TITLE: GCN CIRCULAR NUMBER: 17616 SUBJECT: GRB 150323A: Keck redshift DATE: 15/03/23 07:20:09 GMT FROM: Daniel Perley at Caltech D. A. Perley (Caltech) and S. B. Cenko (GSFC) report: Using the Low Resolution Imaging Spectrometer (LRIS) on the Keck I 10m telescope, we acquired a single 900s spectrum of the optical afterglow (Cenko et al., GCN 17612) of GRB 150323A (Amaral-Roger et al., GCN 17611) beginning at 06:11 UT, at the end of evening twilight. A number of absorption and emission lines are detected in the 1D spectrum, including e.g. Fe II (2344,2374,2383,2585,2599), Mg II (2796,2803), Mg I (2853), OII (3727), OIII (4959, 5007), and H-beta at a common redshift of z=0.593. We acknowledge S. Kulkarni for the observing time.