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GCN Circular 25734

Subject
LIGO/Virgo S190910d: No transient candidates in CALET observations.
Date
2019-09-13T03:22:51Z (5 years ago)
From
Yuta Kawakubo at Louisiana State U./CALET <kawakubo1@lsu.edu>
S. Ricciarini (U of Florence),  A. Yoshida, T. Sakamoto, 
V. Pal'shin, S. Sugita (AGU),  Y. Kawakubo (LSU), 
K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), Y. Asaoka,
S. Torii (Waseda U), Y. Shimizu,  T. Tamura (Kanagawa U),
N. Cannady (GSFC/UMBC),  M. L. Cherry (LSU),
P. S. Marrocchesi (U of Siena),
and the CALET collaboration:

The CALET Gamma-ray Burst Monitor (CGBM) was operating at the trigger 
time of S190910d T0 = 2019-09-10 01:26:19.243 UT (The LIGO Scientific
Collaboration and Virgo Collaboration, GCN Circ. 25695 and 25723).

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 1 % and 64 %, respectively (and 77 % credible region of the 
updated localization map was above the horizon).  The HXM and SGM 
fields of view were centered at RA = 108.8 deg, Dec = 29.9 deg and 
RA = 100.8 deg, Dec = 22.9 deg at T0, respectively.

The CALET Calorimeter (CAL) was operating in the low energy
trigger mode at the trigger time of S190910d. Using the CAL data,
we have searched for gamma-ray events in the 1-10 GeV band 
from -60 sec to +60 sec from the GW trigger time and found no
candidates. There is no significant overlap with the LIGO-Virgo
high probability localization region.  The CAL FOV was centered at 
RA=100.8 deg, Dec=22.9 deg at T0.
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