Physical Sciences and Mathematics Commons^™

Grb 021004: A Possible Shell Nebula Around A Wolf‐Rayet Star Gamma‐Ray Burst Progenitor, N. Mirabal, J. P. Halpern, Ryan Chornock, Alexei V. Filippenko, D. M. Terndrup, E. Armstrong, J. Kemp, J. R. Thorstensen, M. Tavarez, C. Espaillat

Dartmouth Scholarship

The rapid localization of GRB 021004 by the HETE-2 satellite allowed nearly continuous monitoring of its early optical afterglow decay, as well as high-quality optical spectra that determined a redshift of z_{3 =} 2.328 for its host galaxy, an active starburst galaxy with strong Ly emission and several absorption lines. Spectral observations show multiple absorbers at z_3A = 2.323, z_3B= 2.317, and z_3C = 2.293 blueshifted by ~450, ~990, and ~3155 km s^-1, respectively, relative to the host galaxy Lyα emission. We argue that these correspond to a fragmented shell nebula that has …