GRB 000131 was detected on 31 January 2000 at 14:59UTCbyUlysses,KONUS,NEAR Shoemaker,andBATSE.It lasted approximately 90 seconds.[1]The initial position, derived from the observations of all the aforementioned spacecraft, was estimated at aright ascensionof6h13m32.72sand adeclinationof −51° 55′ 36.77″.[2]On 4 February 2000, optical observations of the region were made by telescopes atParanal ObservatoryandLa Silla ObservatoryinChilewhich revealed the burst's optical afterglow.[3]
GRB 000131 had aredshiftof approximately z = 4.5.[4]This corresponds to a distance of about 11 billionlight years,making it the most distant gamma-ray burst that had ever been recorded up to that date.[5]This distance record was broken byGRB 050904,which had a redshift of z = 6.29.[6][7]
GRB 000131 was the first gamma-ray burst to have its optical afterglow detected by an 8-meter telescope. At the time of its discovery, GRB 000131 was the most distant burst ever detected. However, it was not the most energetic: assumingisotropicemission, the total energy output of the burst was approximately 1054ergs,placing it in second behindGRB 990123.Furthermore, the gamma-ray data also suggested that the burst was beamed rather than isotropic, a characteristic which would further decrease the total energy output. This demonstrated the importance of the use of optical telescopes in the studies of gamma-ray bursts.[8]
