TITLE: GCN CIRCULAR NUMBER: 15773 SUBJECT: GRB 140129A: P200 spectroscopy DATE: 14/01/30 01:58:46 GMT FROM: Daniel Perley at Caltech D. A. Perley (Caltech), M. Rafelski, D. Masters (IPAC), and J. X. Prochaska (UCO/Lick) report: We obtained spectroscopy of the optical afterglow of GRB 140129A (Melandri et al., GCN 15760) with the Double Spectrograph at the 5m Palomar Hale telescope beginning at 04:56:25.2 UT, approximately 1.5 hours after the GRB trigger. Based on our P60 imaging, the GRB afterglow was r~20 mag at this point and the S/N of the spectrum is low, although the trace is clearly detected in each of three 600s exposures. The spectral range covers from the atmospheric cutoff to 8700 Angstroms. The spectrum is featureless, showing no significant absorption lines over our spectral range (although the EW sensitivity limit is poor). The absence of a DLA feature suggests a redshift of z<1.8 (more conservatively, the lack of IGM absorption down to the atmospheric cutoff indicates z<2.1).