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GCN Circular 40548

Subject

EP J1350.0-8622: Einstein Probe detection of an X-ray transient candidate

Date

2025-05-26T15:19:07Z (11 days ago)

From

EP Team at NAOC/CAS <ep_ta@bao.ac.cn>

Via

Web form

M. J. Liu, D. H. Zhao (NAO, CAS), Y. Wang(PMO, CAS), W. D. Zhang (NAO, CAS) on behalf of the Einstein Probe (EP) team:

We report on the detection of an X-ray transient candidate at 2025-05-25T23:18:23 (UTC) by the Wide-field X-ray Telescope (WXT) on board Einstein Probe (EP), which we designated EP J1350.0-8622. This source was discovered through on-ground analysis of WXT telemetry data. The WXT position of the source is R.A. = 207.494 deg, DEC = -86.373 deg (J2000) with an uncertainty of 2.6 arcmin in radius (90% C.L. statistical and systematic). The derived unabsorbed 0.5-4 keV flux by an absorbed power-law model is 6.8(+9.6/-6.8) x 10^-12 erg/cm^2/s with the column density fixed at the Galactic value of 8.2 x 10^20 cm^-2 and photon index fixed at 2.

Within the WXT error circle, an X-ray source 1eRASS J135031.1-862323 was detected by eROSITA with a flux of 4.9 x 10^-14 erg/cm2/s (0.6-2.3 keV). A Gaia source Gaia DR3 5766213157904565376, likely a quasar, is 8.155 arcsec away from the eROSITA source.

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).