TITLE:   GCN CIRCULAR
NUMBER:  23937
SUBJECT: GRB 190306A: MAXI/GSC detection
DATE:    19/03/07 02:09:26 GMT
FROM:    H. Negoro at Nihon U.  <negoro@phys.cst.nihon-u.ac.jp>

M. Shidatsu (Ehime U.), H. Negoro (Nihon U.), M. Serino (AGU),
M. Nakajima, A. Sakamaki, W. Maruyama, M. Aoki, K. Kobayashi (Nihon U.),
T. Mihara, S. Nakahira, F. Yatabe, Y. Takao, M. Matsuoka (RIKEN),
T. Sakamoto, S. Sugita, T. Hashimoto, A. Yoshida (AGU), N. Kawai, 
M. Sugizaki, Y. Tachibana, K. Morita (Tokyo Tech), S. Ueno, H. Tomida, 
M. Ishikawa, Y. Sugawara, N. Isobe, R. Shimomukai, T. Midooka (JAXA),
Y. Ueda, A. Tanimoto, T. Morita, S. Yamada, S. Ogawa (Kyoto U.),
Y. Tsuboi, W. Iwakiri, R. Sasaki, H. Kawai, T. Sato (Chuo U.),
H. Tsunemi, T. Yoneyama, K. Asakura, S. Ide (Osaka U.), M. Yamauchi, 
K. Hidaka, S. Iwahori (Miyazaki U.), T. Kawamuro (NAOJ), 
K. Yamaoka (Nagoya U.), Y. Kawakubo (LSU)
report on behalf of the MAXI team:

The MAXI/GSC nova alert system triggered on a bright uncatalogued X-ray
transient source at 2019 March 06 UT 20:51:59.
Assuming that the source flux was constant over the transit,
we obtain the source position at
(R.A., Dec) = (222.563 deg, 30.944 deg) = (14 50 15, +30 56 38) (J2000)
with a statistical 90% C.L. elliptical error region 
with long and short radii of 0.34 deg and 0.33 deg, respectively.
The roll angle of long axis from the north direction is 142.0 deg
counterclockwise. There is an additional systematic uncertainty of 
0.1 deg (90% containment radius). The X-ray flux averaged over the scan 
was 81 +- 16 mCrab (4.0-10.0keV, 1 sigma error).
There was no significant excess flux in the previous transit at UT 19:19
and in the next transit at UT 22:24 with an upper limit of 20 mCrab for each.