GRB 010222: A Burst Within a Starburst

Abstract

We present millimeter and submillimeter wavelength observations and near-infrared K-band imaging toward the bright gamma-ray burst GRB 010222. Over seven epochs the flux density of the source was constant with an average flux density 3.74+/-0.53 mJy at 350 GHz and 1.05+/-0.22 mJy at 250 GHz, giving a spectral index alpha=3.78+/-0.25. We rule out the possibility that this emission originated from the burst or its afterglow and we conclude that it is due to a dusty, high redshift starburst galaxy (SMM J14522+4301). We argue that the host galaxy of GRB 010222 is the most plausible counterpart of SMM J14522+4301, based in part on the centimeter detection of the host at the expected level. The optical/NIR properties of the host galaxy of GRB 010222 suggest that it is a blue, sub-L_*, similar to other GRB host galaxies. This contrasts with the enormous far-infrared luminosity of this galaxy based on our submillimeter detection (L_Bol~4X10^{12} L_odot). We suggest that this GRB host galaxy has a very high star formation rate, SFR 600 M_\odot/yr, most of which is unseen at optical wavelengths.