LOTIS, Super-LOTIS, Sloan Digital Sky Survey, and Tautenburg Observations of GRB 010921
Cline, T.; Hurley, K.; Brinkmann, J.; Hartmann, D. H.; Klose, S.; Stecklum, B.; Gehrels, N.; Schneider, D. P.; Hennessy, G. S.; Neilsen, E. H.; Tucker, D. L.; Ivezić, Željko; Barthelmy, S. D.; Kent, S.; Henden, A.; Kleinman, S. J.; Nitta, A.; Lamb, D. Q.; York, D.; Park, H. S.; Williams, G. G.; Lee, B. C.; Adelman, J.; Briggs, J. W.; Chen, B.; Csabai, I.; Harvanek, M.; Krzesinski, J.; Lindsay, K.; Long, D.; Nemiroff, R.; Newberg, H. J.; Newman, P. R.; Perez, D.; Periera, W.; Snedden, S. A.; Stoughton, C.; Vanden Berk, D. E.; Ziock, K.
United States, Germany, Spain, Hungary, Poland
Abstract
We present multi-instrument optical observations of the High Energy Transient Explorer (HETE-2) and Interplanetary Network error box of GRB 010921. This event was the first gamma-ray burst (GRB) partly localized by HETE-2 that has resulted in the detection of an optical afterglow. In this Letter, we report the earliest known observations of the GRB 010921 field, taken with the 0.11 m Livermore Optical Transient Imaging System (LOTIS) telescope, and the earliest known detection of the GRB 010921 optical afterglow, using the 0.5 m Sloan Digital Sky Survey Photometric Telescope (SDSS PT). Observations with the LOTIS telescope began during a routine sky patrol 52 minutes after the burst. Observations were made with the SDSS PT, the 0.6 m Super-LOTIS telescope, and the 1.34 m Tautenburg Schmidt telescope 21.3, 21.8, and 37.5 hr, respectively, after the GRB. In addition, the host galaxy was observed with the US Naval Observatory Flagstaff Station 1.0 m telescope 56 days after the burst. We find that at later times (t>1 day after the burst), the optical afterglow exhibited a power-law decline with a slope of α=1.75+/-0.28. However, our earliest observations show that this power-law decline cannot have extended to early times (t<0.035 days).