From: Gabriele Garavini (garavini@in2p3.fr)
Date: Wed Feb 23 2005 - 05:03:04 PST
Hi Handy,
thanks for your comment.
I'll implement them soon.
For the host Galaxy issue as I think is clearly stated in the paper the
galaxy subtraction was done using Gregory's code, not yours (but in some
sense his is similar to your, it has a different minimization procedure
and parametrization). I know that this kind of codes might have a
problem with the estimate of the galaxy subtraction so I asked Gregory to
make a small Montecarlo to check the consistency and uncertainty on the
Galaxy subtraction. So he added some percentage of galaxy to some not
contaminated spectra and run the software, he reported a 10% of
uncertainties on the host galaxy contamination computed. The 10% I
considered in both directions as possible systematic on galaxy
subtraction. It might not be clear in the text, but of course the 10% is
+- 10%. I'll make sure to spell this out in the new draft.
For the Ia-Pec, I'm not claiming this is the first Pec high redshift
spectrum published (even if it was the first one discovered, but we know
how these things go) but I do think is interesting to point out that there
is a peculiar and that we can tell also from the CaHK EW. I do not think
the paper makes a big thing out of it.
Thanks you very much
Cheers
Gabriele
>
> Start of Andy's comments
> ========================
>
> Comment #1
>
> The largest source of uncertainty is the host galaxy subtraction. Yet
> this is swept under the rug. If this was done using the determination
> from my program, for example, you can't trust any of the conclusions
> from the paper. My program simultaneously fits host galaxy and SN
> templates. In other words, it *assumes* that the high-z spectra is
> similar to a low-z one and subtracts an amount of host light such that
> the high-z and low-z spectra will look similar. The proper thing to do
> would be to use the photometry (e.g. percent increase) to constrain the
> amount of host galaxy light, and to use imaging and spectral features to
> constrain the host characteristics. You might be able to say some
> spectrum has 30% host +/- 10%, and is either an E, SO, or Sa. Then you
> could do different subtractions in that parameter space and test the
> results. Defining a technique like this would be a great addition to
> this paper because any time people use high-z spectra they are going to
> have to do something like this.
>
> Comment #2
> ==========
>
> One other point -- in the SNLS we have many 91T/99aa SNe at high
> redshift. So there is no need to make a big deal out of having one in
> the sample, as this paper does.
>
> Minor comments
> ==============
>
> p. 1
> Intro, par. 1 -- plural of supernova is supernovae
> tidly ????
> par. 4 it should be pointed out that the effect metallicity has
> on the spectrum pointed out by Hoeflich and Lentz are only for
> early-time
> spectra, of which there aren't many here.
>
> par. 6 -- I have submitted a paper on SNLS gemini spectra -- Howell et
> al.
> 2005, ApJ, submitted
>
> p. 2, section 2.1 last sentence, One SNe -> One supernova
>
> last paragraph of section -- two days is no longer the uncertainty for
> the
> spectroscopic epoch determination in Hook et al.
>
> section 2.3, par 1 -- you say EWS but it is not defined yet.
>
> p. 4
> table 2 'Si' should be 'Si 4000' since you say it is absent in
> underluminous SNe.
>
> first paragraph on page - there is a period missing before SN 2002fd
>
> p. 5
> 3.1, 3rd par. "uncertainty in the redshifts is taken to be 300 km/s if
> the
> redshift was estimated from galaxy lines..."
> shouldn't this be proportional to the redshift?
>
> 3.2 first sentence -- delete ", they" and second comma.
>
> p. 6
> "possible involved" delete involved
>
> p. 7 last par in 3.2.1 delete space in "spectra ,"
>
> 3.2.3, 4th par -- delete space: "( with"
>
> p. 8 3.3 miss-identification -> misidentification
> this whole parenthetical expression should be made into a new sentence
> because it is confusing with "uncertainties" written twice in a row.
>
>
>
> On Tue, 2005-02-22 at 05:24, Gabriele Garavini wrote:
> > I'm very sorry chris I sent by mistake the wrong file.
> > Here is the one I meant to send.
> > Thanks
> > Gabriele
> >
> > On Mon, 21 Feb 2005, Chris Lidman wrote:
> >
> > > Hi Gabriele,
> > > Could you resend the attachment. The one I received seems to be
> > > chopped at the end.
> > >
> > > Regards,
> > >
> > > Chris.
> > >
> > > On Mon, 2005-02-21 at 13:29, Gabriele Garavini wrote:
> > > > Dear Chris
> > > >
> > > > thanks you very much for the careful reading of the paper. I've
> > > > implements most of you comments. Please find all my answers in the
> > > > attached file. I also changed extensively the section about EW (3.2) I
> > > > hope this will allow us to go to submission shortly.
> > > >
> > > > Thanks again
> > > > Hasta la vista.
> > > > Cheers
> > > > Gabriele
> > >
> > >
> > >
>
>
>
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