GRB 210306A: Early Spectroscopy of the Optical Afterglow
Abstract
Observations of the optical counterpart of GRB 210306A using the B&C Spectrograph and the University of Arizona, Steward Observatory 2.3m Bok Telescope located on Kitt Peak, Arizona began at 07:07:50 on March 6, 2021 UTC and ended at 08:23:13 UT. Three, 1500 s exposures were obtained centered at 3.384, 3.859, and 4.279 hours after the Swift/BAT detection of the burst (D'Elia et al.; GCN Circ. 29597). Comparison with a spectrophotometric standard star observed immediately after the optical afterglow observations suggest that the counterpart was at an approximate V magnitude of 19.18, 19.33, and 19.46 for the three exposures, respectively. All spectra show a featureless blue continuum from 350-760nm. A fit to the least noisy portion (450-750nm) of the scaled median spectrum from the three observations yields a slope of about -1.25 in log(F_lambda) vs. log(wavelength). No corrections for Galactic extinction and reddening have been made.
- Publication:
-
GRB Coordinates Network
- Pub Date:
- March 2021
- Bibcode:
- 2021GCN.29638....1S