GRB 230314A: TURBO Optical Upper Limit

We observed the GRB 2303014A (Fermi GBM Team, GCN 33474) field with the Total-Coverage Ultrafast Response to Binary-Mergers Observatory (TURBO) prototype telescope in St. Paul, Minnesota on March 14, from 05:02 to 08:36 UT (corresponding to 2.01 to 5.52 hours after GRB trigger) in SDSS g and r-band filters. We acquired a series of 30x60s exposures over the entire observing period in each band covering an area of about 12 square degrees with corners for each field listed in the table below. We do not detect any fading sources in the GBM error region in either band, consistent with available optical upper limits (Lipunov et al., GCN 33249). The following 3-sigma upper limits in AB magnitudes are calculated using the Pan-STARRS catalog as reference: Filt. | Corners of fields (hh:mm:ss,dd:mm:ss)| Upper Limit ---------------------------------------------------------------------------------------------- g | (15:08:41,+75:20:31) ,(16:08:31,+74:24:12) |18.2 ---------------------------------------------------------------------------------------------- r | (16:06:24,+75:12:04) ,(15:08:34,+74:04:37) |18.6 ---------------------------------------------------------------------------------------------- g | (15:20:58,+75:20:08) ,(16:20:45,+74:23:31) |18 ---------------------------------------------------------------------------------------------- r | (16:18:28,+75:12:01) ,(15:20:35,+74:03:47) |18.7 ---------------------------------------------------------------------------------------------- g | (15:12:17,+73:21:35) ,(16:05:17,+72:25:04) |18.3 ---------------------------------------------------------------------------------------------- r |(16:03:27 ,+73:12:08) ,(15:12:06,+72:04:05) |18.7 ---------------------------------------------------------------------------------------------- g | (15:24:16,+73:21:38) ,(16:17:16,+72:25:03) |18.1 ---------------------------------------------------------------------------------------------- r | (16:15:22,+73:12:30) ,(15:23:58,+72:04:42) |18.7 ---------------------------------------------------------------------------------------------- g | (15:04:23,+77:18:32) ,(16:13:02,+76:22:15) |18.2 ---------------------------------------------------------------------------------------------- r | (16:10:49,+77:10:25) ,(15:04:38,+76:01:38) |18.6 ---------------------------------------------------------------------------------------------- g | (15:16:20,+77:18:47) ,(16:24:59,+76:22:30) |18.1 ---------------------------------------------------------------------------------------------- r | (16:22:46,+77:10:29) ,(15:16:35,+76:01:37) |18.7 These magnitudes are not corrected for foreground Galactic extinction. The TURBO prototype in St. Paul consists of two co-mounted 11-inch telescopes each with a 6.6 square degree field of view. TURBO will consist of two arrays of 8 pairs of co-mounted 11-inch telescopes at two dark-sky sites: Magdalena Ridge Observatory, New Mexico, USA and Skinakas Observatory, Crete, Greece.