GCN Circular 33038
Subject
GRB 221009A: MuSCAT3 observations
Date
2022-12-10T03:40:25Z (a year ago)
From
Mariko Kimura at RIKEN <mariko.kimura@riken.jp>
M. Kimura (RIKEN), K. Isogai (Tokyo Univ./Kyoto Univ.), M. Arimoto,
D. Yonetoku (Kanazawa Univ.),
N. Narita, M. Tamura (Tokyo Univ./Astrobiology Center),
A. Fukui�� (Tokyo Univ.), M. Ikoma (NAOJ)
We have monitored the afterglow of GRB 221009A since three days
after the Swift and Fermi alerts (GCN 32632; GCN 32636) by MuSCAT3
on the 2-meter telescope at Las Cumbres Observatory.
MuSCAT3 is multi-channel imagers with the filters of SDSS g', r', i', zs,
which is designed for observing transiting exoplanets.
https://lco.global/observatory/instruments/muscat3/
The measurements are here:
BJD���������������������������������������� Mag������ Err���� Filter
2459864.82404�� 21.33�� 0.15�� g
2459864.82404�� 20.01�� 0.03�� r
2459864.82404�� 19.48�� 0.03�� i
2459864.82404�� 18.26�� 0.01�� z
2459870.80681�� 23.55�� 0.21�� g
2459870.80681�� 21.74�� 0.05�� r
2459870.80681�� 20.47�� 0.04�� i
2459870.80681�� 19.90�� 0.03�� z
2459872.82760�� 23.64�� 0.26�� g
2459872.82760�� 21.91�� 0.07�� r
2459872.82760�� 20.82�� 0.06�� i
2459872.82760�� 20.22�� 0.05�� z
2459876.80690�� 23.99�� 0.34�� g
2459876.80690�� 21.96�� 0.09�� r
2459876.80690�� 21.00�� 0.08�� i
2459876.80690�� 20.50�� 0.07�� z
By plotting these data with the other optical measurements reported to GCN
(GCNs 32625, 32640, 32644, 32645, 32646, 32652, 32659, 32662, 32666,
32667, 32670, 32678, 32679, 32692, 32693, 32705, 32709, 32729, 32730,
32743, 32750, 32758, 32769, 32771, 32799, 32809, 32818),
we found that the optical afterglow light curve shows a power-law decay, and
only i'-band light curve fluctuates along the decline possibly because of
systematic errors.
We did not find a bump reported by GCN 32818 at least around a week after
the Swift and Fermi trigger.
If you have any queries, please contact M. Kimura at the following address.
mariko.kimura@riken.jp