[vsnet-grb-info 22449] LIGO/Virgo S190513bm: CALET Observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  24548
SUBJECT: LIGO/Virgo S190513bm: CALET Observations
DATE:    19/05/15 03:51:49 GMT
FROM:    Yuta Kawakubo at Louisiana State U./CALET  <kawakubo1 at lsu.edu>

T. Sakamoto, A. Yoshida, 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 S190513bm T0 = 2019-05-13 20:54:28.747 UT (The LIGO
Scientific Collaboration and Virgo Collaboration, GCN Circ. 24522). 

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 33%
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 = 355.5 deg, Dec=11.0 deg and RA = 348.0 deg, Dec = 4.3 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 
(signal-to-noise ratio >= 7) 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 low energy trigger mode
at the trigger time of S190513bm.  Using 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.

The 90% upper limit of CAL is 6.0x10^-5 erg/cm2/s (1-10 GeV) when
the summed LIGO-Virgo probability reaches 5%.  The CAL FOV was 
centered at RA = 348.0 deg, Dec = 4.4 deg at T0.