LEIA detected a bright outburst from LMC X-4
ATel #15871; D. Y. Li, H. Sun, H. W. Pan, Z. X. Ling, Y. Liu, C. Zhang, H. Q. Cheng, C. Z. Cui, D. W. Fan, H. B. Hu, J. W. Hu, M. H. Huang, C. C. Jin, J. Q. Li, H. Y. Liu, M. J Liu, W. X. Wang, Y. L. Wang, Q. Y. Wu, X. P. Xu, Y. F. Xu, H. N Yang, M. Zhang, W. D. Zhang, D. H. Zhao and W. Yuan (NAOC, CAS), on behalf of the LEIA and Einstein Probe team
on 22 Jan 2023; 15:13 UT
Distributed as an Instant Email Notice Novae
Credential Certification: Yuan Liu (liuyuan@bao.ac.cn)
Subjects: X-ray, Binary, Nova
We report a bright outburst from the high mass X-ray binary LMC X-4 detected by LEIA (Lobster Eye Imager for Astronomy), also known as EP-WXT Pathfinder. The detected source position by LEIA is R.A. = 83.18 deg, DEC = -66.36 deg with an uncertainty of 2.2 arcmin (radius, 90% C.L. statistical and systematic), which is 55 arcsec away from LMC X-4.
LMC X-4 was covered twice by LEIA on January 20, 2023, and it brightened by more than an order of magnitude within 2 hours, with its 0.5 - 4.0 keV count rate increasing from 0.067 to 0.680 counts per second. During the outburst phase, the X-ray spectra can be fitted by a powerlaw with a photon index of 2.3 +/- 0.1 modified by Galactic absorption, and its 0.5 - 4.0 keV flux was ~1.6e-9 erg/s/cm2. This flux is comparable to the brightest fluxes of the outbursts of LMC X-4 as recorded by MAXI from August 2009 to January 2023.
Follow-up observations are encouraged to investigate this bright outburst from LMC X-4 in detail.
LEIA (Zhang et al. 2022, ApJL, 941, 2) 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.
