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GCN Circular 24495

LIGO/Virgo S190510g: CALET Observations
2019-05-12T03:01:00Z (5 years ago)
Yuta Kawakubo at Louisiana State U./CALET <>
P. S. Marrocchesi (U of Siena), 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,
T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC), 
M. L. Cherry (LSU), S. Ricciarini (U of Florence),
and the CALET collaboration:

The CALET Gamma-ray Burst Monitor (CGBM) was operating at the 
trigger time of S190510g T0=2019/05/10 02:59:39.292 UT (The LIGO 
Scientific Collaboration and Virgo Collaboration, GCN Circ. 24442, 
24448 and 24462).  

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 outside of the field-of-view of CGBM.  The 
summed LIGO probabilities inside the HXM and the SGM field of
view are 2% and 7% (and 84% credible region of the updated
localization map were Earth-occulted).  The HXM and SGM field of
views were centered at RA=298.7 deg, Dec = 60.7 deg and
RA=295.7 deg, Dec=50.8 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 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 high energy trigger
mode at the trigger time of S190510g. 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.  There is no significant overlap with the LVC location 
probability map.  The CAL FOV was centered at RA=295.7 deg, 
Dec=50.8 deg at T0.
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