TITLE: GCN CIRCULAR NUMBER: 36026 SUBJECT: IceCube-240327B: GRANDMA observations of 4FGL J0555.9+0030 DATE: 24/04/04 14:49:34 GMT FROM: marion.pillas@ligo.org M. Pillas, S. Antier (OCA), T. Pradier (Unistra/IPHC), E. Elhosseiny (NRIAG), F. Magnani (CPPM), Sh. Agayeva, Z.Vidadi, N. Ismailov, A.Hasanov and S. Alisov. (ShAO), M. Prouza, S. Karpov, M. Masek, M. Blazek (FZU), A. Baransky, O. Pyshna, O. Sokoliuk, A. Simon, V. Vasylenko (Lisnyky), Z. Benkhaldoun, A. Kaeouch (OUCA,KNC), I. Tosta e Melo (UniCT-DFA), P. Hello (IJCLAB), M. Coughlin (UMN), C. Andrade (UMN), P-A Duverne (APC), D. Turpin (CEA-Saclay/Irfu); X. Wang (Tsinghua Uni), T. Sun (PMO): On behalf of GRANDMA collaboration: We observed the localization region of the neutrino event IceCube-240327B (Sommani et. al, GCN 35984, Mang et al., GCN 36005) and especially in optical the known gamma-ray source 4FGL J0555.9+0030, located at RA = 89.00 deg, Dec = 0.51 deg J2000, a potential gamma-ray source counterpart candidate (Sommani et. al, GCN 35984) We didn’t find any optical counterpart at the location of 4FGL J0555.9+0030 from 0.8 to 4.2 days post T0 = 2024-03-27, at 16:12:0.47 UT. Results are consistent with Stein et al., (GCN. 35989) In the following table, we report a subset of the preliminary photometry of our observations of 4FGL J0555.9+0030. Magnitudes are reported in Vega system. T-T0 day | MJD | Obser. | Exposure | Filter | Upper limit (5 sigma) —------------------------------------------------------------------------------------------------ 0.8 | 60397.52897106 | Yaonan-80 | 2x180s | Rc | 20.55 (Vega) 0.8 | 60397.52897106 | Yaonan-80 | 3x180s | B | 18.72 (Vega) 0.8 | 60397.52897106 | Yaonan-80 | 3x180s | Ic | 18.8 (Vega) 0.8 | 60397.52897106 | Yaonan-80 | 3x180s | V | 18 (Vega) 1.0 | 60397.70783564 | ShAO-T60 | 20x120s | V | 19.0 (Vega) 1.4 | 60398.05042824 | FRAM-Auger | 62X60s | Rc | 18.7 (Vega) 1.4 | 60398.05131481 | FRAM-Auger | 62X60s | V | 18.9 (Vega) 3.1 | 60399.74584491 | Lisnyky/AZT-8 | 29x60s | Rc | 18.8 (Vega) 3.1 | 60399.78062500 | Lisnyky/AZT-8 | 22x60s | Ic | 18.1 (Vega) 3.2 | 60399.85178840 | HAOs | 10x180 | V | 21.5 (Vega) 3.2 | 60399.87614483 | HAOs | 10x180 | Rc | 20.2 (Vega) 4.2 | 60400.88071398 | ASO | 10x180 | V | 21.9 (Vega) Johnson filters have been measured using the Gaia catalog (except for Yaonan-80 taken calibrated with USNO and UCAC4). All the data have been reduced by a single data processing pipeline STDPIPE (Karpov et al., 2022). We also run subtracted detection pipeline from Karpov et al., on the deepest images from HAOs and ASO at 3.2 days post T0 and couldn’t find any other new transient candidates within an 8 arcmin radius and 9 arcmin, respectively, around the location of 4FGL J0555.9+0030. GRANDMA is a worldwide coordinated telescope network (grandma.ijclab.in2p3.fr) devoted to the observation of transients in the context of multi-messenger astrophysics (Antier et al. 2020 MNRAS497, 5518). Kilonova-Catcher (KNC) is the citizen science program of GRANDMA (http://kilonovacatcher.in2p3.fr/). View this GCN Circular online at https://gcn.nasa.gov/circulars/36026. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...