TITLE: GCN CIRCULAR NUMBER: 40316 SUBJECT: GRB 250430A: Optical Observations via Virtual Telescope Project, Italy DATE: 25/05/02 11:22:42 GMT FROM: Gianluca Masi at Virtual Telescope Project <gianluca@bellatrixobservatory.org> Gianluca Masi, Virtual Telescope Project (Italy), reports: We attempted to observe the optical counterpart (Parsotan et al., GCN 40292; Odeh et al., GCN 40295) of GRB 250430A with the 14” robotic unit available at the Virtual Telescope Project facility in Manciano, Italy, equipped with a KAF-3200E based CCD camera, its QE peaking (90%) in the red part of the spectrum. We collected 7, 300-second unfiltered exposures, then we averaged them. The central time of the resulting stack was 30 April, 22:19 UTC, that is about 4.75 hours after the burst. We detected a faint object at the following position (J2000.0): RA: 15 33 32.94s Decl.: -18 07 06.5 R= 20.8 (assuming R-mags from Gaia DR2 for the reference stars). This position is consistent with Odeh et al., GCN 40295. At the position above, there is a very faint source on Panstarrs DR1 images, as well as on DESI Legacy DR10 images (the latter mentioned by Garnichey et al., GCN 40301), likely the host galaxy of GRB 250430A. The image is available here: https://www.virtualtelescope.eu/2025/05/02/grb-250430a-detection-of-the-opti... View this GCN Circular online at https://gcn.nasa.gov/circulars/40316. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...