Skip to main content
Introducing Einstein Probe, Astro Flavored Markdown, and Notices Schema v4.0.0. See news and announcements

GCN Circular 35214

Subject
GRB 231129B: MAXI/GSC detection
Date
2023-11-29T15:23:40Z (7 months ago)
From
Motoko Serino at Aoyama Gakuin U. <serino@phys.aoyama.ac.jp>
Via
Web form
M. Kurihara (JAXA), H. Negoro (Nihon U.), M. Serino (AGU), W. Iwakiri (Chiba U.),
M. Nakajima, K. Kobayashi, M. Tanaka, Y. Soejima, Y. Kudo (Nihon U.), 
T. Mihara, T. Kawamuro, S. Yamada, T. Tamagawa, N. Kawai, M. Matsuoka (RIKEN), 
T. Sakamoto, S. Sugita, H. Hiramatsu, H. Nishikawa, A. Yoshida (AGU), 
Y. Tsuboi, S. Urabe, S. Nawa, N. Nemoto, E.Goto (Chuo U.), 
M. Shidatsu (Ehime U.),
I. Takahashi, M. Niwano, S. Sato, N. Higuchi, Y. Yatsu (Tokyo Tech), 
S. Nakahira,  S. Ueno, H. Tomida, M. Ishikawa, S. Ogawa, M. Kurihara (JAXA), 
Y. Ueda, K. Setoguchi, T. Yoshitake, Y. Nakatani, Y. Okada (Kyoto U.), 
M. Yamauchi, Y. Hagiwara, Y. Umeki, Y. Otsuki (Miyazaki U.), 
K. Yamaoka (Nagoya U.),
Y. Kawakubo (LSU),
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 14:03:05 UT on 29 November 2023.
Assuming that the source flux was constant over the transit,
we obtain the source position at
(R.A., Dec) = (285.662 deg, 40.278 deg) = (19 02 38, +40 16 40) (J2000)
with a statistical 90% C.L. elliptical error region
with long and short radii of 0.39 deg and 0.26 deg, respectively.
The roll angle of long axis from the north direction is 75.0 deg counterclockwise.
Without assumptions on the source constancy, we obtain a rectangular error
box for the transient source with the following corners:
(283.889, 39.749) deg = (18 55 33, +39 44 56) (J2000)
(284.232, 39.302) deg = (18 56 55, +39 18 07) (J2000)
(286.730, 40.399) deg = (19 06 55, +40 23 56) (J2000)
(286.398, 40.853) deg = (19 05 35, +40 51 10) (J2000)
There is an additional systematic uncertainty of 0.1 deg (90% containment radius).

The X-ray flux averaged over the scan was 141 +- 32 mCrab
(4.0-10.0keV, 1 sigma error).
There was no significant excess flux in the previous transit at 12:30 UT
with an upper limit of 20 mCrab.
Looking for U.S. government information and services? Visit USA.gov