GCN Circular 14286
Subject
GRB 130131B: host detection and redshift
Date
2013-03-11T14:20:28Z (11 years ago)
From
Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst <malesani@dark-cosmology.dk>
Johan P. U. Fynbo, Dong Xu, Daniele Malesani, Thomas Kruehler
(DARK/NBI), Dan A. Perley (Caltech), Valerio D'Elia (ASDC, INAF), report
on behalf of the X-shooter GTO GRB collaboration:
We observed the field of GRB 130131B (Siegel et al., GCN 14159) using
the Keck-I telescope equipped with the LRIS instrument. Observations
were carried out on 2013 February 10 (9.62 days after the burst),
simultaneously in the g and I bands, for a total exposure time of 750
and 720 s, respectively.
A source with g = 25.7 (AB) and I = 24.9 (Vega) is detected inside the
enhanced XRT error circle (which has a radius of 1.8"; Goad et al., GCN
14165), at coordinates:
R.A.(J2000) = 11:35:49.31
Dec.(J2000) = +15:02:18.0
We consider this object to be the likely host galaxy of GRB 130131B.
A spectrum of this source was taken on 2013 March 9 with the ESO VLT
equipped with the X-shooter spectrograph, covering the wavelength range
3000-20000 AA. The exposure time was 8x900 s. In the NIR arm, we detect
three emission lines, interpreted as [O III] (4960, 5007) and [O II]
(3727), all at a common redshift z = 2.539. In the UVB arm, the host
continuum is detected down to ~4400 AA, which corresponds to the onset
of the Lyman alpha forest at the proposed redshift.
We acknowledge excellent support from the observing staff at Mauna Kea
and Paranal, in particular Emanuela Pompei, Claudio Melo, and Thomas
Rivinius.