1997/10/31 by M. R. Garcia, P. J. Callanan, D. Moraru +9
Engineering · Physics and Astronomy · #Astronomical Observations and Instrumentation #Astronomy #Astrophysics #COSMIC cancer database #Exponent #Gamma-ray burst #Gamma-ray bursts and supernovae #Light curve #Magnitude (astronomy) #Observatory #Philosophy #Physics #Power law #Stellar, planetary, and galactic studies #Telescope #astro-ph
paper · pdf · doi:10.1086/311403
replacement, now accepted by ApJ(lett), 8 pages, 1 figure
arxiv created 1998/04/27 · openalex publication_date 1998/06/20 · arxiv updated 2009/12/01 · openalex created_date 2020/11/23 · openalex updated_date 2026/08/05
We report on R C - and K -band observations of the optical counterpart to GRB 970508 with the Fred Lawrence Whipple Observatory (FLWO) 1.2 m telescope. Eleven R C -band observations were obtained on 1997 May 12, and three on May 14. The counterpart clearly faded between the two nights. On May 12 there was no evidence for variability (<9%) on 10-70 minute timescales based on 11 R c -band observations. On May 19 a 1 hr observation set a limit on the K magnitude of K >18.6. Comparison of these data points with those obtained by other authors shows that the decay of the optical counterpart can be well fitted by a power law of the form f ~ t -α , where α=1.22±0.03 with occasional fluctuations superposed. We note that the decay of the optical counterpart to another burst, GRB 970228, can also be well fitted with a power law with exponent α=1.0 + 0.2 −0.5 with occasional fluctuations superposed. These two decay light curves are remarkably similar in form to that predicted by cosmic-fireball models.