The bright GRB 050408 was localized by HETE-II near local midnight , enabling an impressive ground-based followup effort as well as space-based followup from Swift .
The Swift data from the X-Ray Telescope ( XRT ) and our own optical photometry and spectrum of the afterglow provide the cornerstone for our analysis .
Under the traditional assumption that the visible waveband was above the peak synchrotron frequency and below the cooling frequency , the optical photometry from 0.03 to 5.03 days show an afterglow decay corresponding to an electron energy index of p _ { lc } = 2.05 \pm 0.04 , without a jet break as suggested by others .
A break is seen in the X-ray data at early times ( at \sim 12600 sec after the GRB ) .
The spectral slope of the optical spectrum is consistent with p _ { lc } assuming a host-galaxy extinction of A _ { V } = 1.18 mag .
The optical-NIR broadband spectrum is also consistent with p = 2.05 , but prefers A _ { V } = 0.57 mag .
The X-ray afterglow shows a break at 1.26 \times 10 ^ { 4 } sec , which may be the result of a refreshed shock .
This burst stands out in that the optical and X-ray data suggest a large H i column density of N _ { HI } \approx 10 ^ { 22 } { cm ^ { -2 } } ; it is very likely a damped Lyman \alpha system and so the faintness of the host galaxy ( M _ { V } > -18 mag ) is noteworthy .
Moreover , we detect extraordinarily strong Ti ii absorption lines with a column density through the GRB host that exceeds the largest values observed for the Milky Way by an order of magnitude .
Furthermore , the Ti ii equivalent width is in the top 1 % of Mg ii absorption-selected QSOs .
This suggests that the large-scale environment of GRB 050408 has significantly lower Ti depletion than the Milky Way and a large velocity width ( \delta v > 200 km s ^ { -1 } ) .