MAXI/GSC detection of a possible intermediate-duration burst from the direction of Terzan 1
ATel #17961; M. Serino (AGU), W. Iwakiri (Chiba U.), H. Negoro, M. Nakajima, K. Saito, T. Yokoyama, M. Wada (Nihon U.), T. Mihara, T. Tamagawa, N. Kawai, M. Matsuoka (RIKEN), T. Sakamoto, S. Sugita, Y. Kawakubo, H. Hiramatsu, A. Yoshida (AGU), Y. Tsuboi, Y. Ishihara, H. Ogaki (Chuo U.), M. Shidatsu, C. Kang, M. Uenishi, T. Usuki, S. Yatsuzuka, H. Aoe (Ehime U.), I. Takahashi, Y. Yatsu (Science Tokyo), S. Nakahira, S. Ueno, H. Tomida, M. Kurihara (JAXA), Y. Ueda, K. Fujiwara, S. Kobayashi (Kyoto U.), M. Yamauchi, M. Nishio, C. Hiraizumi (Miyazaki U.), K. Yamaoka (Nagoya U.), M. Sugizaki (Kanazawa U.), T. Kawamuro (Osaka U.), S. Yamada (Tohoku U), S. Ogawa (TUS)
on 12 Aug 2026; 12:34 UT
Credential Certification: Motoko Suzuki (motoko@crab.riken.jp)
Subjects: X-ray, Binary, Neutron Star
The MAXI/GSC nova alert system triggered on a bright transient event at 13:47:42 UT on August 2 2026
from the position consistent with a globular cluster Terzan 1.
No significant excess at the previous scan.
The spectra of the detection is fitted by an absorbed blackbody model with a temperature kT = 1.5 (+0.1, -0.1) keV,
and the hydrogen column density of 2.9 (+1.5, -1.3) × 1022 cm-2.
Assuming a distance of Terzan 1 (6.7 kpc), the unabsorbed bolometric luminosity was about 4.4 (+0.5 -0.4) × 1038.
The flux remained almost constant throughout a single MAXI/GSC scan, lasting approximately 40 s.
At the time of the next scan transit (15:20 UT), the flux had decreased to less than 2% of
that measured in the previous scan. Assuming an exponential decay, the e-folding decay time is
estimated to be < 0.4 hr. The sustained emission during the scan and the subsequent rapid decay
suggest that the event is a candidate intermediate-duration burst.
