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GCN Circular 8985

GRB 090313: Sustained optical brightness
2009-03-13T13:45:27Z (15 years ago)
Daniel Perley at U.C. Berkeley <>
D. A. Perley, W. Li, R. Chornock, and A. V. Filippenko (UC Berkeley) 
report on behalf of the KAIT GRB team:

We continued observing the position of the optical afterglow (Chornock 
et al., GCN 8979) of GRB 080313 (Mao et al., GCN 8980) with the Katzman 
Automatic Imaging Telescope (KAIT) in unfiltered and I-band images 
lasting until 2.9 hours after the trigger.  In spite of significant 
contamination due to scattered light from the full moon 20 degrees away, 
we continue to (marginally) detect the afterglow in 30-second unfiltered 
and 120-second I-band exposures with a magnitude of I = 17.7 +/- 0.4 
(calibrated relative to nearby USNO standards) at this time.

Given the usually bright late-time optical afterglow, the equatorial and 
nearly anti-sun position, and the possibility of an association with the 
  bright nearby galaxy (the second object mentioned in Berger et al., 
GCN 8984, which has a spectroscopic redshift of z=0.0235 according to 
SDSS), and the unclear high-energy classification of this object 
(Sakamoto et al., GCN 8982) we strongly encourage continued follow-up in 
spite of the presence of the nearby moon.

[GCN OPS NOTE(13mar09): Per author's request, please see GCN 8988
that explains the mistaken sakamoto reference  and the high-energy statement
in the last sentence, as explained in the corerction GCN 8988.]
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