From: Robert A. Knop Jr. (robert.a.knop@vanderbilt.edu)
Date: Sat May 22 2004 - 17:10:18 PDT
Bear in mind that there are an infinite number of cosmic rays in the
I-band images. The references, however, being a sum of many images,
don't have cosmic rays.
As such, yes, the sub and new images are going to look very similar,
since all those CRs will still be there.
The trick is to find some *real* objects and see if those subtract. If
they don't, then maybe there's a ratio problem.
-Rob
On Sat, May 22, 2004 at 05:04:52PM -0700, Vitaliy Fadeyev wrote:
>
> Robert A. Knop Jr. wrote:
>
> > The main thing people should do now is go through the saved
> > candidates, get I-band magnitudes if possible, and check to see if
> > they are on the April subtractions.
> >
> I looked up the I-band information. Most candidates fall into one of the
> 3 cathegories:
> a) clear signal, b) no signal or fluctuation, c) there is a CR in that
> place. Could not really
> conclude anything about candidates # 0 and 1. They are on subtractions
> |acs04maysub-i/norm01i,
> |for which the "new" images looks exactly the same as the subtraction in
> the tiles.
> The "global" images for the new and the subtraction are very similar as
> well, with
> the subtraction showing slightly less flux than the new. It seems that
> the reference
> image calibration is off (scaled down). Therefore I cannot trust the
> information for
> these candidate.
>
> vitaliy
>
>
>
-- --Prof. Robert Knop Department of Physics & Astronomy, Vanderbilt University robert.a.knop@vanderbilt.edu
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