Re: ACS noise(/depth?) variations - addendum

From: Robert A. Knop Jr. (robert.a.knop@vanderbilt.edu)
Date: Sun Apr 04 2004 - 14:55:36 PDT

  • Next message: Robert A. Knop Jr.: "Re: We should *first* go through good candidates WITH hosts (much higher priority)."

    On Sun, Apr 04, 2004 at 02:53:31PM -0700, Greg Aldering wrote:
    >
    > In the previous email I neglected to give the spread in the loci - Y
    > has a range of 0.7 mag in the new search, but only 0.3 mag in the 2003
    > search. That is objects at the same magnitude in the new search have a
    > variation in S/N of about a factor of 2. So, the reason this
    > observation may matter is that it suggests a rather large variation in
    > depth amongst the various images in the new search.
    >
    > This should be straightforward to check, and of course Rob may have a
    > quick explaination.

    The aperture thing I was mentioning last time -- first time around, I
    was using a "way too big" aperture. There, the S/N would have been less
    sensitive to variations in the aperture size. (It would also have been
    lower.) Later during the process (by the acs02-03c subtractions), the
    aperture was smaller, but I think most candidates had been found by
    then.

    -Rob

    -- 
    --Prof. Robert Knop
      Department of Physics & Astronomy, Vanderbilt University
      robert.a.knop@vanderbilt.edu
    


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