MAXI/GSC detection of renewed activity from XTE J1908+094/MAXI J1909+094

ATel #14912; K. Kobayashi, H. Negoro (Nihon U.), S. Ogawa (Kyoto U.), M. Nakajima, K. Asakura, K. Seino (Nihon U.), T. Mihara, T. Tamagawa, M. Matsuoka (RIKEN), T. Sakamoto, M. Serino, S. Sugita, K. Komachi, A. Yoshida (AGU), Y. Tsuboi, W. Iwakiri, H. Kawai, Y. Okamoto, S. Kitakoga (Chuo U.), M. Shidatsu (Ehime U.), N. Kawai, M. Niwano, R. Hosokawa (Tokyo Tech), S. Nakahira, S. Ueno, H. Tomida, M. Ishikawa, M. Tominaga, T. Nagatsuka, T. Omama, M. Kurihara (JAXA), Y. Ueda, S. Yamada, K. Setoguchi, T. Yoshitake, Y. Goto, R. Uematsu (Kyoto U.), H. Tsunemi (Osaka U.), M. Yamauchi, Y. Nonaka, T. Sato, R. Hatsuda, R. Fukuoka (Miyazaki U.), T. Kawamuro (UDP/NAOJ), K. Yamaoka (Nagoya U.), Y. Kawakubo (LSU), M. Sugizaki (NAOC) report on behalf of the MAXI team
on 13 Sep 2021; 15:02 UT
Credential Certification: Hitoshi Negoro (negoro@phys.cst.nihon-u.ac.jp)

Tweet

The MAXI/GSC nova alert system triggered on a hard X-ray transient source at 20:11 on September 12, 2021. Assuming that the source flux was constant over eleven scan transits from 12:26 on September 12 to 3:56 on September 13, we obtain the source position at

(R.A., Dec) = (287.424 deg, 9.427 deg) = (19 09 41, +09 25 37) (J2000)

with a statistical 90% C.L. elliptical error region with long and short radii of 0.33 deg and 0.2 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). The X-ray flux averaged over the scans was 43 +/- 6 mCrab (4.0-10.0keV, 1 sigma error). The X-ray activity started on September 12, and the X-ray flux changes largely on timescales of hours.

The error region includes the microquasar XTE J1908+094 discovered in 2002 (In't Zand, et. al, IAUC 7873 ). Outbursts from XTE J1908+094 were observed in 2013 (ATel #5523, #5549) and in 2019 (ATel #12628, #12632, #12652). The Swift/BAT light curve of XTE J1908+094, however, does not shows any significant activity, yet (https://swift.gsfc.nasa.gov/results/transients/weak/XTEJ1908p094/). Thus, we also tentatively name the source MAXI J1909+094.

Followup observations are encouraged to identify this source.

Trigger Information about this transient