Fast X-ray Transients (FXTs) represent a new class of highly luminous transients in soft X-rays (∼0.3-10 keV) associated with violent astrophysical processes. They manifest as short, singular flashes of X-ray photons with durations lasting from minutes to hours. Their origin remains unclear, and they have been associated with various progenitor mechanisms. The newly launched X-ray survey, Einstein-Probe (EP), is revolutionising this field by enabling the discovery and immediate follow-up of FXTs. Here we present the multiwavelength observations of EP-discovered FXT EP241107a and the discovery of its radio counterpart. Comparison of the optical and radio observations of EP241107a and its host properties with other extragalactic transients suggests a gamma-ray burst (GRB) origin. Through our afterglow modelling, we infer the GRB jet properties for EP241107a, yielding a jet of the isotropic-equivalent kinetic energy EK,iso∼1051 erg, with a half opening angle θc≈15∘, viewed at an angle of θobs~≈9∘. We also evaluate EP241107a in the landscape of both EP-discovered FXTs as well as the FXTs discovered from Chandra, XMM-Newton, and Swift-XRT.
@article{arxiv.2511.02562,
title = {Characterising EP241107a: Multiwavelength Observations of an Einstein Probe-detected Fast X-ray Transient},
author = {D. Eappachen and A. Balasubramanian and Vishwajeet Swain and G. C. Anupama and D. K. Sahu and V. Bhalerao and T. Ahumada and I. Andreoni and Sudhanshu Barway and J. Carney and J. Freeburn and M. M. Kasliwal and Tanishk Mohan and A. C. Rodriguez and G. Waratkar},
journal= {arXiv preprint arXiv:2511.02562},
year = {2025}
}