From: Serena Nobili (serena@physto.se)
Date: Tue Jan 06 2004 - 08:50:44 PST
Dear Saul,
thank you for your comments, and I have to admit, it was fun to hear them
coming directly from your voice. Apart from the corrections to the
language, missing refs and similar, you pointed out issues, some of which
were pointed out also by others, that as you suggest, is probably
better to discuss by phone rather than in very long e-mails.
As I am leaving for Paris this Sunday, I would suggest to
have a first quick run already Thursday this week, perhaps with the exec
only or with the most people we can gather and then have a larger one with
the whole collaboration next week. I wait to hear your decision.
Cheers
Serena
Meanwhile, let me give you some short answers or comments to use as input
for the discussion.
1) You say that I get a larger dispersion in the I-band peak than
Lifan. How much larger? Also this depends critically on which SNe are
included, especially given the differences between the different data set.
What I found, is consistent with Hamuy (1996) once the 6 SNe of the CfA
set are excluded. Another point to consider is that reducing the
dispersion on the nearby sample will make the high-z SNe even more
deviating, their dispersion being already quite large. So unless we are
really sure about it, and differences are relevant, I would not like
to touch those numbers.
2) About the Monte-Carlo simulation on the high-z SNe lightcurve fits.
I say "wrong" in the paper, when in section 4.5 I say: "this was found to
be robust, always selecting the same template as the one giving the best
fit for all the three supernovae". This is true for SN 2000fr (aka
Beethoven), and it is almost true for SN 1999ff where 99.5% of the
times (out of 1000 simulations) I get the best fit template. For SN
1999Q this happens 94.2% of the time. See discussion and plot in the paper
web page:
http://www.physto.se/~snova/internal/papers/iband/#hizfit
Even so, I think it is still impressive how so few data points can
constrain the template so well.
3) About the 2 nearby SNe which I do not correct for host galaxy
extinction (98es & 99dq). To understand why I got to this conclusion, see
the plots in:
http://www.physto.se/~snova/internal/papers/iband/#hgext
4) About the estimated systematic uncertainties on the high-z SNe, I agree
with you that it could be not the optimal way of estimating it, but it is
the best we have. Look at discussions and plots in:
http://www.physto.se/~snova/internal/papers/iband/#hizsys
5) the plot of sB vs sI, that you were wondering whether to add or not in
the paper:
http://www.physto.se/~snova/internal/papers/iband/figs/select.comp_ib.ps
(these are many plots about other correlations I tried to look at)
6) Spectral templates. You point this out in a couple of situations.
Differences in the estimated K-corrections from J to I, using my templates
and Rob's templates at z~0.5 are about 0.05 mag, see the document written
by Chris Lidman and available at his web page:
http://www.sc.eso.org/~clidman/kcorr.ps
In section 6 instead you ask whether our different methods agreed on this.
I interpret this again about the study on colors made by both Rob and me.
I am afraid Rob did not carry out studies on correlations. So I have
to assume mine are the correct ones :-)
7) About 1999Q. The B-band data are not available from anywhere. In Tonry
et al 2003 this is used in the Hubble diagram and they give the luminosity
distance, but no information on Dm15. (See also the email I sent to Greg
yesterday about it)
On Mon, 5 Jan 2004, Saul Perlmutter wrote:
>Hi Serena,
> Here are my comments (scanned in PDF format, and explained in the
>MP3 voice recording, since the scan is probably not obvious by
>itself). First and foremost, I think this is very interesting work --
>nice going! (...which I didn't remember to say in the midst of all the
>detailed comments in the voice recording!)
>
> There are a number of points that I think will be good for the
>collaboration to discuss together (and give you a bit of help with some
>of the work, ideally) -- probably we will want to have a collab phone
>conference like we did with Rob's paper. We'll try to plan that this
>week in the exec meeting.
>
> Talk to you soon, and happy 2004. --Saul
>
------------------------------------------------------------------------ www.physto.se/~serena Tel +46 8 55378661
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