TITLE:   GCN CIRCULAR
NUMBER:  31977
SUBJECT: GRB 220430A: GRANDMA observations
DATE:    22/05/01 00:24:17 GMT
FROM:    Alain Klotz at IRAP-CNRS-OMP  <Alain.Klotz@free.fr>

D. Dornic (CPPM), A. Klotz (CNRS-OMP-IRAP), A. Sabahaddin (ShaO),
T. Midavaine (KNC), V. Rupchandani (AUS), P. A. Duverne (IJCLAB),
Y. Rajabov (UBAI), X. Song (BJP), X. F. Wang (THU/BJP), J. Zhu (BJP),
L. Wang,  X. Zeng, A. Iskandar (XAO), P. Thierry (AGORA),
A. Kaeouach (Tanger), Z. Benkhaldoun (OUCA),
S. Antier, A. de Ugarte Postigo (CNRS-OCA-ARTEMIS)
report on behalf of GRANDMA collaboration:

The GRANDMA telescope network responded to the alert of GRB 220430A
(Ambrosi et al. GCN 31972, Osborne et al., GCN 31973,
Groot et al., GCN 31974, Ursi  et al., GCN 31975,
Pozanenko et al. GCN 31976). The first observations
started 34 min after the SWIFT BAT trigger time.

We did not detect any optical transient within the XRT error box
during the first 2.9 hours. We report our 3-sigma upper limits.
Magnitudes are given in the AB system.

T-T0 (hr)| MJD       | Obser.   |Exposure| Filter| Upp.Lim. (AB)
0.56111  |59699.60204| SNOVA      | 4x300s | Clear | 19.0
2.59194  |59699.68666| Makes-T60| 10x120s| Clear | 19.5
6.24347  |59699.83880| HAO      | 20x120s| L     | 20.6
6.33472  |59699.84260| MOSS     | 30x60s | Clear | 21.0

The images have been calibrated with SDSS DR7.
T-T0 is the started date.

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/).