[vsnet-grb-info 22119] LIGO/Virgo S190425z: CALET Observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  24218
SUBJECT: LIGO/Virgo S190425z: CALET Observations
DATE:    19/04/26 11:09:39 GMT
FROM:    Valentin Pal'shin at AGU  <val at phys.aoyama.ac.jp>

Y. Shimizu (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),
T. Tamura (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 S190425z,
T0=2019-04-25 08:18:05.017 UTC (The LIGO Scientific Collaboration and
Virgo Collaboration, GCN Circ. 24168), the high-voltage of the CALET
Gamma-ray Burst Monitor (CGBM) detectors were off
(from T0-192 sec to T0+1084 sec).

The CALET Calorimeter (CAL) was operating in high energy trigger mode
at the trigger time of S190425z. 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 1.0x10^-4 erg/cm2/s (10-100 GeV) when
the summed LIGO-Virgo probability reaches 5%.
The CAL FOV was centered at RA=131.3 deg, Dec=-43.6 deg at T0.