GCN Circular 38080
Subject
GRB 241010A: host galaxy redshift z = 0.977
Event
Date
2024-11-05T11:52:14Z (a year ago)
From
Daniele B. Malesani at IMAPP / Radboud University <d.malesani@astro.ru.nl>
Via
Web form
D. B. Malesani (DAWN/NBI and Radboud Univ.), A. Cabrera-Lavers (GTC), J. F. Agui Fernandez (CAHA), A. de Ugarte Postigo (LAM/OCA, CNRS), C. C. Thoene (ASU-CAS, AbAO), J. Rastinejad (Northwestern), B. P. Gompertz (Birmingham), A. J. Levan (Radboud Univ. and Warwick Univ.), W. Fong (Northwestern), N. R. Tanvir (U. Leicester), J. P. U. Fynbo (DAWN/NBI), L. Izzo (INAF-OACn & DARK/NBI), A. Martin-Carrillo (UCD), G. Lombardi (GTC), S. Geier (GTC) report:
At the location of the optical afterglow of GRB 241010A (Dichiara et al., GCN 37755), an object is visible in the Legacy survey, first noticed by Jiang et al. (GCN 37771). This is most likely the GRB host galaxy.
On 2024 November 2, once the field became visible to ground-based observatories, we secured spectroscopic observations of the host galaxy using the Gran Telescopio Canarias (GTC) equipped with the OSIRIS+ instrument. Three spectra of 900 s each were obtained, using the R1000R grism, which covers the wavelength range 5150-10200 AA.
On top of clear continuum, a multitude of emission lines are visible, which we interpret as due to [O II], [Ne III] 3869, Hdelta, Hgamma, Hbeta, [O III] 4958 and [O III] 5006, all at a common redshift z = 0.977, which we suggest to be the redshift of GRB 241010A. This value is consistent with the photometric estimate from the Legacy survey (z_ph = 0.87 +- 0.11; Zhou et al. 2021, MNRAS, 501, 3309).