HST paper - high-redshift stretch-luminosity relation

From: Greg Aldering (aldering@panisse.lbl.gov)
Date: Sat Apr 26 2003 - 22:56:29 PDT

  • Next message: Ariel Goobar: "Re: HST paper - high-redshift stretch-luminosity relation"

    For those following the progress of the HST paper, at the last telecon it
    was suggested to Rob that the stretch-luminosity relation for our
    high-redshift SNe be shown since the stretch and peak magnitudes are
    well-measured with HST. Rob is away this weekend, and since the
    stretch-luminosity relation is an obvious thing to examine in the context
    of supernova evolution (which Lifan and I are working on), I decided to
    take a crack at making such a plot in the interests of making progress on
    the paper.

    I used the lightcurve fit parameter tables in the paper, along with
    cosmology fit residuals supplied by Rob and the values of alpha given in
    the paper, to undo the stretch correction that Rob applied when performing
    the cosmology fits. I have attached postscript plots showing the
    stretch-lumnosity relation of our HST SNe, superimposed on that for the
    Hamuy SNe, for your consideration. The first plot uses the SN data without
    extinction correction, while the second plot shows the results after
    extinction correction. The solid symbols are our HST SNe, while the open
    symbols are the low-redshift SNe.

    Note that (to my knowledge) we have never published a stretch-luminosity
    relation! Those of you who have never made such a plot for yourself might
    be surprised that the extinction-corrected relation for the low-redshift
    SNe is not prettier. However, the deviations you see here are common to
    the various stretch analyses I have seen. You also see that there is no
    convincing relation at all for the high-redshift SNe by themselves. Note
    however that the high-redshift SNe clearly populate the same parts of the
    diagram, including tracking some of the systematic deviations, as the
    low-redshift SNe. (Of course the deviations for the high-redshift SNe are
    not as significant as those for the low-redshift SNe because the error
    bars are larger.) If we put one or both of these plots in the paper, I
    think it would at least show that the low- and high-redshift datasets are
    similar in their stretch-luminosity behavior.

    I would be interested in people's reaction to including such a plot in the
    paper.

    Cheers,

    Greg


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