SCUBA sub-millimeter observations of gamma-ray bursters

II. GRB 991208, 991216, 000301C, 000630, 000911, 000926

¹ Department of Physics and Astronomy, Rice University, MS-108, 6100 South Main, Houston, TX 77005-1892, USA
² Joint Astronomy Centre, 660 N. Aohoku Place, Hilo, HI 96720, USA
³ Department of Physics and Astronomy, SUNY, Stony Brook, NY 11794-3800, USA
⁴ Department of Physical Sciences, University of Hertfordshire, College Lane, Hatfield, Herts AL10 9AB, UK
⁵ Astronomical Institute "Anton Pannekoek" , University of Amsterdam and Center for High-Energy Astrophysics, Kruislaan 403, 1098 SJ Amsterdam, The Netherlands
⁶ NASA Marshall Space Flight Center, SD-50, NSSTC, 320 Sparkman Drive, Huntsville, AL 35805, USA
⁷ Universities Space Research Association

Corresponding author: I. A. Smith, ian@spacsun.rice.edu

Received: 31 January 2001
Accepted: 2 October 2001

Abstract

We discuss our ongoing program of Target of Opportunity sub-millimeter observations of gamma-ray bursts (GRBs) using the Sub-millimetre Common-User Bolometer Array (SCUBA) on the James Clerk Maxwell Telescope (JCMT). Sub-millimeter observations of the early afterglows are of interest because this is where the emission peaks in some bursts in the days to weeks following the burst. Of increasing interest is to look for underlying quiescent sub-millimeter sources that may be dusty star-forming host galaxies. In this paper, we present observations of GRB 991208, 991216, 000301C, 000630, 000911, and 000926. For all these bursts, any sub-millimeter emission is consistent with coming from the afterglow. This means that we did not conclusively detect quiescent sub-millimeter counterparts to any of the bursts that were studied from 1997 through 2000. The inferred star formation rates () are typically ≲ . If GRBs are due to the explosions of high-mass stars, this may indicate that the relatively small population of extremely luminous dusty galaxies does not dominate the total star formation in the universe at early epochs. Instead, the GRBs may be predominantly tracing slightly lower luminosity galaxies. The optical faintness of some host galaxies is unlikely to be explained as due to dust absorption in the host.