Re: HST paper - high-redshift stretch-luminosity relation

From: Ariel Goobar (ariel@physto.se)
Date: Sun Apr 27 2003 - 06:54:52 PDT

  • Next message: Alex Kim: "Re: HST paper - high-redshift stretch-luminosity relation"

    On Sat, 26 Apr 2003, Greg Aldering wrote:
    Hi Greg,
    can you please provide the chisquare for the high-z data w.r.t
    1) the solid line 2) the no correlation case?
    Thanks,
     Ariel
    >
    > 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
    > 

    -- 
___________________________________________________________________
Ariel Goobar (www.physto.se/~ariel)
Department of Physics, Stockholm University
AlbaNova University Center, SE-106 91 Stockholm, SWEDEN
tel: +46 8 55378659 fax: +46 8 55378601

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