GCN Circular 24836
Subject
GRB 190613B: SEDM Observations
Date
2019-06-15T01:26:59Z (5 years ago)
From
Virginia Cunningham at U of MD <vcunning@astro.umd.edu>
V. Cunningham (U of Maryland), J. D. Neill (Caltech), S. B. Cenko
(NASA GSFC), and R. Walters (Caltech) report on behalf of the
SEDM team:
We observed the optical counterpart to GRB 190613B (D'Ai et al. GCN 24807)
with the Spectral Energy Distribution Machine (SEDM) on the 60 inch
telescope at Palomar Observatory. The SEDM is a low resolution (R ~ 100)
integral field unit spectrometer with a multi-band (ugri) rainbow camera imager
(see Blagorodnova et al. 2018, PASP, 130, 035003, and Rigault et al. 2019,
astro-ph/1902.08526).
The SEDM began observing the optical counterpart at 11:00:28 UTC (11.79
minutes after the burst trigger time). We performed an 1800 s exposure over
the wavelength range 3800-9200 A. We tentatively identify an absorption
feature at ~ 5385 A that is consistent with the Mg II 2796,2803 doublet at
z = 0.92. However, due to the relatively low significance of the feature and
the lack of corroborating lines, we cannot confirm this redshift currently.
The continuum emission is well-fit by a power law spectrum with index alpha = 1.8
(f_nu ~ nu^-alpha).
[GCN OPS NOTE(07sep19): Per author's request, In the last sentence,
the "alpha = 0.09" was changed to "alpha = 1.8".]