TITLE: GCN CIRCULAR NUMBER: 34405 SUBJECT: GRB 230812B: Detected Optical Afterglow Candidate DATE: 23/08/13 17:32:55 GMT FROM: Mohammad Odeh at Al Khatim Observatory M44 Mohammad Odeh, Osama Ghannam, Anas Mohammad, Khalfan Al-Noaimy, and Sameh Al-Ashi, report on behalf of Al-Khatim Observatory (AKO) operated by the International Astronomical Center in Abu Dhabi, UAE: We observed the field of GRB 230812B (Lesage et al., GCN 34387; Scotton et al., GCN 34392; Page, GCN 34394; Zheng & Filippenko, GCN 34395; Lipunov et al., GCN 34396; Salgundi et al., GCN 34397; Ackley et al., GCN 34398; Xiong et al., GCN 34401; Casentini et al., GCN 34002; Frederiks et al., GCN 34403; Mao et al., GCN 34404), with our 0.36m f/7.7 robotic telescope. The observation was done on 13 August 2023 from 16:15 to 16:47 (UT), about 21.6 hours from the trigger. We obtained multiple 180-sec exposures in Ic filter. We detected an optical afterglow candidate at: R.A. (J2000): 16:36:31.45 Dec. (J2000): +47:51:32.3 That is the same localization of (Zheng & Filippenko, GCN 34395), which is about 5.5 arcsec from the improved Swift/XRT localization (Page, GCN 34394). The following observation was calculated using Atlas catalogue as a reference: ----------------------------------------------------------------------------- ObsTime (mid), Exposure (sec), Filter, Mag ----------------------------------------------------------------------------- 2023-08-13T16:32:40Z, 10 x 180s (stacked), Ic, 18.8 +/- 0.21 ----------------------------------------------------------------------------- The magnitude is not corrected for galactic extinction.