MAXI/GSC detection of a new hard X-ray transient MAXI J0655-013
ATel #15442; M. Serino (AGU), H. Negoro, M. Nakajima, K. Kobayashi, M. Tanaka, Y. Soejima (Nihon U.), T. Mihara, T. Kawamuro, S. Yamada, T. Tamagawa, M. Matsuoka (RIKEN), T. Sakamoto, S. Sugita, H. Hiramatsu, A. Yoshida (AGU), Y. Tsuboi, W. Iwakiri, J. Kohara (Chuo U.), M. Shidatsu, M. Iwasaki (Ehime U.), N. Kawai, M. Niwano, R. Hosokawa, Y. Imai, N. Ito, Y. Takamatsu (Tokyo Tech), S. Nakahira, S. Ueno, H. Tomida, M. Ishikawa, M. Tominaga, T. Nagatsuka, T. Kurihara (JAXA), Y. Ueda, S. Ogawa, K. Setoguchi, T. Yoshitake, K. Inaba (Kyoto U.), H. Tsunemi (Osaka U.), M. Yamauchi, T. Sato, R. Hatsuda, R. Fukuoka, Y. hagiwara, Y. Umeki (Miyazaki U.), K. Yamaoka (Nagoya U.), Y. Kawakubo (LSU) and M. Sugizaki (NAOC).
on 19 Jun 2022; 16:44 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 nova alert system triggered on a bright uncatalogued X-ray transient source at 10:23 UT on June 18, 2022. Assuming that the source flux was constant over four transits from 10:23 to 15:02 on June 18, we obtain the source position at
(R.A., Dec) = (103.865 deg, -1.398 deg) = (06 55 27, -01 23 52) (J2000)
with a statistical 90% C.L. elliptical error region with long and short radii of 0.17 deg and 0.14 deg, respectively. The roll angle of long axis from the north direction is 145.0 deg counterclockwise. There is an additional systematic uncertainty of 0.1 deg (90% containment radius). The X-ray flux averaged over the scans was 61 +- 8 mCrab (4.0-10.0keV, 1 sigma error).
We note that the Swift/BAT also triggered this source at 20:26 on June 18 (https://gcn.gsfc.nasa.gov/other/1110865.swift).
The source has a very hard spectrum, suggesting the source to be an X-ray pulsar or a black hole X-ray binary in the hard state. Since there is no known bright X-ray source in the error region, we tentatively name the source MAXI J0655-013.
Followup observations are strongly encouraged.
Trigger Information about MAXI J0655-013
