The startling discovery of Prochter et al. (2006) that the frequency of very strong (W_r(2796)>1 A) MgII absorbers along gamma-ray burst (GRB) lines of sight ([dN/dz]_{GRB} = 0.90) is more than three times the frequency along quasar lines of sight ([dN/dz]_{QSO} = 0.24), over similar redshift ranges, has yet to be understood. We reconsider the possibility that the excess of very strong MgII absorbers toward GRBs is intrinsic either to the GRBs themselves or to their immediate environment, and associated with bulk outflows with velocities as large as v_{max} ~ 0.3c. In order to examine this hypothesis, we accumulate a sample of 27 W_r(2796) > 1 A absorption systems found toward 81 quasars, and compare their properties to those of 9 W_r(2796)>1 A absorption systems found toward 6 GRBs; all systems have been observed at high spectral resolution (R = 45,000) using the Ultraviolet and Visual Echelle Spectrograph on the Very Large Telescope. We make multiple comparisons of the absorber properties across the two populations, testing for differences in metallicity, ionization state, abundance patterns, dust abundance, kinematics, and phase structure. We find no significant differences between the two absorber populations using any of these metrics, implying that, if the excess absorbers toward GRB lines of sight are indeed intrinsic, they must be produced in a process which has strong similarities to the processes yielding strong MgII systems in association with intervening galaxies. Although this may seem a priori unlikely, given the high outflow velocities required for any intrinsic model, we note that the same conclusion was reached, recently, with respect to the narrow absorption line systems seen in some quasars.

The startling result of [1] that the number of very strong MgII absorbers (with equivalent width of the blue component bigger than 1 angstrom) along gamma-ray burst (GRB) sightlines is nearly four times larger ([dN/dz](GRB) = 0.90) than that along quasar sightlines ([dN/dz](QSO) = 0.24) has yet to be understood. We reconsider the possibility that the excess of verb strong MgII absorbers toward GRBs is due to an origin intrinsic to the GRBs testing for possible differences in some properties (line profile, dust abundance and kinematics) of very strong MgII absorbers found toward GRBs versus those found toward quasars. With a variety of comparisons of equivalent widths of numerous transitions and of the kinematics of the MgII profiles, we find no significant differences between these samples. This implies that if the excess of very strong MgII absorbers toward GRBs is caused by a phenomena in the local GRB environment, that the process involved must have some similarities to that which produces very strong MgII absorbers toward GRB. Although we might be inclined to refute an intrinsic origin of the GRB absorbers, we note that many narrow absorption line systems intrinsic to quasars are quite difficult to distinguish from intervening quasar absorbers despite an obviously different physical origin in accretion disk winds.