TITLE: GCN CIRCULAR NUMBER: 35787 SUBJECT: Transient EPW20240219aa: Mondy optical observations DATE: 24/02/24 13:32:36 GMT FROM: Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru> N. Pankov (HSE, IKI), A. Pozanenko (IKI), E. Klunko (ISTP), S. Belkin (IKI, HSE) report on behalf of IKI-GRB-FuN: We observed the field of a likely GRB event EPW20240219aa (Zhang et al., GCN 35773) which was also detected by Fermi GBM (Fletcher et al., GCN 35776; Mangan & Meegan, GCN 35778), Swift BAT (DeLaunay et al., GCN 35784), and and Insight-HXMT/HE (Cai et al., GCN 35785) with AZT-33IK telescope of Sayan observatory (Mondy). The observations started on 2024-02-23 (UT) 12:31:49, i.e. t-T0 = 4.276478 days after trigger. We took 30x120 sec frames in R-filter. After human vetting we list the two potential galaxies candidates, which show brightness excess more than 3sigma in comparison with USNO-B1.0 catalog. RA Dec Mag Err USNO_B10 R2 Class* Sigma excess -- --- --- --- -------- -- ----- ----- 05 19 56.874 +25 29 43.69 18.00 0.13 1154-0071628 19.15 G 4.07 05 20 17.951 +25 33 08.34 18.63 0.12 1155-0072251 19.47 G 3.03 * G -- Galaxy According to our classifier based on PS1 colours, source FWHM, and SIMBAD query. The photometry performed against nearby USNO-B1.0 stars (R2 magnitude). The limiting magnitude (3sigma) is R=21.5. View this GCN Circular online at https://gcn.nasa.gov/circulars/35787. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...