GCN Circular 24835
Subject
GRB 190613A: SEDM Observations
Date
2019-06-15T01:26:58Z (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 190613A (Ambrosi et al., GCN
24798) 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 04:18:22 UTC (8.75
minutes after the burst trigger time). We performed an 1800 s exposure over the
wavelength range 3800-9200 A. The continuum emission is well-fit by a power
law spectrum with index alpha = 0.56 (f_nu ~ nu^-alpha). We detect an
absorption line at an observed wavelength of ~ 4597 A. We tentatively identify
this line as due to Lyman alpha at z = 2.78 - however due to the lack of
corroborating features we consider this redshift tentative currently.
[GCN OPS NOTE(07sep19): Per author's request, in the last paragraph,
the "alpha = 0.56" was changed to "alpha = 1.4".]