GCN Circular 15868

GRB 140221A: MAXI/GSC detection

Y. Morooka (Miyazaki U.), H. Negoro (Nihon U.), Y. Ogawa (Miyazaki U.), 
S. Ueno, H. Tomida, S. Nakahira, M. Kimura, M. Ishikawa, Y. E. Nakagawa (JAXA),
T. Mihara, M. Sugizaki, M. Morii, M. Serino,  J. Sugimoto, T. Takagi, A. Yoshikawa, M. Matsuoka (RIKEN),
N. Kawai, R. Usui, T. Yoshii, Y. Tachibana (Tokyo Tech), 
A. Yoshida, T. Sakamoto, Y. Nakano, Y. Kawakubo, A. Kawagoe,H. Ohtsuki (AGU), 
H. Tsunemi, M. Sasaki (Osaka U.), 
M. Nakajima, H. Sakakibara, T. Onodera, K. Fukushima, K. Suzuki (Nihon U.), 
Y. Ueda, M. Shidatsu, T. Kawamuro, T. Hori (Kyoto U.), 
Y. Tsuboi, M. Higa (Chuo U.), 
M. Yamauchi, K. Yoshidome, H. Yamada (Miyazaki U.), 
K. Yamaoka (Nagoya U.)
report on behalf of the MAXI team:

The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray transient source at UT 2014-02-21 T07:12:50.
Assuming that the source flux was constant over the transit,
we obtain the source position at
(R.A., Dec) = (107.447 deg, -17.336 deg) = (07 09 47, -17 20 09) (J2000)
with a statistical 90% C.L. elliptical error region
with long and short radii of 0.40 deg and 0.34 deg, respectively.
The roll angle of the long axis from the north direction is 146.0 deg counterclockwise.
There is an additional systematic uncertainty of 0.1 deg (90% containment  radius).
The X-ray flux averaged over the scan was 68 +- 18 mCrab
(4-10keV, 1 sigma error).
There was no significant excess flux in the previous transit at UT 5:40.