LEIA detection of the brightening of the Be X-ray binary RX J0520.5-6932
ATel #16571; Y. J. Zhang, C. Y. Wang (THU), Y. Liu, X. P. Xu, Z. X. Ling, C. Zhang, W. Chen, H. Q. Cheng, C. Z. Cui, D. W. Fan, H. B. Hu, J. W. Hu, M. H. Huang, C. C. Jin, D. Y. Li, T. Y. Lian, H. Y. Liu, M. J. Liu, Z. Z. Lv, X. Mao, H. W. Pan, X. Pan, H. Sun, W. X. Wang, Y. L. Wang, Q. Y. Wu, Y. F. Xu, H. N. Yang, M. Zhang, W. D. Zhang, W. J. Zhang, D. H. Zhao (NAOC, CAS), D. M. Li, Q. X. Li (BNU) and W. Yuan (NAOC, CAS) on behalf of the LEIA and Einstein Probe team
on 5 Apr 2024; 09:29 UT
Credential Certification: Yuan Liu (liuyuan@bao.ac.cn)
Subjects: X-ray, Binary, Neutron Star
We report on the brightening of the Be X-ray binary RX J0520.5-6932 detected by LEIA (Lobster Eye Imager for Astronomy). The brightening of the source was reported by Semena et al. (ATel #16562) and Sharma et al. (ATel #16569). The source was detected by six observations of LEIA from March 31 to April 2. The 0.5-4 keV spectrum can be fitted by an absorbed power law (N_H is fixed at 9e20 cm^-2, referred from Vasilopoulos et al. 2014). The results are listed as follows. All the errors are at the 90% confidence level.
Time | Unabsorbed flux | Photon Index | Exposure
| (10^-10 erg/s/cm2)| | (seconds)
2024-03-31T11:20:50 | 1.4+0.7/-0.6 | 1.2+0.9/-0.8 | 772
2024-03-31T12:54:26 | 0.9+0.6/-0.5 | 1.1+1.1/-1.2 | 722
2024-04-01T10:44:40 | 0.7+0.6/-0.4 | 1.5+/-1.2 | 729
2024-04-01T12:18:15 | 1.3+0.6/-0.5 | 0.7+/-0.7 | 732
2024-04-02T10:08:25 | 0.7+0.7/-0.3 | 1.6+1.1/-1.2 | 777
2024-04-02T11:41:59 | 1.0+/-0.4 | 1.5+/-0.7 | 745
LEIA will keep monitoring this source in the next several days.
As a pathfinder of the Einstein Probe mission, LEIA (Zhang et al. 2022, ApJL, 941, 2; Ling et al. 2023, RAA, 23, 095007) is a soft X-ray Lobster-eye imager (0.5 - 4.0 keV) with a FoV of 340 square degrees aboard the experimental satellite SATech-01 of the CAS, launched on July 27, 2022. The above result is preliminary and the final result will be published elsewhere.
