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

GCN Circular 36485

GRB 240514E: MAXI/GSC detection of a probable afterglow
2024-05-15T14:59:05Z (2 months ago)
Hitoshi Negoro at Nihon University/MAXI team <>
Web form
H. Negoro (Nihon. U). S. Ogawa (JAXA), W. Iwakiri (Chiba U.), M. Nakajima, Y. Kudo, H. Shibui, 
K. Takagi, H. Takahashi, K. Tatano, H. Nishio (Nihon U.), T. Mihara, T. Kawamuro, S. Yamada, 
S. Wang, T. Tamagawa, N. Kawai, M. Matsuoka (RIKEN),T. Sakamoto, M. Serino, S. Sugita, Y. Kawakubo, 
H. Hiramatsu, H. Nishikawa, Y. Kondo, A. Yoshida (AGU), Y. Tsuboi, H. Sugai, N. Nagashima (Chuo U.), 
M. Shidatsu, Y. Niida (Ehime U.),I. Takahashi, M. Niwano, S. Sato, N. Higuchi, Y. Yatsu (Tokyo Tech), 
S. Nakahira, S. Ueno, H. Tomida, M. Ishikawa, M. Kurihara (JAXA), Y. Ueda, Y. Okada (Kyoto U.), 
M. Yamauchi, Y. Otsuki, T. Hasegawa, M. Nishio (Miyazaki U.), K. Yamaoka (Nagoya U.), and 
M. Sugizaki (NAOC)

The MAXI/GSC detected an uncatalogued X-ray transient source at 19:04 UT 
on May 14, 2024. Assuming that the source flux was constant over the transit,
we obtain the source position at
(R.A., Dec) = (76.718 deg, -21.544 deg) = (05 06 52, -21 32 38) (J2000) 
with a statistical 90% C.L. elliptical error region 
with long and short radii of 0.61 deg and 0.42 deg, respectively. 
The roll angle of long axis from the north direction is 131.0 deg counterclockwise. 
There is an additional systematic uncertainty of 0.1 deg (90% containment radius).
The X-ray flux averaged over the scan was 100 +- 23 mCrab
(4.0-10.0keV, 1 sigma error).
There was no significant excess flux in the previous transit at 17:32 UT 
with an upper limit of 20 mCrab. No observation for the region was made 
for more than 19 hours after the detection.

The source did not show significant rapid variations during the scan.
Given a relatively high galactic longitude, (l, b) = (222.1, -32.2), 
and the spectral softness, the source is most likely a GRB afterglow.
Looking for U.S. government information and services? Visit