{
  "bibcode": "2019GCN.23928....1B",
  "body": "S. D. Barthelmy (GSFC), A. Y. Lien (GSFC/UMBC) and\nK. L. Page (U Leicester) report on behalf of the Neil Gehrels Swift\nObservatory Team:\n\nAt 06:12:49 UT, the Swift Burst Alert Telescope (BAT) triggered and\nlocated MAXI J1631-479 (trigger=890732).  Swift slewed immediately to the source. \nThe BAT on-board calculated location is \nRA, Dec 247.821, -47.792 which is \n   RA(J2000) = 16h 31m 17s\n   Dec(J2000) = -47d 47' 30\"\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 06:21:16.4 UT, 507.0 seconds after\nthe BAT trigger. XRT found a bright X-ray source. However, the image was \ncontaminated by a cosmic ray, so the localisation was skewed, and no \naccurate position can be given. No event data are yet available to \ndetermine the column density using X-ray spectroscopy. \n\nThe initial flux in the 0.1 s image was 4.57e-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 515 seconds after the BAT trigger. No credible source has\nbeen found in the initial data products. The 2.7'x2.7' sub-image covers 100% of\nthe XRT error circle. Because of the density of catalogued stars, further\nanalysis is required to report an upper limit for any source in the\nsub-image. The 8'x8' region for the list of sources generated on-board covers\n100% of the XRT error circle. Because of the density of catalogued stars,\nfurther analysis is required to report an upper limit for any source in the\nregion. No correction has been made for the large, but uncertain, extinction\nexpected.",
  "circularId": 23928,
  "createdOn": 1551163126000,
  "email": "klp5@leicester.ac.uk",
  "subject": "Trigger 890732: Swift detection of MAXI J1631-479",
  "submitter": "Kim Page at U.of Leicester  <klp5@leicester.ac.uk>"
}