GCN Circular 20584
Subject
GRB 170202A: Redshift from OSIRIS/GTC
Date
2017-02-03T00:22:15Z (7 years ago)
From
Antonio de Ugarte Postigo at IAA-CSIC <deugarte@iaa.es>
A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), L. Izzo (IAA-CSIC),
C. Thoene (IAA-CSIC), D.A. Kann (IAA-CSIC, TLS), P. Pessev
(GRANTECAN, IAC, ULL), A. Perez (GRANTECAN) report on
behalf of a larger collaboration:
We observed the afterglow of GRB 170202A (Racusin et al.
GCN 20575) using OSIRIS at the 10.4m GTC telescope at the
Roque de los Muchachos observatory (La Palma, Spain). The
observation started at 23:22 UT (4.91 hr after the burst) and
included observations with grisms R1000B and R1000R covering
the ranges 3700 - 7800 AA and 5100 - 9300 AA respectively.
The blue spectra shows a strong signal with multiple features being
especially significant Lyman-alpha (both in absorption and emission),
the full Ly-forest, NV, SII, SiII, SiII*, OI, CII, SiIV, CIV and AlII at a
common redshift of 3.645, which we identify as the redshift of the
GRB.