A JHK' SURVEY OF THE ERROR BOX OF THE GAMMA-RAY BURST 790418

摘要

We performed a deep JHK' survey of the 2.9 arcmin~2 positional error box of the gamma-ray burst (GRB) 790418. At limiting magnitudes of J～21, H～20, and K～19, we find about 20 objects within the box, galaxies as well as very red stars. A relatively bright galactic nucleus (K = 16.3), presumably the bulge of a spiral galaxy, is located about 5″ outside the 3 σ box given in Vrba, Hartmann, & Jennings, with its halo region possibly extending inside the box. Although this seems to match well into the framework of the cosmological Model of GRBs, the assumption that this galaxy is physically related to GRB 790418 is not strongly supported by simple statistical arguments. No potential Galactic halo burst source could be selected from our data.