Equivalent Width measures

From: Robert A. Knop Jr. (robert.a.knop@vanderbilt.edu)
Date: Tue Dec 21 2004 - 13:55:59 PST

  • Next message: Gabriele Garavini: "Re: Equivalent Width measures"

    Eric (and others) --

    A summary of the discussion at the phone meeting.

     * It turns out that the way you've been measuring the endpoints is
       different from what Gaston and Gabriele have been done.

       The fact that we've proven it unclear makes it obvious that the brief
       description in Gaston's paper is insufficient, and needs to be
       clarified and properly specified (ideally in Gabriele's paper, if
       that's the next thing that will be published on this stuff). That's
       the first important point.

       The second point is that Eric, you need to make sure that you can
       reproduce what's done using the actual method. What is done is that
       a small region around the maximum on either side of the "line" is
       chosen. Data points within those two small regions are *together*
       fit into a single line, which defines the continuum. (QUESTION FOR
       GABRIELE AND GASTON: WHERE ARE THE "ENDPOINTS" DEFINED FOR THE LINE
       FLUX? I didn't get that out of our discussion, and it's not defined
       in the paper.)

     * Needed from Gaston ASAP (certainly by January 1):

            1. The equivalent widths he gets for individual supernovae

            2. The actual spectra used, in cases where galaxies were
               subtracted

            3. description of prescription for defining the continuum
               (though I think I understand that, except that it's not clear
               how you choose the size of the region around the maximum, and
               *SOME* sort of prescription or at least guildlines need to be
               given for that)

            4. description of prescription for choosing the endpoint
               wavelengths over which to integrate.

     * Eric: when you get back, first make sure you can reproduce Gaston's
       numbers using his method for defining the continuum and endpoints.
       Next, repeat your noise-adding, smoothing, and binning simulations
       using the new prescription to see if the systematics go away, or what
       happens with that.

     * The goal is to have all of this done by the second week of classes,
       before labs start again at Vanderbilt.

    -Rob

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


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