[vsnet-grb-info 22751] GRB 190613A: SEDM Observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  24850
SUBJECT: GRB 190613A: SEDM Observations
DATE:    19/06/19 14:01:11 GMT
FROM:    Virginia Cunningham at U of MD  <vcunning at 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.