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 different epochs, a constant source was detected with an average flux density of 3.74 ± 0.53 mJy at 350 GHz and 1.05 ± 0.22 mJy at 250 GHz, giving a spectral index α = 3.78 ± 0.25 (where F ∝ ν^α). 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/near-IR properties of the host galaxy of GRB 010222 suggest that it is a blue sub-L* galaxy, similar to other GRB host galaxies. This contrasts with the enormous far-infrared luminosity of this galaxy based on our submillimeter detection (L_(Bol) ≈ 4 ×10^(12) L☉). We suggest that this GRB host galaxy has a very high star formation rate, SFR ≈ 600 M☉ yr^(-1), most of which is unseen at optical wavelengths.

Files

Additional details