TITLE:   GCN CIRCULAR
NUMBER:  34252
SUBJECT: GRB 230723B: Montarrenti Observatory upper limit
DATE:    23/07/24 18:30:42 GMT
FROM:    Simone Leonini at Montarrenti Observatory (Siena, Italy) <s.leonini@iol.it>

S. Leonini, M. Conti, P. Rosi, L.M. Tinjaca Ramirez and L. Bellizzi (Montarrenti Observatory, Siena, Italy) report:

We observed the field of the GRB 230723B (Trigger 1180410, K.L. Page et al., GCN 34234, V. Lipunov, GCN 34239; J.F. Agui Fernandez, GCN 34241; C. Adami, GCN 34247; U. Quadri, GCN 34250; J.F. Agui Fernandez, GCN 34251) with the automatic 0.53m Ritchey-Chretien telescope + U47 detector at Montarrenti Observatory (Siena, Italy, IAU code C88).

The observations were started under good weather conditions at 2023-07-23 21:13:37 UT (approximately 9.5 hours after notice) stacking 30x30s clear filter CCD exposures.

We have not found optical transient within the error-box of the Neil Gehrels Swift Observatory position (RA 16h 41m 30.74s, Dec. -05d 20m 04.7s - J2000).  
Mag. upper limit R = 20.83 +/-0.14

Magnitudes were obtained from USNO-B1 catalogue and are not corrected for galactic extinction.