The Sub-Energetic GRB 031203 as a Cosmic Analogue to GRB 980425

Over the six years since the discovery of the {gamma}-ray burst GRB 980425, associated with the nearby (distance {approx}40 Mpc) supernova 1998bw, astronomers have fiercely debated the nature of this event. Relative to bursts located at cosmological distances, (redshift, z {approx} 1), GRB 980425 was under-luminous in {gamma}-rays by three orders of magnitude. Radio calorimetry showed the explosion was sub-energetic by a factor of 10. Here, the authors report observations of the radio and X-ray afterglow of the recent z = 0.105 GRB031203 and demonstrate that it too is sub-energetic. The result, when taken together with the low {gamma}-ray luminosity, suggest that GRB031203 is the first cosmic analogue to GRB980425. They find no evidence that this event was a highly collimated explosion viewed off-axis. Like GRB980425, GRB031203 appears to be an intrinsically sub-energetic {gamma}-burst. Such sub-energetic events have faint afterglows. Intensive follow-up of faint bursts with smooth {gamma}-ray light curves (common to both GRBs 031203 and 980425) may enable the authors to reveal their expected large population.