GCN Circular 43749
Subject
EP260214b: VLT/X-shooter spectroscopic redshift z = 1.208
Event
Date
2026-02-15T10:06:03Z (2 days ago)
From
Aishwarya L Thakur at INAF-IAPS, Rome <aishth@outlook.com>
Via
Web form
E. Le Floch (CEA/Irfu), J. An (NAOC), A. Saccardi (CEA/Irfu), A. L. Thakur (INAF-IAPS), D. Xu (NAOC), L. Cotter (UCD), D. Malesani (DAWN/NBI and Radboud), N. R. Tanvir (U. Leicester) report on behalf of the Stargate collaboration
We observed the optical counterpart (He et al. GCN 43745; Watson et al. GCN 43747) of EP260214b (Yang et al. GCN 43744) using the ESO/VLT UT3 (Melipal) equipped with the X-shooter spectrograph. Our spectra cover the wavelength range 3000-21000 Å and consist of 4 exposures of 600 s each. Observations started on 2026 February 15 at 06:24:46 UT (at 8.35 hr post-trigger).
In a preliminary reduction of the spectra, we detect continuum over the entire wavelength range. From the detection of multiple absorption lines, which we interpret as the Al II, Fe II, Mg II, we infer a redshift of z = 1.208. Additionally, at a consistent redshift (z = 1.207) we note the presence of several emission lines due to the [O II] doublet, Ne III, the [O III] doublet, and the Balmer lines from the GRB host galaxy.
We acknowledge the excellent support of the ESO observing staff in Paranal, in particular Celia Desgrange, Mar Carretero Castrillo, Diego Parraguez and Fuyan Bian. The analysis of this spectrum was carried out with the help of the zHunter tool (https://doi.org/10.5281/zenodo.15189495).