GCN Circular 6032
Jason X. Prochaska (UCSC), Gijs Roelofs (Nijmegen), Joshua Bloom (UCB) and Danny Steeghs (CfA) report on behalf of GRAASP: "We observed the afterglow of GRB 070125 with the LRIS dual spectrometer for 600s total starting at UT 05:44 under variable conditions. Our high signal-to-noise spectrum covers 3000-8000A and reveals no obvious absorption or emission lines. We place these constraints -- which are tighter than those presented in GCN 6031 -- on the redshift: (1) The absence of a Lyman limit requires z<2.3. (2) The absence of a damped Lya profile or obvious Lya forest requires z<1.4 (3) The absence of MgII absorption suggests z<0.1. Given that strong MgII absorption is a signature of nearly every long duration GRB to date, we have confidence in the third conclusion. On the other hand, the absence of obvious [OII] or Halpha emission is surprising. If the GRB is at very low redshift, the absence of any source in the DSS imaging at this GRB position suggests a significantly sub-L* host. We strongly urge groundbased and spacebased follow-up programs to plan an intensive campaign to search for and characterize any associated supernova. Further analysis is in progress."