{
  "bibcode": "2019GCN.24017....1L",
  "body": "A. Y. Lien (GSFC/UMBC) and K. L. Page (U Leicester) report on behalf\nof the Neil Gehrels Swift Observatory Team:\n\nAt 09:00:17 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated GRO J2058+42 (trigger=895257).  Swift slewed immediately to the source. \nThe BAT on-board calculated location is \nRA, Dec 314.698, +41.822 which is \n   RA(J2000) = 20h 58m 47s\n   Dec(J2000) = +41d 49' 20\"\nwith an uncertainty of 3 arcmin (radius, 90% containment, including \nsystematic uncertainty).  As is usual with an image trigger, the available\nBAT light curve shows no significant structure. \n\nThe XRT began observing the field at 09:02:24.7 UT, 127.3 seconds after\nthe BAT trigger. XRT found a bright X-ray source located at RA, Dec\n314.6953, 41.7772 which is equivalent to:\n   RA(J2000)  = 20h 58m 46.87s\n   Dec(J2000) = +41d 46' 37.9\"\nwith an uncertainty of 5.9 arcseconds (radius, 90% containment). This\nlocation is 161 arcseconds from the BAT onboard position, within the\nBAT error circle. This position is 4.8 arcseconds from a known X-ray\nsource: 1SXPS J205847.2+414637. This source is in the Swift XRT 1SXPS\ncatalogue with a mean 0.3-10 keV count-rate of 1.350 +/- 0.043 ct/sec;\nsee http://www.swift.ac.uk/1SXPS/1SXPSJ205847.2%2B414637 for details of\nthese previous observations. 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 7.09e-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\n131 seconds after the BAT trigger. No credible afterglow candidate has been\nfound in the initial data products. The 2.7'x2.7' sub-image covers 100% of the\nXRT error circle. The typical 3-sigma upper limit has been about 19.2 mag. The\n8'x8' region for the list of sources generated on-board covers 100% of the XRT\nerror circle. The list of sources is typically complete to about 18.0 mag. No\ncorrection has been made for the large, but uncertain, extinction expected. \n\nSwift-BAT previously triggered on this source on 2019 March 22 (GCN Circ. 23985). \nThe BAT transient monitor of this source shows it to be in outburst:\nhttps://swift.gsfc.nasa.gov/results/transients/weak/GROJ2058p42/",
  "circularId": 24017,
  "createdOn": 1553678391000,
  "email": "klp5@leicester.ac.uk",
  "subject": "Swift Trigger 895257: Detection of GRO J2058+42 in outburst",
  "submitter": "Kim Page at U.of Leicester  <klp5@leicester.ac.uk>"
}