The Host Galaxy of GRB 971214

Abstract

GRB 971214 is the third gamma ray burst for which an optical afterglow has been detected. I show that the spectrum of this afterglow (optical and X-ray) is inconsistent with the relativistic blast-wave model unless a significant source of extinction is introduced. Assuming that a single absorber exists at redshift z, I find that its V-band absorption magnitude at this redshift is A_V(z) = 1.00^{+1.55}_{-0.21} mag where z = 1.89^{+0.27}_{-0.69}. Although this redshift is only bound from below marginally, it is strongly bound from above: z < 2.50 at the 3 sigma confidence level. This range of values for the V-band absorption magnitude is too high to be consistent with absorption by either intergalactic gas or the halo of a galaxy, which implies that GRB 971214 lies either within or behind a galactic disk. Since chance alignments of galactic disks are unlikely, this absorber is probably the host galaxy of GRB 971214.