TITLE:   GCN CIRCULAR
NUMBER:  31903
SUBJECT: GRB 220412A: GRANDMA observations
DATE:    22/04/15 12:13:31 GMT
FROM:    Patrice Hello at LAL  <hello@lal.in2p3.fr>

Subject Line:
GRB 220412A: GRANDMA observations

Content:

S. Beradze (AbAO), U. Bhardwaj (GRAPPA), T. Culino (ESILV), P. Hello
(IJCLAB), M. Masek (FZU), G. Raaijmakers (GRAPPA), Y. Rajabov (UBAI),
T. Sadibekova (AIM/CEA-UPS), F. Z. Guo (THU), X. F. Wang (THU/BJP), Y.
Zhu (NAOC), J. Zhang (NAOC), D. A. Kann (HETH/IAA-CSIC), K. Noysena
(NARIT), A. Kaouech (OUCA/KNC) C. Rinner (OUCA), Z. Benkhaldoun (OUCA),
S. Antier (OCA/Artemis), P. A. Duverne (IJCLAB), M. Freeberg (KNC),
R. Hainich (UP), F. Runger (UP), S. Karpov (FZU), A. Simon (Kyiv Univ),
A. Baransky (Kyiv Univ) and V. Godunova (IC ICAMER)
report on behalf of GRANDMA collaboration:

The GRANDMA telescope network responded to the alert of GRB 220412A
(N. J. Klingler et al. GCNC 31881, P.A. Evans et al. GCN 31887,
A. D'Ai et al. GCN 31888, K.L. Page et al GCN 31890).
The first observations started ** h after the SWIFT BAT trigger time.

We did not detect the optical afterglow within the first 24 h.
Upper limits are given in the AB system, at 3-sigma.


T-T0(hr)| MJD    | Observatory  | Exposure| Filter | Upp. Lim. (AB)
_____________________________________________________
05.55 |59681.50689|Xinglong-2.16m|12*300s    |  R     |   19.5
14.02 |59681.86193|OST/CDK20     |18*180s    |  R     |   17.8
14.07 |59681.85977|OST/CDK20     |17*180s    |  I     |   17.0
17.36 |59681.99881|KNC-HAO       |5*180s     |  L      |   17.3
21.18 |59682.15807|TRT-SRO       |10*60s     |  V       |   18.1
21.35 |59682.16537|TRT-SRO       |10*60s     |  R       |   17.7
21.53 |59682.17271|TRT-SRO       |10*60s     |  I       |   17.1
21.95 |59682.19014|KNC-T24       |3300s      |  I       |   18.1


The observations were contaminated by the moon.

These upper limits are consistent with previous reports of detections by
RATIR (Alan M. Watson et al., GCN 31882 & GCN 31902) and the upper limits
provided by UVOT (A. Breeveld and N. Klingler, GCN 31885), MITSuME Akeno
(K. L. Murata et al., GCN 31891).


The Xinglong-2.16m and TRT-SRO data have been calibrated using nearby stars
from the Pan-STARRS catalog. The measurements for  Xinglong-2.16m provided
by the STDPipe pipeline (Karpov 2022). The OST data have been using CDK
filter and calibrated with USNO-B1.0 Catalog (Monet+ 2003). The KNC-T24 and
KNC-HAO images have been calibrated using field stars from the 
PanSTARRS-DR1
catalog, measured with the MUPHOTEN pipeline (Duverne et al. 2021).


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/).