 arcseconds from the known position of MAXI J1807+132 \n(Kennea et al., ATel #10215). No event data are yet available to \ndetermine the column density using X-ray spectroscopy. \n\nThe initial flux in the 2.5 s image was 1.11e-09 erg cm^-2 s^-1 (0.2-10\nkeV). \n\nUVOT took a finding chart exposure of 150 seconds with the White filter\nstarting 105 seconds after the BAT trigger. There is a bright source in\nthe rapidly available 2.7'x2.7' sub-image at\n  RA(J2000)  =\t18:08:07.54 = 272.03143\n  DEC(J2000) = +13:15:05.7  =  13.25159\nwith a 90%-confidence error radius of about 0.61 arc sec. This position is 5.9\narc sec. from the center of the XRT error circle. The estimated magnitude is\n16.17 with a 1-sigma error of about  0.14. No correction has been made for the\nexpected extinction corresponding to E(B-V) of 0.15.",
  "circularId": 25702,
  "createdOn": 1568100907000,
  "email": "scott@milkyway.gsfc.nasa.gov",
  "subject": "Swift Trigger 924641 is an outburst from MAXI J1807+132",
  "submitter": "Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>"
}