MAXI/GSC detection of a new X-ray transient MAXI J1813-095
ATel #11323; T. Kawase, H. Negoro (Nihon U.), T. Yoneyama (Osaka U.), S. Ueno, H. Tomida, M. Ishikawa, Y. Sugawara, N. Isobe, R. Shimomukai (JAXA), T. Mihara, M. Sugizaki, S. Nakahira, W. Iwakiri, F. Yatabe, Y. Takao, M. Matsuoka (RIKEN), N. Kawai, S. Sugita, T. Yoshii, Y. Tachibana, S. Harita, K. Morita (Tokyo Tech), A. Yoshida, T. Sakamoto, M. Serino, Y. Kawakubo, Y. Kitaoka, T. Hashimoto (AGU), H. Tsunemi (Osaka U.), M. Nakajima, A. Sakamaki, W. Maruyama (Nihon U.), Y. Ueda, T. Hori, A. Tanimoto, S. Oda, T. Morita, S. Yamada (Kyoto U.), Y. Tsuboi, Y. Nakamura, R. Sasaki, H. Kawai, T. Sato (Chuo U.), M. Yamauchi, C. Hanyu, K. Hidaka (Miyazaki U.), T. Kawamuro (NAOJ), K. Yamaoka (Nagoya U.), M. Shidatsu (Ehime U.) report on behalf of the MAXI team:
on 20 Feb 2018; 10:52 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Hitoshi Negoro (negoro@phys.cst.nihon-u.ac.jp)
Subjects: X-ray, Black Hole, Neutron Star, Transient
The MAXI/GSC detected a probable new X-ray transient on 2018 February 19. Using data of 11 scan transits from 15:49 UT on February 19 to 08:48 on February 20 and assuming that the source flux was constant over each scan transit, we obtain the source position at
(R.A., Dec) = (273.403 deg, -9.540 deg) = (18 13 36, -09 32 23) (J2000)
with a statistical 90% C.L. elliptical error region with long and short radii of 0.28 deg and 0.21 deg, respectively. The roll angle of the long axis from the north direction is 159.0 deg counterclockwise. There is an additional systematic uncertainty of 0.1 deg (90% containment radius). The X-ray flux averaged over the 11 scan transits was 23 +- 4 mCrab (4.0-10.0keV, 1 sigma error).
A quick-look analysis shows that the source flux has increased since the beginning of 2018 February 19, and reached approximately 30 mCrab at 4-10 keV band on February 20.
Since there is no known X-ray source in the error region, we tentatively name the source MAXI J1813-095.
Follow-up observations are encouraged to understand the nature of this new transient.
Flash Report for MAXI J1813-095
