GCN Circular 37471
Subject
GRB 240912A: NOT optical spectroscopy
Event
Date
2024-09-12T09:45:30Z (10 months ago)
From
Dong Xu at NAOC/CAS <dxu@nao.cas.cn>
Via
Web form
J. An (NAOC), J.P.U. Fynbo (DAWN/NBI), S.Y. Fu, Z.P. Zhu, S.Q. Jiang, X. Liu, D. Xu (NAOC), Niilo Koivisto (NOT) report on behalf of a large collaboration:
We carried out the spectroscopy of the optical afterglow of GRB 240912A detected by Fermi/GBM (Fermi GBM team, GCN 37465) and Swift/BAT (Evans et al., GCN 37466), using the 2.56-m Nordic Optical Telescope (NOT) equipped with the ALFOSC camera, at a mean time of 2024-09-12T05:20:43, i.e., ~ 3.57 hrs after the Swift/BAT trigger, covering the wavelength range between ~ 3600 AA and ~ 8000 AA.
A total of 970 s spectral exposure was obtained. A continuum is throughout the whole spectral wavelength range, superimposed with three relatively strong absorption features, which can be interpreted as due to Fe II, Mg II and Mg I at a common redshift of z = 1.23, in agreement with the GTC measurement (de Ugarte Postigo et al., GCN 37469).