[vsnet-grb-info 21438] GRB 181213A: NOT optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  23537
SUBJECT: GRB 181213A: NOT optical observations
DATE:    18/12/14 10:01:41 GMT
FROM:    Kasper Elm Heintz at Univ. of Iceland and DAWN/NBI  <keh14 at hi.is>

K. E. Heintz (Univ. of Iceland), D. B. Malesani (DAWN/NBI/DTU and DARK/NBI), J. P. U. Fynbo (DAWN/NBI/DTU), A. de Ugarte Postigo (HETH/IAA-CSIC and DARK/NBI), L. Balaguer-Nuñez, J. Carbajo (Dept. FQA, Univ. de Barcelona), F. Galindo and C. Perez (NOT), report on behalf of a larger collaboration:

We observed the optical afterglow (Lipunov et al., GCN 23526; Hu et al., GCN 23527; Siegel et al., GCN 23529; Belkin et al., GCN 23530) of GRB 181213A (Evans et al., GCN 23525) with the 2.5-m Nordic Optical Telescope (NOT) equipped with AlFOSC.

Spectroscopy was secured: we obtained 4x900s exposures using grism 4 (with a wavelength coverage from 350 to 900 nm) starting at 23:27:14 UT on December 13 (i.e. 10.5 hr after trigger). The observations were obtained at a seeing around 1” but at an airmass > 3. From the acquisition image taken without filter we measure r = 20.6 +/- 0.2 AB mag, calibrated against SDSS r-band Pan-STARRS local photometry. The combined spectrum shows a low-S/N, mostly featureless continuum. Based on the detected continuum down to 415 nm we infer an upper limit on the redshift for the GRB of z < 2.4.