TITLE: GCN CIRCULAR NUMBER: 31804 SUBJECT: GRB 220325A: GRANDMA observations DATE: 22/03/29 18:08:27 GMT FROM: Sarah Antier at OCA sarah.antier@oca.eu
C. Andrade, M. Coughlin (UNM), K. Noysena (NARIT), W. Kiendrebeogo (UJS), I. Tosta e Melo (INFN-LNS), X. F. Wang (TSU/BJP), F. Navarete (NOIRLab/SOAR) J. Zhu (BJP), L. Wang (XAO), A. Iskandar (XAO), X. Zeng (XAO), L. Abe, Ph. Bendjoya, J.-P. Rivet (Lagrange/OCA), D. Vernet (Galilee/OCA), S. Antier, A. de Ugarte Postigo (Artemis/OCA), A. M. Fouad, A. Taky, A. Shokry, I. Elhousiny, A. Eid, M. Farouk (NRIAG), P.A. Duverne (IJCLAB) report on behalf of the GRANDMA collaboration:
The GRANDMA telescope network responded to the alert of GRB 220325A (Palmer et al. GCN 31787). The first observations started 4.28 h after the BAT trigger time.
No new object was detected within the XRT enhanced error region (Evans et al. GCN 31794). In the following table we report the preliminary photometry of our observations. Upper limits are reported at the 3-sigma limit, in the AB system.
T-T0 (hr)| MJD | Observatory| Exposure| Filter | Upp.Lim. (AB) _____________________________________________________________________ 04.28 |59663.89971| SNOVA | 9x300s | Bessel R | 20.1 04.44 |59663.90475| NOWT | 11x180s | Bessel R | 19.7 08.11 |59664.05765| KAO | 22x50s | SDSS i | 21.2 10.14 |59664.14304| C2PU | 16x240s | SDSS r | 20.8
These limits are consistent with the non-detections previously reported (Gupta et al. GCN 31793, Strausbaugh et al. GCN 31795, Nicuesa Guelbenzu et al. GCN 31797).
The photometry of NOWT and SNOVA was performed using field stars from the APASS catalog. The KAO and C2PU image have been processed using field stars from the PanSTARRS-DR1 catalog and with the MUPHOTEN pipeline (Duverne et al. 2021).
The magnitudes are not corrected for the Galactic extinction in the direction of the burst.
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/).