TITLE: GCN CIRCULAR NUMBER: 38731 SUBJECT: GRB 241229A: SAO RAS optical observations DATE: 24/12/30 16:54:52 GMT FROM: Moskvitin Alexander at SAO RAS <mosk@sao.ru> A. S. Moskvitin, O. I. Spiridonova (SAO RAS), A. S. Pozanenko (IKI RAS) report on behalf of the GRB follow-up team. We partially covered the error circle of SVOM/ECLAIRs GRB 241229A (Liang et al., GCN 38697) with the 1-m telescope of SAO RAS, Zeiss-1000 equipped with the CCD-photometer. We obtained 6 x 300 sec. images in Rc band on 2024-12-29T23:40:01--2024-12-30T00:16:47 (t_mid - T0 = 23.9 hours). Within the enhanced XRT position (Williams et al., GCN 38728) of X-ray candidate previously reported by Evans (GCN 38711) and Jiang et al. (GCN 38726, EP-FXT candidate #2) we did not detect any new source down to the limiting magnitude of R_lim = 22.3. We should note the presence of the nearby galaxy J125129.26+314455.4 visible in archive images with the brightness of R2 = 20.39 (USNO-B1) and r = 20.402 +/- 0.043 (SDSS). In our stacked frame we measured the brightness of the galaxy as R = 20.26 +/- 0.05 (diameter of aperture 9".94, calibrated against R2 magnitudes of nearby USNO-B1 stars). The angular distance from EP candidate position to the measured center of the galaxy is 2".5 (corresponding 18 kpc, z_phot = 0.2875, H0 = 72 km/s/Mpc), and 6".7 (47 kpc) from XRT position to the galaxy. View this GCN Circular online at https://gcn.nasa.gov/circulars/38731. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...