From: Gabriele Garavini (garavini@in2p3.fr)
Date: Tue Aug 24 2004 - 06:09:15 PDT
Dear Chris,
thanks a lot for your comments. I'll implement them as soon as possible.
In the meanwhile I'd like to discuss few points. In the following I make
few remarks on the issues you pointed out.
Cheers
Gabriele
> Hi Gebriele,
> I've read through the July 13th version of the paper and I provide
> you with some comments.
>
> Some results from recent analysis
> =================================
>
> - Rob is currently updating the light curve fits for all the T02 SNe Ia
> and some of the S01 SNe Ia. I suggest you contact him to get the latest
> fits. This will enable you to get accurate dates for each spectrum and
> to shrink the horizontal error bars in Fig. 5. Indeed, I believe that
> you should use the light curve dates whenever possible.
I'll certainly do that.
> - You might want to add SN 2002gj (T02-028) to the paper. From the
> spectrum, we classified this as a Ia*. If one uses the lightcurve
> to set the epoch at which the spectrum was taken, it is very likely
> that it is a Ia.
>
> Section 2.2
> ===========
>
> - The VLT paper has been revised considerably and there is now an
> extensive discussion on how we classify candidates. I also expect that
> there will be a similar discussion in Isobel's paper. Hence, I
> think that you should revise section 2.2 with these two papers in mind.
> My personal preference is that you shorten this section considerably
> and
> that you refer the reader to Isobel's paper and to the VLT paper if
> they want to learn how we classify candidates.
I do agree with you, this could be removed. Let me read your final
version
and based on that I'll reshape this section.
> - I do not think that figures 1a, 1b and 1c add anything to the paper.
> The spectra are already displayed in the VLT paper. I suggest that
> these
> figures are removed.
I do not see why showing again in this paper the data we use for the
analysis should be a problem. Besides I think it makes easier for the
reader to check out the spectrum where the measurement has been done
without having to go to the other paper.
> - Table 1. The order of the SNe is eratic. I suggest that you order
> them
> according to the SN name.
Actually they are ordered according to the epochs. I should point that
out
in the caption.
> - The +5.6 day spectrum of SN 2001go is not the highest S/N spectrum. I
> believe that the +9 day spectrum is.
I'll double check this. I'm quoting the S/N for 20 A bin.
> - The +9.5 and +29.5 day spectra of SN 2001go are not presented in the
> VLT paper. I think it would be worth having a separate section on this
> SN in the paper. It would be good if we could produce a plot which
> shows
> how this SNe can be matched at each epoch.
I'm not sure I understand what you mean with: "plot which shows
how this SNe can be matched at each epoch". Would you like me to add a
section with comparison plots for each epoch bin?
> Section 2.3
> ===========
>
> - What is the age bias? This is not clar to me. Perhaps this could be
> explained in more detail.
This is explained in Li et al 2001b. I'll anyway add a note in the text.
> - The Hubble flow starts at z=0.01 or z=0.015. Are there no other
> 91T/99aa like Ia SNe in the Hubble flow?
I believe formally at z=0.015
> Section 2.3
> ===========
>
> - Do you want me to remove the telluric features in SN 2002fd?
I do not think is necessary.
> - Note that Eric might have found a 91T-like SNe at an even higher
> redshift.
I'm sure there are. But none has been published yet (as far as I know)
> Section 3.1
> ============
>
> - SNe 2002fd, 2001gw, 2002hc, 2002gk and possibly 2002km (not in your
> sample) have SiII at 6150. Are five SNe enough to measure the SiII
> velocity and to produce a plot that is similar to the one you have done
> for CaII.
I'll see what I can measure.
> Section 3.3
> ===========
>
> - If you were to compare the mean values of the MgII feature for the
> low and high redshift samples, I think that you would find that the
> difference between the low and high redshift samples is statistcally
> significant. If this is the case, this should be highlighted in the
> abstract.
I believe table 3 tells us that indeed the fit is not that good, thus I
do
think the mean value would show some difference. However I would not
make
a big deal out of it. I'm more inclined to think that is due to a
residual
of the galaxy subtraction. What we can say is that the measurements are
still comparable with does of normals and that do not show values
typical
to underluminos. I do point out this also in section 3.2.
> - Lentz models. From this paragraph, I understand that we see a larger
> variation than they do. We may find a larger variation because of
> unidentified systematic or statistical errors.
We do take into account the possible statistical error in this analysis
but indeed we do not have full control over the systematics. However,
the
Lentz models can not be considered the full story concerning possible
metallicity effects on SN spectra. Anyway the difference in intrinsic
spread between the models and the local data is at least an order of
magnitude if I recall correctly. We do not expect to have such a
systematic uncertainties (see Gaston's paper)
> Overall
> =======
>
> At this point in time, I think that the paper might be better published
> as a letter, since it is presenting an analysis which has never been
> done before.
I'm open to (almost) any form of publication as long as it happens fast.
> Cheers, Chris.
>
>
>
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