Re: slides for today

From: Reynald Pain (reynald.pain@in2p3.fr)
Date: Mon Mar 14 2005 - 08:48:55 PST

  • Next message: Tony Spadafora: "SCP Paper II: CMAGIC Cosmology analysis. Comment by 4/1/05."

    Hi Alex,

    Thanks!
    (concerning the "insensitive/sensitive" remark. that was my
    mistake/misreading...)
    Cheers,
    Reynald

    Le 9 mars 05, à 23:36, Alexander Conley a écrit :

    > Hi Reynald,
    >
    > Thanks for your comments. Sorry it's taken so long to respond;
    > I have been busy applying for a Canadian Work Permit and the like.
    >
    > I have put a new version on the webpage (version 1.52) reflecting
    > your suggestions. See below for details -- including some questions
    > of clarification that I have for you.
    >
    > Alex
    >
    >> The sentence "disagree .. at 1.7 sigma" sounds odd : disagree is a
    >> strong statement , 1.7 sigma is not much.
    >> also the "favors ... at 1.6 sigma"
    >> do the sigmas even include (known) systematics ?
    >>
    >> for the 2nd statement I would say the CMAGIC and peak mag agree
    >> within less than 2 sigma (I assume that this sigma is
    >> not the statistical sigma of one of the method or any combination of
    >> the two since the two measurement are done with the same data. you
    >> took that into account right ?
    >
    > I agree, it isn't totally obvious what to say here. Perhaps the more
    > neutral
    > 'differs from a flat universe'. I'm not completely comfortable saying
    > agrees at less than 2 sigma, since 2 sigma isn't totally negligible,
    > but you are correct that disagree is a stronger statement than 1.7
    > sigma
    > warrants.
    >
    > The numbers include systematics, and correlations, and the abstract
    > now reflects this.
    >
    >> page 2 : 3rd paragraph : I think the stretch was introduced in P97
    >
    > Included
    >
    >> page 3 : 3rd paragraph : add ref Tonry03 and Barris04 who also use (I
    >> think) the Bayesian approach to treat extinction ?
    >
    > Added
    >
    >> page 3 paragaph 4: you say that CMAGIC has advantages for evolution
    >> but do not clearly say what the benefit is.
    >
    > Modified to say 'and possibly evolution, depending on the model.'
    >
    >> page 5 : "By studying well observed ..; " explain how
    >
    > The real details are tedious and inappropriate to include, but I have
    > added the text
    >
    > 'Using well observed low redshift SNe to
    > determine the earliest and latest points in the linear region as a
    > function
    > of stretch, we find that beginning date of the linear region is ...'
    >
    >> page 9 : top : "0.1 rest frame days" why not .1 and not 0.5, 1,
    >> ... ? justify specially if the analysis is very sensitive to it
    >
    > Uh, the same sentence says that 'the analysis is quite insensitive to
    > this
    > value'. More specifically, it can range from 0.1 to 7 without having
    > any
    > difference at all. Are you saying that I should simply remove this
    > sentence?
    > (However, that should have read 0.5 days).
    >
    >> page 17 : last paragraphe before 6.4 . i ma not sure the first 2
    >> sentences are needed
    >
    > Experience suggests that people do ask how well the secret
    > offset worked, so it seemed worth including.
    >
    >> systematics: Include some estimate of systematics from K-cor (other
    >> than U-enhanced) (propagate uncertainties of K-corr
    >
    > I would love to have a better handle on the kcorr systematic. What do
    > you
    > suggest?
    >
    > If you are saying to do what Rob, Riess, etc. do, which is to add
    > around 0.02
    > mag uncertainty to each magnitude, this isn't a systematic. In fact,
    > it's totally
    > useless even as a statistical error, since it is already included
    > automatically
    > in \sgi .
    >
    >
    >> Conclusion : same remark as for the abstract concerning the
    >> conclusions drawn from 1.6 and 1.7 sigma deviations
    >
    > Again toned down slightly.
    >
    >> acknowledgments : I did not find 1999ee in the list of SNe you use.
    >
    > Yes... This raises an interesting point. 99ee was not present in the
    > primary fit, but was used in some of the systematics tests
    > (specifically,
    > when the extinction correction was weakened). So I would rather not
    > include it in the list of data, but I did use it and feel like I
    > should thank
    > those who provided it. I will add some text to the acknowledgements
    > reflecting this.
    >
    >> fig 4 : what about using a smaller binning (half size or even of 0.05
    >> mag)
    >
    > I played around with lots of binnings, and cutting the bins in half
    > introduces a lot of noise. The highest bins get down to 8 events, so
    > aren't too bad, but the flanks become hard to read.
    >
    >>
    >> fig 7 : do not show the marginalized distrib ?
    >
    > I personally agree with you, but am waiting to see what other
    > people think before I remove it.
    >
    >> fig 9: in the caption give the value of alpha found
    >>
    > Okay.
    >
    >
    >
    ___
    reynald.pain@in2p3.fr
    LPNHE, University Paris VI & VII, 4 Place Jussieu, 75252 Paris Cedex 05
    Tel: +33 1 44 27 72 53 - Fax: +33 1 44 27 46 38 - LBL: +1 510 495 2595



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