MAXI/GSC detection of X-ray rebrightening of the neutron X-ray binary XTE J1739-285
ATel #13656; H. Negoro (Nihon U.), J. A. Kennea (PSU), M. Nakajima, M. Aoki, K. Kobayashi, R. Takagi, K, Asakura, K, Seino, S. Mokumoto (Nihon U.), T. Mihara, C. Guo, Y. Zhou, T. Tamagawa, M. Matsuoka (RIKEN), T. Sakamoto, M. Serino, S. Sugita, H. Nishida, A. Yoshida (AGU), Y. Tsuboi, W. Iwakiri, R. Sasaki, H. Kawai, Y. Okamoto, S. Kitakoga (Chuo U.), M. Shidatsu (Ehime U.), N. Kawai, R. Adachi, M. Niwano (Tokyo Tech), S. Nakahira, Y. Sugawara, S. Ueno, H. Tomida, M. Ishikawa, M. Tominaga, T. Nagatsuka (JAXA), Y. Ueda, S. Yamada, S. Ogawa, K. Setoguchi, T. Yoshitake (Kyoto U.), H. Tsunemi (Osaka U.), M. Yamauchi, K. Kurogi, K. Miike (Miyazaki U.), T. Kawamuro (NAOJ), K. Yamaoka (Nagoya U.), Y. Kawakubo (LSU), and M. Sugizaki (NAOC)
on 23 Apr 2020; 15:17 UT
Credential Certification: Hitoshi Negoro (negoro@phys.cst.nihon-u.ac.jp)
Subjects: X-ray, Neutron Star
The MAXI/GSC detects X-ray rebrightening of the X-ray transient neutron star binary XTE J1739-285. This ongoing outburst of XTE J1739-285 was first detected with INTEGRAL/JEM-X on 2019 September 27 (ATel #13138, #13148, #13177, #13474, #13483, #13538). The 2-10 keV X-ray flux observed with the GSC shows the flux peak at approximately 90 mCrab on around 2019 October 8. After that, with some large variations (ATel #13474), the X-ray flux roughly exponentially decayed to less than 10 mCrab at the beginning this April. The 2-10 keV increased again from April 14, and reached 63 +/- 5 mCrab on April 20.
We requested ToO observations to the Neil Gehrels Swift Observatory to confirm this new activity from XTE J1739-285. The XRT observations starting from 19:06 on April 22 clearly detected a bright point source positionally consistent with XTE J1739-285. The XRT spectrum can be represented by an absorbed power-law with a photon index of 2.15 (+0.31, -0.29) and N_H of 4.0 (+0.7, -0.7)e22 cm^-2. The observed and unabsorbed fluxes at 0.3-10 keV are 2.2e-9 erg/cm2/s and 6.8e-9 erg/cm2/s, respectively.
We thank the Swift team for the prompt observations.
MAXI GSC data for XTE J1739-285
