GRB 211115A

M. Serino (AGU), Y. Kawakubo (LSU),
H. Negoro, M. Nakajima, K. Kobayashi, K. Asakura, K. Seino (Nihon U.),
T. Mihara, T. Tamagawa, M. Matsuoka (RIKEN),
T. Sakamoto, S. Sugita, K. Komachi, H. Hiramatsu, A. Yoshida (AGU),
Y. Tsuboi, W. Iwakiri, H. Kawai, Y. Okamoto, S. Kitakoga (Chuo U.),
M. Shidatsu (Ehime U.),
N. Kawai, M. Niwano, R. Hosokawa (Tokyo Tech),
S. Nakahira, S. Ueno, H. Tomida, M. Ishikawa, M. Tominaga, T. Nagatsuka, M. Kurihara (JAXA),
Y. Ueda, S. Yamada, S. Ogawa, K. Setoguchi, T. Yoshitake, Y. Goto, R. Uematsu, K. Inaba (Kyoto U.),
H. Tsunemi (Osaka U.),
M. Yamauchi, Y. Nonaka, T. Sato, R. Hatsuda, R. Fukuoka (Miyazaki U.), T. Kawamuro (UDP/NAOJ),
K. Yamaoka (Nagoya U.),
M. Sugizaki (NAOC) 
report on behalf of the MAXI team:

The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray transient source at 2021-11-15T16:31:19 UT.
Assuming that the source flux was constant over the transit,
we obtain the source position at
(R.A., Dec) = (122.977 deg, -25.709 deg) = (08 11 54, -25 42 32) (J2000)
with a statistical 90% C.L. elliptical error region
with long and short radii of 0.13 deg and 0.11 deg, respectively.
The roll angle of long axis from the north direction is 61.0 deg counterclockwise.
There is an additional systematic uncertainty of 0.1 deg (90% containment radius).
Without assumptions on the source constancy, we obtain a rectangular error
box for the transient source with the following corners:
(122.347, -24.737) deg = (08 09 23, -24 44 13) (J2000)
(122.123, -24.889) deg = (08 08 29, -24 53 20) (J2000)
(123.589, -26.633) deg = (08 14 21, -26 37 58) (J2000)
(123.815, -26.479) deg = (08 15 15, -26 28 44) (J2000).
The X-ray flux averaged over the scan was 336 +- 35 mCrab
(4.0-10.0keV, 1 sigma error).
There was no significant excess flux in the previous transit at 14:58 UT
with an upper limit of 20 mCrab.

Y. Shimizu (Kanagawa U),
A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU),
Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN),
Y. Asaoka (ICRR), S. Torii, Y. Akaike, K. Kobayashi (Waseda U),
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 long GRB 211115A (MAXI/GSC detection: Serino et al., GCN Circ. 31082
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 ;
Fermi-GBM trigger #658686687) was detected in ground analysis
of the CALET Gamma-ray Burst Monitor (CGBM) data near the MAXI trigger time
at 16:31:19 UTC on 15 November 2021.
The burst signal was weakly seen by all CGBM detectors.

The burst light curve shows a single pulse with a duration of ~10 sec.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1321029033/

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