GCN Circular 30401
Subject
GRB 210704A: OAJ T80 multi-color detections
Event
Date
2021-07-07T10:40:21Z (5 years ago)
From
Alexander Kann at IAA-CSIC <kann@iaa.es>
D. A. Kann (HETH/IAA-CSIC), A. de Ugarte Postigo (HETH/IAA-CSIC,
DARK/NBI), C. Thoene, M. Blazek, J. F. Agui Fernandez (all
HETH/IAA-CSIC), N. Maicas, and J. L. Lamadrid (COAJ report:
We observed the afterglow of GRB 210704A (BALROG localization:
Kunzweiler et al., GCN #30369; Fermi/LAT detection: Berretta et al., GCN
#30375; Fermi/GBM detection: Malacaria & Meegan, GCN #30382; AGILE/MCAL
detection: Ursi et al., GCN #30372; AstroSat/CZTI detection: Prasad et
al., GCN #30378; Konus-Wind detection: Ridnaia et al., GCN #30388;
Swift/XRT afterglow detection: D'Ai et al., GCN #30379) with the T80
0.8m telescope at the Observatorio de Javalambre (Teruel, Spain).
Observations consisted of 3 x 300 s in z', i', g' r' each, at midtimes
1.081, 1.093, 1.104, and 1.116 days after the GRB, respectively.
The afterglow (Kim et al., GCN #30384, D'Avanzo et al., GCN #30385, Kann
et al., GCN #30391, de Ugarte Postigo et al., GCN #30392) is
well-detected in g'r', faintly in i' and not in z'. Against four
Pan-STARRS field stars, we measure (AB magnitudes):
g' = 22.42 +/- 0.11 mag;
r' = 22.17 +/- 0.10 mag;
i' = 22.08 +/- 0.23 mag;
z' > 21.5 mag
at the above-mentioned mid-times.