GCN Circular 16902
Subject
GRB141004A: Host galaxy redshift form GTC
Date
2014-10-07T10:39:48Z (10 years ago)
From
Antonio de Ugarte Postigo at IAA-CSIC <deugarte@iaa.es>
A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), C.C. Thoene (IAA-CSIC),
D. Malesani (DARK/NBI), S. Schulze (PUC, MAS), R. Sanchez-Ramirez
(UPV/EHU, IAA-CSIC), J. Gorosabel (UPV/EHU, IAA-CSIC),
C.A. Alvarez Iglesias (GTC, IAC), J. Molgo (GTC), and M. Rivero (GTC)
report on behalf of a larger collaboration:
We obtained spectroscopy of the optical counterpart of GRB 141004A
(D'Elia et al., GCN 16878, Mereghetti et al., GCN 16879) with OSIRIS at
the 10.4m GTC telescope on October 7, starting at 5:10 UT (~30 hr after
the GRB). In a preliminary reduction of a 2x600 s exposure with the
R1000R grism (covering from 5100 to 10000 A with a resolution of ~1000),
we detected several emission lines corresponding to [O II], H-beta and
[O III] at a common redshift of 0.573. This confirms that the tentative
emission line detection reported by Schulze et al. (GCN 16891) was
indeed real and that it corresponds to the [O II] 3727/3729 doublet.
We also detect emission from another galaxy within the slit at a similar
redshift of 0.571, with a projected distance of 22" to the East, which
corresponds to ~150 kpc at that redshift, probably belonging to the same
galaxy group. The nearby galaxy reported by D'Elia et al. (GCN 16881)
shows multiple emission features at a redshift of 0.279, and it is therefore
unrelated to the GRB.