Re: question for HST paper

From: Andy Howell (DAHowell@lbl.gov)
Date: Wed Apr 30 2003 - 19:44:07 PDT

  • Next message: Greg Aldering: "Re: question for HST paper"

    Greg,
    This mainly a psychological effect of the rebinning -- I rebinned the
    data to 20A.
    I put up on the web page the same plot rebinned to 3A -- you can see it
    looks like the
    untouched data.

    Also, the spectrum I show is cropped to only show where the template
    spectrum and
    the observation overlap. I put up another plot showing a different fit
    with more of the data.

    My program has the freedom to do other things to the data as well. In
    my plots I have alread
    subtracted host galaxy. Plus, my program either reddens or bluens the
    spectrum to find the best fit.

    So the spectrum I show may not correspond to reality -- I let it mangle
    the observed
    spectrum to find the best fit possible. Often it will find junk, but
    the point is that
    if there is a Ia signal there it should find it. Here I just chose one
    example to show,
    but I don't believe it -- I don't believe any of the fits.

    -Andy

    Greg Aldering wrote:

    >Hi Andy,
    >
    >I am looking at the spectral fits to 98104 on your website. I don't see a
    >relation between your spectrum and Isobel's. Am I even looking at the
    >right thing? (Yours is labeled "Observed: 98104cc_comb.Ic.asc" and
    >Isobel's is labeled "98104 (Keck) : 98104cc_comb.asc". Yours is a
    >power law and Isobel's have plenty of wriggles.
    >
    >
    >
    >>Due to the E's 4000A break, you subtrack off more light blueward of 4000A
    >>than redward, and this can mimic Ca from the SN.
    >>
    >>
    >
    >No. The effect of subtracting an elliptical is to decrease the strength
    >of Ca - unless you let the elliptical go negative! But I do agree that
    >9878 isn't convincing.
    >
    >- Greg
    >
    >
    >

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