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GCN Circular 5

Subject
Untitled
Date
1970-01-01T00:00:00Z (55 years ago)
From
circulars@gcn.nasa.gov
GRB971024                                                              #005

The KPNO reduced 4m Mosaic (8k x 8k imager) data are now available on our
web page ( http://www.noao.edu/noao/grb/971024.html ).  As briefly stated
there, these data have been block averaged (binned) 2x2 to reduce the
image size to 4k x 4k.  The images are about 77 Mb each.  The seeing was
poor, about 1.5" on the first night and about 2" on the second night, so
with the ~0.25" Mosaic pixels the images are still well sampled after
binning.

The images were taken in the R-band and total 50 minutes exposure each.
Zero points are not yet available.

Buell Jannuzi, Arjun Dey and collaborators observed, processed, and
combined these images.  James Rhoads and Ted von Hippel have performed
preliminary photometry on these images and find a large number of objects
which deviate between the two epochs when comparing aperture photometry.
Most of the objects which deviate from one epoch to the other seem to be
due to crowding causing aperture photometry differences due to the
different seeing, and some are due to image defects.  Careful psf-fitting
photometry should improve the analysis.  We are still studying these
images but do not want to delay the efforts of others, so we are now
making the reduced images available.

This message is citable in publications.
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