TITLE: GCN CIRCULAR NUMBER: 36565 SUBJECT: LIGO/Virgo S240527fv: GRANDMA/FRAM-Auger Optical Observations DATE: 24/05/29 16:29:35 GMT FROM: Nidhal Guessoum at AUS, UAE <nguessoum@aus.edu> S. Karpov (FZU), M. Prouza (FZU), M. Masek (FZU), H. Peng (THU), W. Corradi (LNA), A. Le Calloch (UCB), N. Guessoum (AUS), S. Antier (OCA), C. Andrade (UMN), M. Coughlin (UMN), P. Hello (IJCLAB), P.A Duverne (APC), T. Pradier (Unistra/IPHC), D. Turpin (CEA-Saclay/Irfu) Report on behalf of the GRANDMA collaboration: Coordinated through Skyportal (https://skyportal-icare.ijclab.in2p3.fr/), we performed tiled observations of LIGO/VIRGO event S240527fv (GCN 36551) with the FRAM-Auger (30cm ODK + CCD MII G4-16000, 60' x 60' field of view, Pierre Auger Observatory, Malargue, Argentina) telescope. Observations were conducted from 2024-04-29 08:10:26.076 to 2024-04-28 09:46:05.081, beginning approximately 33.0 hr after the GW trigger time, under moderate weather conditions. Using the Bilby skymap as a reference, we searched 43.7% (e.g 20.6 sq deg) of the localization region, acquiring 40 consecutive 2-minute long exposures in Johnson R filter at the individual pointings as described below: +------------+--------------+----------+----------+-----------+ | Date | Time | Filter | Exposure | Limiting | | | (UTC) | | (s) | Magnitude | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:10:26.076 | R | 120.0 | 14.91 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:12:37.678 | R | 120.0 | 14.56 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:15:00.776 | R | 120.0 | 14.34 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:17:12.432 | R | 120.0 | 13.64 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:19:33.063 | R | 120.0 | 14.16 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:21:44.737 | R | 120.0 | 14.22 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:24:05.386 | R | 120.0 | 15.34 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:26:16.903 | R | 120.0 | 15.62 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:28:37.672 | R | 120.0 | 14.26 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:30:49.260 | R | 120.0 | 14.34 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:33:10.230 | R | 120.0 | 13.83 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:35:21.850 | R | 120.0 | 13.21 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:37:43.128 | R | 120.0 | 13.72 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:39:54.712 | R | 120.0 | 12.58 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:42:16.535 | R | 120.0 | 12.65 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:44:28.200 | R | 120.0 | 12.36 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:46:47.697 | R | 120.0 | 12.82 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:48:59.325 | R | 120.0 | 13.57 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:51:21.246 | R | 120.0 | 12.53 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:53:32.809 | R | 120.0 | 12.76 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:55:55.340 | R | 120.0 | 13.66 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 08:58:06.955 | R | 120.0 | 14.50 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 09:00:27.858 | R | 120.0 | 14.38 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 09:02:39.495 | R | 120.0 | 14.67 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 09:05:01.103 | R | 120.0 | 14.53 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 09:07:12.729 | R | 120.0 | 14.98 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 09:09:36.377 | R | 120.0 | 14.56 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 09:11:47.928 | R | 120.0 | 15.08 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 09:14:08.980 | R | 120.0 | 15.69 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 09:16:20.612 | R | 120.0 | 15.51 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 09:18:43.580 | R | 120.0 | 15.34 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 09:20:55.200 | R | 120.0 | 15.61 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 09:30:19.249 | R | 120.0 | 15.17 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 09:32:30.827 | R | 120.0 | 14.81 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 09:34:50.198 | R | 120.0 | 15.26 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 09:37:01.946 | R | 120.0 | 14.94 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 09:39:22.748 | R | 120.0 | 15.20 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 09:41:34.360 | R | 120.0 | 15.29 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 09:43:53.433 | R | 120.0 | 15.33 | |------------+--------------+----------+----------+-----------+ | 2024-05-29 | 09:46:05.081 | R | 120.0 | 15.30 | |------------+--------------+----------+----------+-----------+ Our low latency analysis (Karpov et al. 2021) did not reveal any significant candidate down to the limits listed in the table above (5 sigma, AB system). GRANDMA (Global Rapid Advanced Network Devoted to the Multi-messenger Addicts) is a network of robotic telescopes connected all over the world with both photometry and spectrometry capabilities for Time- domain Astronomy (https://grandma.lal.in2p3.fr/). Details on the FRAM telescopes are available on the GRANDMA web pages or on https://grandma.ijclab.in2p3.fr/fram/ View this GCN Circular online at https://gcn.nasa.gov/circulars/36565. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...