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GCN Circular 32859

GRB 221024A: GRANDMA observations
2022-10-26T21:06:19Z (a year ago)
Cristina Andrade at UMN <>
C. Andrade (UMN), A. Iskandar (XAO), A. Klotz (IRAP-OMP), H. Peng (THU),
T. Sadibekova (AIM-CEA), M.Trevor (UMD), M. Freeberg (KNC),
D. Turpin (CEA), S. Antier (OCA/Artemis), A. Benkhaldoun (HAO),
S. Alishov(ShAO), E. Gurbanov(ShAO), E. Hesenov (ShAO), A. Kaeouach (HAO),
N. Kochiashvili (ShAO) K. Noysena (TRT), F.Guo(THU), Y.Rajabov (UBAI),
N. Sasaki (OPD), Z. Vidadi (ShAO),
report  on behalf of the GRANDMA collaboration:

The GRANDMA telescope network responded to the Swift-BAT alert of
GRB 221024A (R. Brivio et al., GCN 32827, J.P. Osborne et al. GCN 32839,
M. Capalbi et al. GCN 32846, A. Y. Lien et al. GCN 32854),
which is also detected by  Fermi (J. Wood et al. GCN 32835).

The first observations started 22 hours after the BAT trigger time.
The afterglow was reported detected within
the XRT enhanced error region by different teams: J. Strobl et al.
(GCN 32838) D50-telescope from ASU CAS; V. Swain et al. (GCN 32841)
0.7m GROWTH India Telescope; including UVOT observations and
N. P. M. Kuin et al. (GCN 32848).

In the following table we report the preliminary photometry of our
observations. Upper limits are reported at the 5-sigma limit,
in the AB system.

T-T0 (hr)|    MJD    |  Observatory| Filter    | Upp.Mag.
22.11   |59877.463197| KNC-NMSkies | ps1/r     | 19.7

Most of the sites were limited by the sky visibility and the weather
conditions. There is also light pollution from the nearby bright star
(Nu UMa, apparent mag (V) +3.490) located at ~6' from the XRT position.
Only one observation was successfully performed in the context of the
Kilonova-Catcher programme (KNC), a professional-amateur collaboration
within the GRANDMA project, by the T21 New Mexico skies iTelescope using
filter ps1/r. The KNC image have been processed using the STDpipe and
photometry was performed using field stars from the PanSTARRS1-r catalogue
as reference.

GRANDMA is a worldwide coordinated telescope network
(  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
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