Re: SCanning and such update

From: Rachel A. Gibbons (ragibbons@lbl.gov)
Date: Sat May 22 2004 - 17:21:34 PDT

  • Next message: Rachel A. Gibbons: "Re: coordinates"

    Vitaliy,

        OK. So this answers my previous e-mail. We'll look into this and all
    the candidates after we're back to the office late tonight. I suggest
    moving on.

    Rachel

    On Sat, 22 May 2004, Vitaliy Fadeyev wrote:

    >
    > I meant the real objects -- galaxies and such. They subtract nicely on
    > other tiles,
    > but not on acs04maysub-i/norm01i.
    >
    > vitaliy
    >
    >
    > Robert A. Knop Jr. wrote:
    >
    > >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
    > >>
    > >>
    > >>
    > >>
    > >>
    > >
    > >
    > >
    >
    >
    >

    -- 
    ------------------------------
    Dr. R. A. Gibbons
    Lawrence Berkeley National Lab
    1 Cyclotron Rd MS 50R5032
    Berkeley, CA 94720-8160
    USA
    Tel 510.486.7416
    ------------------------------
    


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