TITLE:   GCN CIRCULAR
NUMBER:  27790
SUBJECT: CGBM-SPI-ACS triangulation of short GRB 200521A
DATE:    20/05/23 13:27:33 GMT
FROM:    Valentin Pal'shin at AGU  <val@phys.aoyama.ac.jp>

T. Sakamoto, A. Yoshida, V. Pal'shin, S. Sugita (AGU),
Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN),
Y. Asaoka, 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:


Using the CALET Gamma-Ray Burst Monitor (CGBM) event data and
publicly available INTEGRAl-SPI-ACS light curve data we have triangulated
the bright short hard GRB 200521A (AGILE/MCAL and ratemeters detection:
Verrecchia et al., GCN Circ. 27776; CGBM detection: Yoshida et al.,
GCN Circ. 27777) to a preliminary CGBM-SPI-ACS annulus centered at
RA(J2000)=86.570 deg (05h 46m 17s) Dec(J2000)= -34.390 deg (-34d 23' 24"),
whose radius is 88.32(-1.63,+1.63) deg (3 sigma).

The CGBM response also suggests the burst source was in the FOV of the
CGBM HXM detectors, i.e. within 60 deg from RA, Dec(J2000) = 112.49 deg,
+5.67 deg (=the center of the FOV).

The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at the Waseda University.

The INTEGRAL-SPI-ACS data used in this analysis were obtained from
the INTEGRAL data archive through 
http://isdc.unige.ch/~savchenk/spiacs-online/
maintained by Volodymyr Savchenko.