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Einstein Probe detects possible X-ray brightening of the Low Mass X-ray Binary QX Nor

ATel #17013; Y. L. Wang, W. J. Zhang, W. X. Wang, Y. Liu (NAO, CAS) report on behalf of the Einstein Probe team:
on 3 Feb 2025; 07:30 UT
Credential Certification: Yuan Liu (liuyuan@bao.ac.cn)

Subjects: X-ray, Binary

We report on the detection of possible X-ray brightening of the Low Mass X-ray Binary QX Nor by the Einstein Probe (EP). The source was detected by the Wide-field X-ray Telescope (WXT) on board EP in a single pointing observation at 2025-02-02 05:25:34 (UTC), with an exposure time of 1.6 ks. The position of the source is R. A. = 243.162 deg, Dec. = -52.404 deg (J2000), with an uncertainty of 2.5 arcmin (radius, 90% C.L. statistical and systematic).

The WXT spectrum can be fitted by an absorbed power-law with a photon index of 1.3 (+0.5/-0.4) and a neutral hydrogen column density of 9.60 (+2.73/-2.35) x 10^21 cm^-2. The derived unabsorbed flux in 0.5-4 keV is 1.0 (+0.4/-0.2) e-9 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.