TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2011 SUBJECT: GRB 030329: Optical pre-Imaging DATE: 03/03/30 00:49:05 GMT FROM: Josh Bloom at Harvard/CFA GRB 030329: Optical pre-Imaging C. Blake (Princeton) and J. S. Bloom (CfA) report: "Using a signal-to-noise weighted stack of 50 NEAT images (taken from 1997-2002), we do not detect a counterpart at the position of the transient afterglow of GRB 030329 (Price & Peterson; GCN #1985). The images were acquired by R. Bambery, S. Pravdo, M. Hicks, and K. Lawrence (Near-Earth Asteroid Tracking Project, Jet Propulsion Laboratory). We therefore estimate the upper limit to the brightness of any host galaxy as R=23.1 (2 sigma) or R=22.5 (3 sigma). This result is consistent with the somewhat more shallow limits reported in Wood-Vasey et al. (GCN #1998). The absence of a host to such magnitude levels suggests a redshift of z >~ 0.2, despite the extreme brightness of the early afterglow. Within 7.5 arcseconds of the position of the OT, we find two sources that are marginally detected (at the R=22.5 mag level): ------------------------------------------------------------------ RA(J2000) DEC Source-->OT ------------------------------------------------------------------- A: 10:44:49.776, +21:31:16.49 3.54" East, 1.66" North d=3.91" B: 10:44:50.065 +21:31:10.77 -0.49" East, 7.38" North, d=7.40" Positional errors relative to the USNO-B1.0 catalog are 0.5". These sources are shown in an image linked from the webpage given below. Photometric calibration of the stacked image was performed using the USNO-B1.0 catalog. Some photometric secondary stars in the field are listed below: RA(J2000) DEC R B mag mag ----------------------------------------------------- 10:44:55.17 +21:28:11.3 17.69 18.48 10:44:43.40 +21:27:58.4 18.41 19.46 10:44:44.06 +21:27:18.5 18.52 20.47 10:44:53.61 +21:30:11.6 17.45 18.41 10:45:04.39 +21:29:56.1 18.22 20.37 10:44:55.67 +21:31:22.2 19.08 19.95 10:44:54.97 +21:31:42.7 18.51 20.36 10:44:48.68 +21:31:39.8 18.95 19.30 10:44:42.00 +21:32:31.7 15.08 18.18 10:44:50.44 +21:32:05.8 16.61 17.99 10:44:59.44 +21:31:43.9 18.07 19.84 ------------------------------------------------------- Finally, we note an object at (J2000) 10:44:55 +21:31:05.9, which appeared in the DSS-II image, and is listed in the USNO-B1.0 as being R=19.60, was detected at only R=21.9 in our stacked image." A stacked image from NEAT that includes the WCS in the header may be found at: http://astro.princeton.edu/~cblake/030329.html This message can be cited.