GCN Circular 39561
Subject
EP250302A: VLT/X-shooter tentative redshift
Date
2025-03-03T08:21:14Z (2 months ago)
From
Rosa L. Becerra at Tor Vergata, Roma <rosa.becerra@roma2.infn.it>
Via
Web form
Yu-Han Yang (U Rome), Eleonora Troja (U Rome), and Rosa Becerra (U Rome) report on behalf of the ERC BHianca team:
We observed the field of EP250302A (Dai et al., GCN 39556) with the X-Shooter spectrograph on the ESO VLT UT3 (Melipal). Observations began at T+13.6 hours and obtained a total of 4x600s spectra at an average airmass of about 1.9.
At the position of the optical counterpart (Zhu et al., GCN 39550; Busmann et al., GCN 39551; Leonini et al., GCN 39553; Wu et al., GCN 39555, Xin et al., GCN 39558) we detect a strong continuum in all three arms. Based on a preliminary analysis, we identify weak absorption lines consistent with Fe II and the Mg II doublet at redshift z=0.549.
Our observations suggest that the EP transient is not related to the nearby galaxy noted by Busmann et al., GCN 39551, but lies at higher redshift.
We thank the staff at the VLT, for the rapid execution of these observations.