GCN Circular 24531

A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU),
Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), 
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 S190512at T0=2019-05-12 18:07:14.422UT (The LIGO 
Scientific Collaboration and Virgo Collaboration, GCN Circ. 24503
Not found
 
 
). 

No CGBM on-board trigger occurred around the event time.  Based 
on the LIGO-Virgo localization sky map, most of the part of the high
probability area was inside of the field-of-view of SGM.  The 
summed LIGO probabilities inside the HXM and the SGM field of
view are 19% and 95% (and 0% credible region of the initial
localization map were Earth-occulted).  The HXM and SGM field of
views were centered at RA=205.5 deg, Dec = 44.8 deg and
RA=214.9 deg, Dec=37.7 deg at T0.

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 around the trigger time in either the 
HXM (7-3000 keV) or the SGM (40 keV - 28 MeV) data. 

The CALET Calorimeter (CAL) was operating in high energy trigger mode
at the trigger time of S190512at. Using CAL data, we have searched for
gamma-ray events in the 10-100 GeV band from -60 sec to +60 sec
from the GW trigger time and found no candidates.
The 90% upper limit of CAL is 1.9x10^-5 erg/cm2/s (10-100 GeV) when
the summed LIGO-Virgo probability reaches 10%.
The CAL FOV was centered at RA=214.9 deg, Dec=37.7 deg at T0.