TITLE:   GCN CIRCULAR
NUMBER:  32342
SUBJECT: GRB 220706A: LCO Optical Upper Limits
DATE:    22/07/08 01:42:44 GMT
FROM:    Robert Strausbaugh at U. of the Virgin Islands  <robert.strausbaugh@uvi.edu>

R. Strausbaugh (U. of the Virgin Islands), A. Cucchiara (College of Marin) report on behalf of a larger collaboration:

We observed the Swift GRB 220706A (D'Ai et al., GCN 32329) field with the Siding Spring Observatory, Australia site, on July 6, from 18:15 to 18:52 (corresponding to 2.10 to 2.72 hours from the GRB trigger time) with the SDSS r and i filters.

We performed a series of 3x300s exposures in i and 2x300 and 1x135 r bands (the last r-band observation was interrupted).  We do not detect an optical counterpart within the XRT enhanced error region (Goad et al., GCN 32333) in either band, consistent with other non-detections (Gendre et al., GCN 32331; Lipunov et al., GCN 32332; Jiang et al., GCN 32335; de Ugarte-Postigo et al., GCN 32338; Guelbenzu et al., GCN 32339).

The following upper limits are calculated using the PanSTARRS catalog as reference:

r>23.0
i>22.5

We also observed with the LCO 1-m Sinistro instrument at the Teide Observatory, on Tenerife, on July 7, from 04:25 to 04:52 UT (corresponding to 12.27 to 12.72 hours from the GRB trigger time) with the SDSS r and i filters.

We performed a series of 3x300s exposures in i and r bands.

The following upper limits are calculated using the PanSTARRS catalog as reference:

r>22.4
i>22.4

These magnitudes are not corrected for galactic extinction.

R.S. is funded by NSF AST grant #1831682