{
  "bibcode": "2019GCN.24158....1P",
  "body": "D. M. Palmer (LANL), S. D. Barthelmy (NASA/GSFC),\nA. Y. Lien (GSFC/UMBC), T. Sakamoto (AGU),\nA. A. Breeveld (MSSL-UCL), A. P. Beardmore (U. Leicester),\nD. N. Burrows (PSU), S. Campana (INAF-OAB),\nS. B. Cenko (NASA/GSFC),G. Cusumano (INAF-IASF PA),\nA. D'Ai (INAF-IASFPA), P. D'Avanzo (INAF-OAB), V. D'Elia(ASDC),\nS. Emery (UCL-MSSL), P. A. Evans (U. Leicester), P. Giommi (ASI),\nC. Gronwall (PSU), D. Hartmann (Clemson U.), J. A. Kennea (PSU),\nH. A. Krimm (NSF), N. P. M. Kuin (UCL-MSSL), F. E. Marshall (NASA/GSFC),\nA. Melandri (INAF-OAB), B. Mingo (U. Leicester), J. A. Nousek (PSU),\nS. R. Oates (Uni. of Warwick), P. T. O'Brien (U. Leicester),\nJ. P. Osborne (U. Leicester), C. Pagani (U. Leicester),\nK. L. Page (U.Leicester), M. Perri (ASDC), J. L. Racusin (NASA/GSFC),\nB. Sbarufatti (INAF-OAB/PSU), M. H. Siegel (PSU),\nG. Tagliaferri (INAF-OAB), A. Tohuvavohu (PSU), E. Troja (NASA/GSFC/UMCP)\nreport on behalf of the Swift team:\n\nWe report the search results in the BAT data within T0 +/- 100 s of the\nLVC event S190421ar (LIGO/VIRGO Collaboration GCN Circ. 24141),\nwhere T0 is the LVC trigger time (2019-04-21T21:38:56 UTC).\n\nThe center of the BAT FOV at T0 is\nRA = 183.218 deg,\nDEC = 6.982 deg,\nROLL = 313.598 deg.\nThe BAT Field of View (>10% partial coding) covers 23.09% of the integrated\nLVC localization probability.\n\nWithin T0 +/- 100 s, no significant detections (signal-to-noise ratio\n>~ 5 sigma) are found in the BAT raw light curves with time bins of\n64 ms, 1 s, and 1.6 s, respectively. Assuming an on-axis (100% coded)\nshort GRB with a typical spectrum in the BAT energy range\n(i.e., a simple power-law model with a power-law index of -1.32,\nLien & Sakamoto et al. 2016), the 5-sigma upper limit in the 1-s binned\nlight curve corresponds to a flux upper limit (15-350 keV)\nof ~ 8.46 x 10^-8 erg/s/cm^2.\n\nBAT retains decreased, but significant, sensitivity to rate increases for\ngamma-ray events outside of its FOV. About 76.91% of the integrated LVC\nlocalization probability was outside of the BAT FOV but above the Earth's\nlimb from Swift's location, and the corresponding flux upper limits for\nthis\nregion are within roughly an order of magnitude of those within the FOV.",
  "circularId": 24158,
  "createdOn": 1556035751000,
  "email": "amy.y.lien@nasa.gov",
  "subject": "LIGO/Virgo S190421ar: Swift/BAT Counterpart Search",
  "submitter": "Amy Lien at GSFC  <amy.y.lien@nasa.gov>",
  "eventId": "LIGO/Virgo S190421ar"
}