[vsnet-grb-info 22177] LIGO/Virgo S190426c: CALET Observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  24276
SUBJECT: LIGO/Virgo S190426c: CALET Observations
DATE:    19/04/27 10:07:20 GMT
FROM:    Valentin Pal'shin at AGU  <val at phys.aoyama.ac.jp>

T. Tamura (Kanagawa U),
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 (Kanagawa U), N. Cannady, M. L. Cherry (LSU),
S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena)
and the CALET collaboration:

At the trigger time of the compact binary merger candidate S190426c,
T0=2019-04-26 15:21:55.337 UTC (The LIGO Scientific Collaboration and
Virgo Collaboration, GCN Circ. 24237), the high-voltage of the CALET
Gamma-ray Burst Monitor (CGBM) detectors were off
(from T0-19 min to T0+10 min).

The CALET Calorimeter (CAL) was operating in high energy trigger mode
at the trigger time of S190426c. Using the CAL data, we have searched for
gamma-ray events in the 10-100 GeV band within the time interval
T0 +/- 60 sec and found no candidates.
The 90% upper limit of CAL is 2.5x10^-5 erg/cm2/s (10-100 GeV) when
the summed LIGO-Virgo probability reaches 10%.
The CAL FOV was centered at RA=183.0 deg, Dec=-50.9 deg at T0.