MAXI/GSC detection of an X-ray burst probably from XTE J1810-189
ATel #16000; K. Kobayashi, H. Negoro, M. Nakajima, M. Tanaka, Y. Soejima, Y. Kudo (Nihon U.), T. Mihara, T. Kawamuro, S. Yamada, T. Tamagawa, N. Kawai, M. Matsuoka (RIKEN), T. Sakamoto, M. Serino, S. Sugita, H. Hiramatsu, H. Nishikawa, A. Yoshida (AGU), Y. Tsuboi, S. Urabe, S. Nawa, N. Nemoto (Chuo U.), M. Shidatsu (Ehime U.), M. Niwano, S. Sato, N. Higuchi (Tokyo Tech), S. Nakahira, S. Ueno, H. Tomida, M. Ishikawa, T. Kurihara (JAXA), Y. Ueda, S. Ogawa, K. Setoguchi, T. Yoshitake, K. Inaba, Y. Nakatani (Kyoto U.), M. Yamauchi, Y. Hagiwara, Y. Umeki, Y. Otsuki (Miyazaki U.), K. Yamaoka (Nagoya U.), Y. Kawakubo (LSU), M. Sugizaki (NAOC), and W. Iwakiri (Chiba U.)
on 21 Apr 2023; 10:43 UT
Credential Certification: Hitoshi Negoro (negoro@phys.cst.nihon-u.ac.jp)
Subjects: X-ray, Neutron Star
The MAXI/GSC detected an X-ray burst-like event in the scan transit at 20:09 UT on 2023 April 19. Assuming that the source flux was constant over the transient, We obtain the source position at
(R.A., Dec) = (272.498 deg, -19.211 deg) = (18 09 59, -19 12 39) (J2000)
with a statistical 90% C.L. elliptical error region with long and short radii of 0.16 deg and 0.14 deg, respectively. The roll angle of the long axis from the north direction is 38.0 deg counterclockwise. There is an additional systematic uncertainty of 0.1 deg (90% containment radius). However, the X-ray flux rapidly increased and decreased in about 20 sec during about 50 sec scanning observation, which means that a strict error region is larger than the above estimation. The X-ray flux averaged over the scan was 358 +- 37 mCrab (4.0-10.0keV, 1 sigma error). A faint activity with 41 +- 16 mCrab is also recognized in the scan transit at 2:21 on April 20.
The error region includes the LMXB XTE J1810-189 discovered in 2008 (ATel #1424). An X-ray burst from XTE J1810-189 was observed in 2008 (ATel #1443, Weng et al. 2015, MNRAS, 450, 2915). If we assume that this burst source is XTE J1810-189 and effective are correction is applied, the peak flux of this burst is about 1 Crab. Though the peak flux is about half of a burst peak flux in 2008 (Weng et al. 2015), the burst duration and the double-peaked structure just like seen in the burst in 2008 suggest the source is XTE J1810-189. If the source is XTE J1810-189, this may be the beginning of renewed activity since 2013 (ATel #4752, #4804). We also tentatively name the source MAXI J1809-192.
Burst information
