Detection of the X-ray Transient EP241212a by the Einstein Probe
ATel #16943; R.-Z. Li (YNAO, CAS), X.-Y. Zhou (PRIC), D.-F. Hu (PMO, CAS), S.-X. Wen, H.-W. Pan (NAO, CAS) report on behalf of the Einstein Probe team:
on 13 Dec 2024; 09:34 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Yuan Liu (liuyuan@bao.ac.cn)
Subjects: X-ray, Transient
We report on the detection of an X-ray transient by the Einstein Probe (EP), designated as EP241212a. The source was first detected by the Wide-field X-ray Telescope (WXT) on board EP in a single pointing observation (with an exposure time of 6.8 ks) at 2024-12-12T11:21:52 (UTC). The position of the transient is R.A. = 153.817 deg, Dec. = 60.068 deg, with an uncertainty of 2.5 arcmin. A faint X-ray source, 1WGA J1015.3+6004/Gaia DR3 1048515045825830144 (R.A. = 153.83607, Dec. = +60.07485), is located at a distance of approximately 107 pc and about 42 arcsec from the position detected by WXT. Therefore, the possibility of a stellar flare cannot be ruled out.
No significant variability in the light curve was observed throughout the observation. The WXT spectrum of the observation can be fitted by an absorbed power law with a photon index of 2.7+/-1.0, with the NH of (3.8+/-2.7) e21 cm^-2. The derived absorbed flux in 0.5-4 keV is (1.9+/-0.2) e-11 ergs/s/cm^2.
A Swift-XRT ToO proposal was submitted to observe the transient. Multi-wavelength follow-up observaitons 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.
