TITLE:   GCN CIRCULAR
NUMBER:  36085
SUBJECT: GRB 240414A : OHP/T193 redshift determination
DATE:    24/04/14 04:55:18 GMT
FROM:    Christophe Adami at LAM <christophe.adami@lam.fr>

C. Adami,  O. Ilbert, S. de la Torre (LAM/Pytheas/AMU), A. de Ugarte Postigo (OCA/LAM), B. Schneider (MIT), E. Le Floc’h (CEA Paris-Saclay), report on behalf  of a larger collaboration:

We observed the optical counterpart of GRB 240414A (Caputo et al., GCN 36083, Schneider et al., GCN 36084)
in spectroscopy with the MISTRAL instrument in blue mode using the T193cm telescope at Observatoire de
Haute-Provence (France).

We detect the optical GRB afterglow at RA = 12:19:08.08 and DEC = +56:44:28.8 (J2000).

Our spectra cover the wavelength range 4200-8000 AA and consist of 3 exposures of 900 seconds each.
Observations started at 03:17:09 UT on April 14, 2024 (~57 min after the X-ray trigger). We detect a strong
continuum with absorption features which we identify as AlII, AlIII, FeII, MnII and MgII at a common redshift
of z=1.833 that we interpret as the redshift of GRB 240414A.

Our photometric data reduction continue with g' band observations.

We acknowledge the excellent support from Observatoire de Haute-Provence and in particular Jean-Pierre Troncin
for the MISTRAL observations.