GCN Circular 4593
J. X. Prochaska (UCO-Lick/UCSC), R. Foley (UCB), H. Tran (Keck), J. S. Bloom (UCB), H.-W. Chen (MIT), report on behalf of the GRAASP collaboration: "We have obtained Keck/LRIS spectra of the afterglow of GRB 060124 starting at UT Jan 25 07:15 in polarimetry mode under poor observing conditions. We confirm the absorption features at ~5105A reported by Mirabal et al. (GCN 4591) and rule out MgII on the basis of their separation. Instead, we identify these features as CIV corresponding to z=2.296 and we note a weak absorption feature consistent with this redshift corresponding to AlII 1670. We also identify an absorption line at ~4000Ang consistent with Lya absorption and indicating log N(HI) < 20.5. Although we may also detect a weak feature consistent with SiII 1526 at 5030Ang, this afterglow spectrum is notable for exhibiting very weak low-ion features (e.g. non-detections of FeII 1608, OI 1302, CII 1334) and relatively low HI column density. In this respect the spectrum is similar to the afterglows of GRB 050908 and GRB 021004. Finally, we note a strong absorption feature at ~4840Ang which could be MgII at z=0.73. We thank the Keck Observatory for acquiring these observations during Director's discretionary time. The data will be made publically available at www.graasp.org" This message may be cited.