Abstract We report on follow-up observations of the recently discovered transient by the Einstein Probe, EP240709A, with the Neutron star Interior Composition Explorer. We also incorporated archival multiwavelength survey data from the Neil Gehrels Swift Observatory (X-ray), Gaia (optical), the Fermi Gamma-ray Space Telescope (gamma-ray), and the Wide-field Infrared Survey Explorer (infrared) to distinguish between blazars and stellar systems. We suggest that EP240709A is likely an active blazar.

Tentative Blazar Candidate EP240709A Associated with 4FGL J0031.5−5648: NICER and Archival Multiwavelength Observations