TITLE: GCN CIRCULAR NUMBER: 25134 SUBJECT: LIGO/Virgo S190720a: Upper limits from CALET observations DATE: 19/07/21 04:41:47 GMT FROM: Yuta Kawakubo at Louisiana State U./CALET S. Sugita, A. Yoshida, T. Sakamoto, V. Pal'shin (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: At the trigger time of the compact binary merger candidate S190720a, T0 = 2019-07-20 00:08:36.704 UT (The LIGO Scientific Collaboration and Virgo Collaboration, GCN Circ. 25115), the CALET Gamma-ray Burst Monitor (CGBM) high voltages were off (from T0-4 min to T0+17 min). The CALET Calorimeter (CAL) was operating in the high energy trigger mode at the trigger time of S190720a. Using the 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 3.0x10^-5 erg/cm^2/s (10-100 GeV) when the summed LIGO-Virgo probability reaches 25%. The CAL FOV was centered at RA = 49.7 deg and DEC = -32.1 deg at T0.