GRB 030329

GRB 030329 was one of three gamma-ray bursts detected on 29 March 2003. The other two were labeled GRB 030329a[1] and GRB 030329b.[2] GRB 030329 was detected by multiple instruments onboard HETE at 11:37 UTC and lasted approximately 25 seconds.[3] The burst's optical afterglow was first observed from Siding Spring Observatory less than two hours after the burst had been detected.[4] The X-ray afterglow was first detected by RXTE approximately five hours after the burst.[5] The radio afterglow was first detected by the Very Large Array and, at the time of its discovery, was the brightest radio afterglow ever observed.[6] The burst was located at a sky position of R.A. =  10^h 44^m 49.95957^s, Dec. = +21° 31′ 17.4375″ and had a redshift of z = 0.1685, corresponding to a distance of 587 Mpc.[7]

GRB 030329's proximity to Earth enabled its afterglow to be studied in great detail. A spectrum taken of the burst's optical afterglow on 6 April 2003 showed peaks at approximately 570 nm and 470 nm. This spectrum was reproduced by combining a power-law distribution with the spectrum from SN 1998bw.[8] These supernova-like features continued to develop in the weeks after the initial burst.[9] Optical observations taken at Kitt Peak National Observatory on indicated that the burst's optical afterglow was brighter than a power-law decay would have predicted, a deviation that could have been explained by additional light from a supernova.[10] On 10 April 2003, NASA announced that GRB 030329 had provided the definitive link between gamma-ray bursts and supernovae.[11] The supernova was later referred to as SN 2003dh.[12]