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GCN Circular 4596

GRB 060124: ART optical limits during the burst
2006-01-25T12:45:04Z (18 years ago)
Ken ichi Torii at RIKEN <>
K. Torii (Osaka U.) reports on behalf of the ART collaboration:

 The error region of GRB 060124 (Holland et al., GCN 4570) was imaged
with the two Automated Response Telescopes in Toyonaka, Osaka, under
cloudy condition. The observations started before the arrivals of the
three major gamma-ray pulses (Fenimore et al. GCN 4586).

 The older 14 inch telescope, ART-3a, imaged the field starting at
15:55:59 UT (67 s after the BAT trigger). 60 s integrations were
repeated through each of the four linear polarizers (effective in
400-700 nm) in the filter wheel. The relative position angles between
the filters are 45 degrees. We did not detect any optical flare at the
position of the optical afterglow (Kann, GCN 4577; Kann, Henze, &
Laux, GCN 4579), in the first two frames, before the field was
completely clouded after ~15:58 UT (3.5 minutes after the trigger).

 A new 0.35m f/6 telescope, ART-3b, observed the field starting at
15:56:11 UT (79 s after the BAT trigger). Repeated 60 s integrations
were made through the standard Ic filter. We did not detect any
optical flare either, in the first two frames, and the later frames
were clouded.

 The following 3-sigma limits are derived for an optical transient
during the gamma-ray burst. The ART-3a and ART-3b magnitudes were
calculated with reference to USNO-B1.0 R2 and I magnitudes,

StartUT		Limits
15:55:59	>14.6R
15:56:11	>14.9I
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