LIGO/Virgo S190727h: Swift/BAT Counterpart Search

<somebody goes first>
S. D. Barthelmy (NASA/GSFC), A. Y. Lien (GSFC/UMBC), 
D. M. Palmer (LANL), T. Sakamoto (AGU), 
A. P. Beardmore (U. Leicester), M. G. Bernardini (INAF-OAB),
A. A. Breeveld (MSSL-UCL), D. N. Burrows (PSU), 
S. Campana (INAF-OAB), S. B. Cenko (NASA/GSFC),
G. Cusumano (INAF-IASF PA), A. D'Ai (INAF-IASFPA), 
P. D'Avanzo (INAF-OAB), V. D'Elia (ASI-SSDC), S. Emery (UCL-MSSL), 
P. A. Evans (U. Leicester), P. Giommi (ASI), C. Gronwall (PSU), 
D. Hartmann (Clemson U.), J. A. Kennea (PSU), H. A. Krimm (NSF), 
N. P. M. Kuin (UCL-MSSL), F. E. Marshall (NASA/GSFC), 
A. Melandri (INAF-OAB), J. A. Nousek (PSU), 
S. R. Oates (Uni. of Warwick), P. T. O'Brien (U. Leicester), 
J. P. Osborne (U. Leicester), C. Pagani (U. Leicester), 
K. L. Page (U.Leicester), M. J. Page (UCL-MSSL), M. Perri (ASDC), 
J. L. Racusin (NASA/GSFC), B. Sbarufatti (INAF-OAB/PSU),
M. H. Siegel (PSU), G. Tagliaferri (INAF-OAB), A. Tohuvavohu (PSU),
E. Troja (NASA/GSFC/UMCP) report on behalf of the Swift team:

We report the search results in the BAT data within T0 +/- 100 s of the
LVC event S190727h (LIGO/VIRGO Collaboration GCN Circ. XXXXX), 
where T0 is the LVC trigger time (2019-07-27T06:03:33.985 UTC).

The center of the BAT FOV at T0 is
RA = 171.271 deg,
DEC = -3.729 deg,
and the ROLL angle is 287.727 deg.
The BAT Field of View (>10% partial coding) covers 0.00% of the integrated
LVC localization probability, and 0.00% of the galaxy convolved 
probability (Evans et al. 2016).

[If there are significant detection, change the following paragraph accordingly]
Within T0 +/- 100 s, no significant detections (signal-to-noise ratio
>~ 5 sigma) are found in the BAT raw light curves with time bins of 64 ms, 
1 s, and 1.6 s. Assuming an on-axis (100% coded) short GRB with a typical 
spectrum in the BAT energy range (i.e., a simple power-law model with a 
power-law index of -1.32, Lien & Sakamoto et al. 2016), the 5-sigma upper 
limit in the 1-s binned light curve corresponds to a flux upper 
limit (15-350 keV) of ~ 6.42 x 10^-8 erg/s/cm^2.

[Description of event data analysis, if available]

BAT retains decreased, but significant, sensitivity to rate increases for
gamma-ray events outside of its FOV. About 57.30% of the integrated LVC
localization probability was outside of the BAT FOV but above the 
Earth's limb from Swift's location, and the corresponding flux upper limits 
for this region are within roughly an order of magnitude higher than those 
within the FOV.

The results of the BAT analysis are available at
https://swift.gsfc.nasa.gov/results/BATbursts/team_web/S190727h/web/source.html