Re: HELP NEEDED

From: Natalia Kuznetsova (nvkuznetsova@lbl.gov)
Date: Sat Apr 03 2004 - 20:05:43 PST

  • Next message: Vitaliy Fadeyev: "Re: HELP NEEDED"

    Hi Vitaliy,

    For sub04mar/mar172004suprimeb28956sum.fts and GOODS field 24, I get the
    average ratio of Subaru to GOODS fluxes of 51900.

    For sub04mar/mar172004suprimef28956sum.fts and GOODS field 34, I get the
    average ratio of Subaru to GOODS fluxes of 40688.

    Natalia

    Vitaliy Fadeyev wrote:

    >Rob,
    >
    >Natalia, Lifan and I are going to do this now.
    >
    >vitaliy
    >
    >
    >
    >"Robert A. Knop Jr." wrote:
    >
    >
    >
    >>At some point (probably not until late late tonight) Subaru I-band
    >>subtractions will start showing up.
    >>
    >>These are the zeropoints that will be used for them:
    >>
    >> sub04mar/mar172004suprimea28956sum.fts | 38.1048017998
    >> sub04mar/mar172004suprimeb28956sum.fts | 38.1206147516
    >> sub04mar/mar172004suprimec28956sum.fts | 37.131587848
    >> sub04mar/mar172004suprimed28956sum.fts | 36.8684151492
    >> sub04mar/mar172004suprimef28956sum.fts | 37.7517776011
    >> sub04mar/mar172004suprimee28956sum.fts | 37.5677277862
    >> sub04mar/mar172004suprimeg28956sum.fts | 37.3110273633
    >> sub04mar/mar172004suprimeh28956sum.fts | 37.2026060372
    >> sub04mar/mar172004suprimei28956sum.fts | 37.5857562505
    >> sub04mar/mar172004suprimej28956sum.fts | 36.4820993053
    >> ^
    >> |
    >>
    >>The indicated letter is the chip of the subtraction.
    >>
    >>These zeropoints are completely bogus. (They are based on the R
    >>magnitudes from the USNO catalog and should not be trusted to better
    >>than a magnitude or two.) I need somebody to figure out a reasonable
    >>zeropoint for these images. At that point, we will need to adjust any
    >>magnitudes that come off of the Subaru subtractions by the *difference*
    >>between this zeropoint and the real zeropoint determined for these
    >>images.
    >>
    >>These are I-band images. You can get at them with
    >>
    >> finddbfile -g <filename>
    >>
    >>or
    >>
    >> imview -scp <filename>
    >>
    >>Note that the night was decidedly not photometric, so just taking a
    >>published Suprime-Cam zeropoint won't work. (Plus, I'm not sure about
    >>the units of this sum.) We have to do something empirical to get a
    >>vega-based zeropoint for these imgaes. Perhaps match and compare to
    >>GODOS images (whose zeropoints *should* be good), or perhaps match and
    >>compare to pre-existing calibrated data.
    >>
    >>This will be a painful hand-work task, and I don't have time to do it.
    >>
    >>The same may eventually need to be done for the subaru z-band images.
    >>
    >>-Rob
    >>
    >>--
    >>--Prof. Robert Knop
    >> Department of Physics & Astronomy, Vanderbilt University
    >> robert.a.knop@vanderbilt.edu
    >>
    >>
    >
    >
    > 

    -- 
______________________
Natalia Kuznetsova
Lawrence Berkeley National Laboratory
1 Cyclotron Road, MS 50R5032
Berkeley, CA 94720-8164
Tel: (510) 486-4877
FAX: (510) 486-7115
______________________

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