[vsnet-grb-info 23085] LIGO/Virgo S190727h: No transient candidates in CALET observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  25184
SUBJECT: LIGO/Virgo S190727h: No transient candidates in CALET observations 
DATE:    19/07/28 07:22:48 GMT
FROM:    Yuta Kawakubo at Louisiana State U./CALET  <kawakubo1 at lsu.edu>

K. Yamaoka (Nagoya U), A. Yoshida, T. Sakamoto, 
V. Pal'shin, S. Sugita (AGU), Y. Kawakubo (LSU),
S. Nakahira (RIKEN), Y. Asaoka, S. Ozawa, S. Torii (Waseda U),
Y. Shimizu,  T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC), 
M. L. Cherry (LSU), S. Ricciarini (U of Florence),
P. S. Marrocchesi (U of Siena),
and the CALET collaboration:

The CALET Gamma-ray Burst Monitor (CGBM) was operating at the trigger 
time of S190727h T0 = 2019-07-27 06:03:33.986 UT (The LIGO
Scientific Collaboration and Virgo Collaboration, GCN Circ. 25164).

No CGBM on-board trigger occurred around the event time.  Based
on the LIGO-Virgo localization sky map, the summed LIGO probabilities 
inside the CGBM HXM (7 - 3000 keV) and SGM (40 keV - 28 MeV) fields 
of view are 0 % and 34 %, respectively (and 35 % credible region of the 
initial localization map was above the horizon).  The HXM and SGM fields
of view were centered at RA = 191.8 deg, Dec = 45.3 deg and 
RA = 201.2 deg, Dec = 38.2 deg at T0, respectively.

Based on the analysis of the light curve data with 0.125 sec
time resolution from T0-60 sec to T0+60 sec, we found no
significant excess (signal-to-noise ratio >= 7) around the trigger
time in either the HXM or the SGM data.

The CALET Calorimeter (CAL) was operating in the high energy
trigger mode at the trigger time of S190727h, but the CAL FOV
does not have any overlap with LVC probability significance map.
The CAL FOV was centered at RA= 201.1 deg, DEC= 38.2 deg at T0.