GCN Circular 32640
Subject
Swift J1913.1+1946: Optical photometry
Date
2022-10-10T00:31:02Z (2 years ago)
From
Eric Broens at Vereniging Voor Sterrenkunde <eric.broens@skynet.be>
Eric Broens (Mol, Belgium) reports:
Following the detection of the bright hard X-ray and optical transient
Swift J1913.1+1946 (Dichiara et al., GCN 32632; Lipunov et al., GCN 32634),
which is possibly a GRB (Kennea & Williams, GCN 32635; Veres et al.,
GCN 32636), photometric observations were obtained using a 0.28-meter SCT
telescope equiped with a Moravian G2-1600 CCD camera and Astrodon
Johnson-Cousins BVRcIc filters.
The observations started at 19:13:48 UT on 2022-10-09.
Five 180 s exposures were average combined for each filter.
The following magnitudes were measured using three APASS DR9 field stars.
The APASS DR9 r' and i' magnitudes were transformed to Cousins Rc and Ic
using the Jester et al. (2009, AJ 130, 873) relations.
The afterglow was not detected in the B filter with a 5-sigma upper limit
of B = 17.8.
Date [UT] Filter mag
------------------- ------ ---------------
2022-10-09 19:21:21 B >17.8 (5-sigma)
2022-10-09 19:36:30 V 17.48 +/- 0.02
2022-10-09 19:51:40 Rc 16.60 +/- 0.05
2022-10-09 20:06:50 Ic 15.76 +/- 0.06
These magnitudes are not corrected for galactic extinction.