TITLE: GCN CIRCULAR NUMBER: 35463 SUBJECT: GRB 240101B: MarSEC Observatory, Vicenza, Italy, UPPER LIMIT DATE: 24/01/02 20:34:34 GMT FROM: I. Peretto at MarSEC (Marana Space Explorer Center) <ricerca@marsec.org> Ivo Peretto (MarSEC, Marana Space Explorer Center, Marana Di Crespadoro, VI, Italy) Member of: UAI/SSV - Unione Astrofili Italiani/Sezione Stelle Variabili, GRB section. AAVSO (American Association Variable Stars Observers) In collaboration with: Stefano Lora (MarSEC, Marana Space Explorer Center, Marana di Crespadoro, VI, Italy) report: We imaged the field of GRB 240101B detected by SWIFT(trigger=1205744) with the telescope 14” RC Officine Stellari of MarSEC (Marana Space Explorer Center). The observations with a series of 120 sec exposures started at 2024-01-01 21:42:43 UT, 77 min. after the GRB trigger, with a Ritchey-Chretien telescope D=360 mm f/ 8. at the following position: RA(J2000) = 23h 28m 12s Dec(J2000) = +51d 38' 43" Weather conditions were medium with Moon illuminated 70% at 2° from the horizon. We co-added 30 exposures of 120 sec each. Start T0+ End T0+ V lim. 77 min 137 min 20.12 We did not found any optical counterpart in A.R. 23 28 12, DEC. +51 38 43 position and in the error box of the XRT candidate. ref.: S. B. Cenko (GSFC) et al., GCN Circular 35449 Magnitudes were estimated with the Gaia DR3 and are not corrected for galactic dust extinction. Reference: https://www.marsec.org/ The message may be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/35463. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...