Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to https://gcn.nasa.gov.
New Announcement Feature, Code of Conduct, Circular Revisions. See news and announcements

GCN Circular 27960

Subject
GRB 200615B: MAXI/GSC detection
Date
2020-06-16T01:40:27Z (4 years ago)
From
Hitoshi Negoro at Nihon U <negoro.hitoshi@nihon-u.ac.jp>
K. Miike (Miyazaki U.), H. Negoro (Nihon U.), Y. Kawakubo (LSU), 
M. Nakajima, M. Aoki, K. Kobayashi, R. Takagi, K, Asakura, 
K, Seino, S. Mokumoto (Nihon U.), 
T. Mihara, C. Guo, Y. Zhou, T. Tamagawa, M. Matsuoka (RIKEN), 
T. Sakamoto, M. Serino, S. Sugita, H. Nishida, A. Yoshida (AGU), 
Y. Tsuboi, W. Iwakiri, R. Sasaki, H. Kawai, Y. Okamoto, S. Kitakoga (Chuo U.), 
M. Shidatsu (Ehime U.), N. Kawai, R. Adachi, M. Niwano (Tokyo Tech), 
S. Nakahira, Y. Sugawara, S. Ueno, H. Tomida, M. Ishikawa, M. Tominaga, T. Nagatsuka (JAXA), 
Y. Ueda, S. Yamada, S. Ogawa, K. Setoguchi, T. Yoshitake (Kyoto U.), 
H. Tsunemi (Osaka U.), M. Yamauchi, K. Kurogi (Miyazaki U.), 
T. Kawamuro (NAOJ), K. Yamaoka (Nagoya U.), M. Sugizaki (NAOC) 
report on behalf of the MAXI team:

The MAXI/GSC nova alert system triggered on an uncatalogued X-ray transient source 
at 10:30:18 UT on 2020 June 15.
Assuming that the source flux was constant over the transit,
we obtain the source position at
(R.A., Dec) = (153.421 deg, -5.158 deg) = (10 13 41, -05 09 28) (J2000) 
with a statistical 90% C.L. elliptical error region 
with long and short radii of 0.34 deg and 0.3 deg, respectively. 
The roll angle of the long axis from the north direction is 180.0 deg counterclockwise. 
Without assumptions on the source flux constancy, we obtain a rectangular error
box for the transient source with the following corners:
(R.A., Dec) = (152.024, -3.311) deg = (10 08 05, -03 18 39) (J2000) 
(R.A., Dec) = (151.564, -3.753) deg = (10 06 15, -03 45 10) (J2000) 
(R.A., Dec) = (153.538, -5.793) deg = (10 14 09, -05 47 34) (J2000) 
(R.A., Dec) = (153.998, -5.350) deg = (10 15 59, -05 20 59) (J2000) 
There is an additional systematic uncertainty of 0.1 deg (90% containment radius)
in both error regions.

The X-ray flux averaged over the scan was 85 +- 19 mCrab
(4.0-10.0keV, 1 sigma error).

There was no significant excess flux in the previous transit at 08:57 UT
and in the next transit at 12:03 UT with an upper limit of 20 mCrab for each.
Looking for U.S. government information and services? Visit USA.gov