GCN Circular 24648
Subject
LIGO/Virgo S190521g: Upper limits from CALET observations
Date
2019-05-22T03:01:56Z (5 years ago)
From
Yuta Kawakubo at Louisiana State U./CALET <kawakubo1@lsu.edu>
Y. Asaoka (Waseda U), A. Yoshida, T. Sakamoto,
V. Pal'shin, S. Sugita (AGU), Y. Kawakubo (LSU),
K. Yamaoka (Nagoya U), S. Nakahira (RIKEN),
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:
At the trigger time of the compact binary merger candidate S190521g,
T0 = 2019-05-21 03:02:29.447 UT (The LIGO Scientific Collaboration
and Virgo Collaboration, GCN Circ. 24621), the CALET Gamma-ray
Burst Monitor (CGBM) high voltages were off (from T0-8 min to
T0+8 min).
The CALET Calorimeter (CAL) was operating in the high energy trigger
mode at the trigger time of S190521g. 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 6.0x10^-6 erg/cm2/s (10-100 GeV) when the
summed LIGO-Virgo probability reaches 30%. The CAL FOV was
centered at RA=205.7 deg, Dec=49.2 deg at T0.