GCN Circular 6739
D. A. Perley (UC Berkeley), C. C. Thoene (DARK, UCB), J. Cooke (UC Irvine), J. S. Bloom (UCB), and E. Barton (UCI) report: Starting at 06:21:52 UT (2007-08-10), we imaged the field of GRB 070809 (GCN 6728), a short or intermediate-duration (GCN 6732) burst, with the Keck I telescope (+LRIS). We obtained under very high airmass (>2.6) and intervening cirrus 4x300 seconds of imaging in R band and 4x330 seconds in g band. At the edge of the refined XRT error circle (GCN 6737) we detect a single, faint source in both filters, with coordinates: RA = 13:35:04.55 dec = -22:08:30.8 (err: 0.4") Relative to the USNO B1.0 star at 13:35:09.80 -22:09:15.9 (R2=19.55) we measure a preliminary magnitude of R~24.0. It is not possible to tell whether the object is fading, but it does not appear visibly extended. We note also the presence of an edge-on galaxy near the error circle, at coordiates of 13:35:04.25, -22:08:26.8. No other objects are present in or near the error circle to a limiting magnitude of R~25.5. An image of the field is available at http://lyra.berkeley.edu/~dperley/070809/070809keckR.png .