MAXI/GSC detection of renewed activity of the black hole X-ray binary V4641 Sgr
ATel #16804; H. Negoro, M. Nakajima (Nihon U.), K. Fujiwara (Kyoto U.), Y. Kudo, H. Shibui, K. Takagi, H. Takahashi, K. Tatano, H. Nishio (Nihon U.), T. Mihara, T. Kawamuro, S. Yamada, S. Wang, T. Tamagawa, N. Kawai, M. Matsuoka (RIKEN), T. Sakamoto, M. Serino, S. Sugita, Y. Kawakubo, H. Hiramatsu, H. Nishikawa, Y. Kondo, A. Yoshida (AGU), Y. Tsuboi, H. Sugai, N. Nagashima (Chuo U.), M. Shidatsu, Y. Niida (Ehime U.), I. Takahashi, M. Niwano, N. Higuchi, Y. Yatsu (Tokyo Tech), S. Nakahira, S. Ueno, H. Tomida, M. Ishikawa, S. Ogawa, M. Kurihara (JAXA), Y. Ueda, Y. Okada (Kyoto U.), M. Yamauchi, Y. Otsuki, T. Hasegawa, M. Nishio (Miyazaki U.), K. Yamaoka (Nagoya U.), M. Sugizaki (Kanazawa U.), and W. Iwakiri (Chiba U.)
on 6 Sep 2024; 10:37 UT
Credential Certification: Hitoshi Negoro (negoro@phys.cst.nihon-u.ac.jp)
Subjects: X-ray, Black Hole
The MAXI/GSC nova alert system triggered on a soft X-ray transient source at 01:15 UT on September 6, 2024 in the 2-4 keV and 3-10 keV bands. Assuming that the source flux was constant over the eight transits from 6:40 on Sep. 5 to 5:54 on Sep.6, we obtain the source position in the 2-10 keV band at
(R.A., Dec) = (274.651 deg, -25.314 deg) = (18 18 36, -25 18 49) (J2000)
with a 90% C.L. statistical error of 0.24 deg and an additional systematic uncertainty of 0.1 deg (90% containment radius). The X-ray flux averaged over the scans was 21 +- 4 mCrab (2.0-4.0 keV, 1 sigma error). The X-ray brightening likely started from September 3.
The localized position and a soft X-ray spectrum are consistent with those of the black hole X-ray binary Sgr V4641. The last outburst from this source was in October 2021 (ATel #14968, #14971, #14992, #15010, #15023). Followup observations are encouraged.
Trigger Information about V4641 Sgr
