{
  "bibcode": "2017GCN.20883....1L",
  "body": "A. Y. Lien (GSFC/UMBC), S.D. Barthelmy (NASA/GSFC), D.M. Palmer (LANL),\nT. Sakamoto (AGU), A. A. Breeveld (MSSL-UCL), A.P. Beardmore (U. Leicester),\nD.N. Burrows (PSU), S. Campana (INAF-OAB), S.B. Cenko (NASA/GSFC),\nG. Cusumano (INAF-IASF PA), A. D'Ai (INAF-IASFPA), P. D'Avanzo (INAF-OAB),\nV.D'Elia(ASDC), P.A. Evans (U. Leicester), P. Giommi (ASI), C. Gronwall (PSU),\nJ. A. Kennea (PSU), H.A. Krimm (CRESST/GSFC/USRA), N.P.M. Kuin (UCL-MSSL),\nF.E. Marshall (NASA/GSFC), A. Melandri (INAF-OAB), B. Mingo (U. Leicester),\nJ.A. Nousek (PSU), S.R. Oates (Uni. of Warwick), P.T. O'Brien (U. Leicester),\nJ.P. Osborne (U. Leicester), C. Pagani (U. Leicester), K.L. Page (U.Leicester),\nM. Perri (ASDC), J.L. Racusin (NASA/GSFC), B. Sbarufatti (INAF-OAB/PSU),\nM.H. Siegel (PSU), G. Tagliaferri (INAF-OAB), E. Troja (NASA/GSFC/UMCP)\nreport on behalf of the Swift team:\n\nWe report the search results in the BAT data within T0 \u001b$B!^\u001b(B 100 s of the\nLIGO event G277583 (LIGO/VIRGO Collaboration GCN Circ. 20860),\nwhere T0 is the LIGO trigger time (2017-03-13T22:40:09.593 UTC).\n\nThe BAT pointing position at T0 is\nRA = 44.214 deg,\nDEC = -47.634 deg,\nROLL = 306.125 deg.\nThe BAT Field of View (>10% partial coding) covers 19.22% of the integrated\nLIGO localization probability.\n\nNo significant detections (signal-to-noise ratio > 4 sigma) are found\nin the BAT raw light curves with time bins of 64 ms, 1 s, and 1.6 s, respectively.\nAssuming an on-axis (100% coded) short GRB with a typical spectrum in the BAT\nenergy range (i.e., a simple power-law model with a power-law index of -1.32;\nLien & Sakamoto et al. 2016), the 4-sigma upper limit in the 1-s binned light\ncurve corresponds to a flux upper limit (15-350 keV) of ~ 6.7 x 10^-8 erg/s/cm^2.\nMoreover, no event data are found within T0 +/- 100 s.\n\nBAT retains decreased, but significant, sensitivity to rate increases for\ngamma-ray events outside of its FOV. About 59.52% of the integrated LIGO\nlocalization probability was outside of the BAT FOV but above the Earth's limb\nfrom Swift's location, and the corresponding flux upper limits for this region\nare within roughly an order of magnitude of those within the FOV.\n\nAll the BAT analyses use the LIGO sky map cWB_plus_LIB.fits.gz\n(LIGO/VIRGO Collaboration GCN Circ. 20860).",
  "circularId": 20883,
  "createdOn": 1489722551000,
  "email": "tsakamoto@phys.aoyama.ac.jp",
  "subject": "LIGO/Virgo G277583: Swift/BAT data search",
  "submitter": "Takanori Sakamoto at Aoyama Gakuin U  <tsakamoto@phys.aoyama.ac.jp>",
  "eventId": "LIGO/Virgo G277583"
}