GCN Circular 6126
N. Mirabal and J. P. Halpern (Columbia U.) report on behalf of the MDM Observatory GRB follow-up team: "We have observed the Swift location of GRB 070223 (Vetere et al., GCN 6125) with the MDM 1.3m telescope at a mean epoch Feb. 23, 02:18 UT (~1 hr post-burst). Inside the XRT error circle, we find no new optical sources to preliminary limiting magnitudes R > 20.3, I > 20.0. Observations are ongoing. This message may be cited."