TITLE: GCN CIRCULAR NUMBER: 33550 SUBJECT: GRB 230328B : GRANDMA/Kilonova-Catcher optical detection DATE: 23/03/31 20:37:22 GMT FROM: Damien Turpin at NAOC (CAS) dturpin-astro@hotmail.com
F. Kugel (KNC), D. Turpin (CEA), S. Karpov (FZU), T. Hussenot-Desenonges (IJCLab), S. Antier (OCA/Artemis), P.A. Duverne (APC, U. Paris Cit�), P. Hello (IJCLab), A. Klotz (OMP/IRAP) report on behalf of the GRANDMA/Kilonova-Catcher collaboration:
The Kilonova-Catcher telescope network responded to the alert of GRB 230328B (Swift detection: Gropp et al., GCN 33527; Fermi GBM detection: Veres et al., GCN 33526).
The KNC observations were taken by F. Kugel with an ARTEMIS CCD ATIK-460ex camera mounted in the 0.4-m f/2.8 reflector telescope in the Chante-Perdrix Observatory (France). The afterglow is detected in the 36x60s unfiltered coadded images at about 5.2 hours (midtime of the exposure) after the Swift/BAT trigger time.
Below, we report our photometric measurement in Rc magnitude. ------------------------------------------------------------- T-T0 (day) |Exposure| Filter | Mag +/- err |Mag.Lim. (AB) ------------------------------------------------------------- 0.22172 | 36 x 60s | Rc | 20.19 +/- 0.10 | 21.4 (3 sigma)
Our detection is consistent with the detections and limits previously reported in Pankov et al., GCN 33528.; Belkin, GCN 33530; Lu et al., GCN 33534; Catapano et al., GCN 33535; Suresh et al., GCN 33536.; Adami et al., GCN 33537; Gompertz et al., GCN 33538; Komesh et al., GCN 33539; Lu et al., GCN 33540; Ror et al., GCN 33547; Agui Fernandez et al., GCN 33549
The GRANDMA/Kilonova-Cacther images have been calibrated using field stars from the PanSTARRS-DR1 catalog using the STDpipe pipeline (Karpov 2022) and the ps1/r to Rc mag conversion from (Pancino et al. 2022).
GRANDMA is a worldwide telescope network (grandma.ijclab.in2p3.fr) devoted to the observation of transients in the context of multi-messenger astrophysics (Antier et al. 2020 MNRAS 497, 5518). Kilonova-Catcher (KNC) is the citizen science program of GRANDMA (http://kilonovacatcher.in2p3.fr/).