Einstein Probe detects possible X-ray brightening of the Low-Mass X-ray Binary 4U 1246-58
ATel #17168; Y. L. Wang (NAO, CAS; ICE, CSIC-IEEC), H. Y. Liu (NAO, CAS), H. L. Peng (NJNU), X. L. Chen(YNU), C. C. Jin (NAO, CAS) report on behalf of the Einstein Probe team:
on 5 May 2025; 16:59 UT
Credential Certification: Yilong Wang (wangyilong@nao.cas.cn)
We report the detection of possible X-ray brightening from the low-mass X-ray binary (LMXB) 4U 1246-58, by the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission. The source exhibited a gradual flux increase starting in late April 2025, reaching peak brightness during an observation at 2025-05-01 09:37:15 (UTC).
The WXT spectrum during the peak can be fitted by an absorbed power-law with a photon index of 2.3 (+0.5/-0.4) and a neutral hydrogen column density of 5.8 (+1.5/-1.4) x 10^21 cm^-2. The derived absorbed flux in 0.5-4 keV is 2.2 (+0.4/-0.2) e-10 erg/s/cm^2, which is roughly four times of the persistent flux level of ~ 5e-11 erg/s/cm^2.
Multi-wavelength follow-up observations are encouraged.
Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). EP is a mission of the Chinese Academy of Sciences in collaboration with ESA, MPE and CNES.
