From: Alexander Conley (ajconley@lbl.gov)
Date: Wed Mar 09 2005 - 14:36:36 PST
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.
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