MAXI/GSC detection of an X-ray outburst from the Be/X-ray binary pulsar IGR J06074+2205
ATel #17714; M. Nakajima, H. Negoro (Nihon U.), T. Mihara (RIKEN), K. Takagi, H. Nishio (Nihon U.), T. Tamagawa, N. Kawai, M. Matsuoka (RIKEN), T. Sakamoto, M. Serino, S. Sugita, Y. Kawakubo, H. Hiramatsu, Y. Kondo, D. Iijima, A. Yoshida (AGU), Y. Tsuboi, H. Sugai, N. Nagashima, Y. Ishihara (Chuo U.), M. Shidatsu, C. Kang, T. Nakamoto, M. Uenishi, T. Usuki, S. Yatsuzuka (Ehime U.), I. Takahashi, Y. Yatsu (Science Tokyo), S. Nakahira, S. Ueno, H. Tomida, S. Ogawa, 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.), W. Iwakiri (Chiba U.), T. Kawamuro (Osaka U.), S. Yamada (Tohoku U)
on 9 Mar 2026; 00:23 UT
Credential Certification: Motoki Nakajima (nakajima.motoki@nihon-u.ac.jp)
Subjects: X-ray, Binary, Neutron Star, Transient, Pulsar
Referred to by ATel #: 17716
The MAXI/GSC nova alert system triggered on X-ray brightening from the position consistent with that of the Be/X-ray binary pulsar IGR J06074+2205 on 2026 March 7 (MJD 61106). The current brightening began on March 2 (MJD 61101), and the latest daily averaged X-ray flux in the 4-10 keV band obtained from the MAXI on-demand system (https://maxi.riken.jp/mxondem) reached 0.030 ± 0.008 photons s-1 cm-2 (24 ± 6 mCrab) on March 7 (MJD 61106).
The previous outburst from this source was reported by Swift and NuSTAR observations on 2025 September and October (ATel #17424, #17458). Although MAXI/GSC did not detect the event on 2025 September, six outbursts (2022 March, 2022 June, 2023 December, 2024 March, 2024 May, 2024 August) have been firmly detected from this source since the start of MAXI operation in 2009.
Following our estimation of the outburst recurrent period of 80 ± 2 days (ATel #16351, #16394), we attempt to revise the outburst periodicity using the data obtained after 2023 August 26 (MJD 60182) with MAXI/GSC. We performed an epoch-folding analysis (efsearch in FTOOLS) for the 4-10 keV data, and obtained a new ephemeris:
Toutburst peak = MJD 59983.63 + n * (80.1 ± 0.6).
Follow-up observations are encouraged.
