From: Chris Lidman (clidman@eso.org)
Date: Mon Jan 31 2005 - 15:13:10 PST
Hi Serena,
Here are my comments on the latest draft. As you will see, I'm about
half way through the paper and I am concentrating on the wording. Nearly
all my comments are suggestions on how the text could be made clearer.
I'll go through the second half tomorrow.
Cheers, Chris.
-- European Southern Observatory Alonso de Córdova 3107, Vitacura Casilla 19001, Santiago 19 CHILEPh. +56 2 463 3106 FAX +56 2 463 3001
General Comments
================
Capitalise the 't" in "type Ia supernova", i.e. "Type Ia supernova"
local/nearby SNe Ia - I think that you use both adjectives. Choose one.
Abstract
========
The first acronym - SNe. Should this be SNe~Ia, as we usually write in SCP
publications?
Section 1. Introduction
=======================
1st paragraph
The first acronym (SNe) is already defined in the abstract.
restframe B-band -> the restframe B-band
a concordance universe (...) -> a universe in which (...), which is commonly
referred to as the concordance universe.
SN Hubble diagram -> SN~Ia Hubble diagram (perhaps you need to be more
specific here)
2nd paragraph
sensitivity to -> extinction by
3rd paragraph
This paragraph may not be clear to everyone. I guess that you would like to
say that the error in I-band extinction corrections are much less than
those in the B-band. If this is the case, I suggest that you rephrase the
first sentence.
Using restframe I-band ... -> In the restframe I-band, the uncertainties in
the extinction correction are much less than those in the B-band.
4th paragraph
I-band light curves -> SNe Ia I-band light curves
5th paragraph
restframe I-band -> the restframe I-band
assess the importance -> to assess the untily (or usefuleness)
I light curve -> I-band light curve
Move the non-restrictive clause "which we apply to 42 nearby SNe Ia" to the
end of the word "technique". I.e. "... technique, which we apply to 42 nearby
SNe_Ia, to measure ..."
"We use the fitted I_max of 26 of these SNe Ia, which are in the
Hubble flow, together ..."
6th paragraph
Is it necessary to mention Riess and the problems with 99Q at this point?
Section 2 I-band light curve fitting
====================================
1st paragraph
single parameterised -> singly parameterised
"currently often" -> "currently" (I do not think the word often is necessary)
2nd paragraph
"In this way is ..." -> "In this way, it is ..."
"does not" -> "it does not"
"their method for our purpose, is" -> "their method, for our purpose, is" (an
extra comma)
Replace "that ... sampled" with "very well sampled light curves."
4th paragraph
I suggest a small amount of rewording and re-organisation in this paragraph.
For the first sentence, I suggest
"The use of this function in place of the function described in
Contardo et al. (2000) reduces the number of fitted parameters by a
factor of two."
The second sentence is then no longer necessary.
Then, we can remove the footnote and add
"We choose to use the B-band template of Nugent et al. (2000) as the
template to describe both peaks. Other choises for the template might
be better; however, we find the B-band template to be adequate.
and modify the next sentence so that
"in (the) I-band is the same as in the template used." becomes "is the
same in the I- and B-bands."
"optimal" -> "true"
Section 2.1
===========
local SNe -> local SNe Ia
comes -> come
"least" - If the reader sees this word, he might think that other data
sets are available, and he might wonder why we did not use them. Perhaps,
it is better to say, "We have used two data sets ..."
"days, another one," -> "days, and another"
Section 2.2
===========
1st paragraph
"covering in time constraining" -> a coverage in time constraining"
poissonian -> Poissonian
table ??
2nd paragraph
"as in (Kim ..." -> as in Kim et al. (1996) and Nugent et al. (2002).
K-corrections -> k-corrections (It is up to you to choose, but I prefer
the latter)
systematic uncertainties -> systematic uncertainty
"for increasing redshift" - By adding the clause, the reader may think that
the dispersion increases with redshift. Is this true? Perhaps, this
phrase can be deleted.
4th paragraph
"B-band maximum" -> "the B-band maximum"
"for the underluminous supernovae" -> of underluminous supernovae"
5th paragraph
1986G -> SN 1986G
"do not show a different behaviour ... SNe. -> do not have peculiar IR
light curves.
"to assess a greater homogeneity" -> "to assess the utility (or usefulness)"
7th paragraph
"the fitting template" -> "our model"
"We note ... would fail to fit the rest of the sample." I think that
the point here is that these 6 SNe Ia will always be outliers, no matter
which template is chosen, since any template which is chosen to fit
the other six SNe will never be able to fit these SNe.
Section 2.3
===========
Paragraph 2.
The first sentence could be rephrased.
In two cases, SN 1997br and SN 1998ab, we found that the fits to the MC
simulations resulted in two solutions, one corresponding to that found
in the fit to the real data and the other corresponding to a small
fraction (3\% and 22\% for SN 1997br and SN 1998ab respectively) of
all simulations.
I don't think that we can argue that the MC simulations have failed. Perhaps
it is the fitting that has failed - i.e. a false minimum was chosen.
Perhaps, it would be better if we did not go into too much detail. It might
be better to delete 3rd and 4th sentences in this paragraph.
When I saw the following in the last sentence, I became confused.
"estimating the parameters and their uncertainties from the main distribution."
Do you estimate the uncertainties in the parameters from the fit to
the real data or from the fits to the MC simulations? From this
clause, one would assume the latter. Or, is the latter method only
used for SN 1997br and SN 1998ab?
Section 2.4
===========
1st paragraph
The second sentence could be rephrased to
Following Goldhaber et al. (2001), the time of maximum, the stretch
factor (s_B) and the peak magnitude (m_B) were determined by fitting a
B-band template to the published B-band data.
"for peculiar" -> "for the peculiar"
corrections -> correction
"from average" -> "from the average"
In reality, you are excluding 3 SNe in figure 3, SN 1998es, SN 1999dq and
SN 1995E. To make this clear for the rest of the article, perhaps you
can change the sentence discussing SN 1995E to
"At this point, we exclude SN 1995E from the sample as it is highly
reddened. It is not shown in any of the plots nor is it used in any of
the analyses that follow."
The dispersion measured ... line is" -> The dispersion, computed as the r.m.s
about the fitted line, is"
"stretch in I-band" -> "stretch in the I-band"
"with an r.m.s of ~ 0.19 mag, about" -> "with a r.m.s of ~0.19 mag about"
(note the removal of the coma).
remove the word "obtained"
2nd Paragraph
"also" -> "that are"
remove the comma between peculiar and behave.
The last sentence in this paragraph seems lonely. Perhaps it would feel
better if you move it to the caption and change it to "The straight
line is a fit to the data excluding the labeled SNe."
3rd Paragraph
"and Galaxy and host galaxy extinction" -> "and for extinction from the host
and the Galaxy".
5th paragraph
"B-band stretch" -> "the B-band stretch"
"peculiars" -> "peculiar"
"are two standard deviations away from the rest of the sample." ->
"are more than two standard deviations from the straight line fit."
Figure 1.
=========
In the caption to the lightcurve fits of SN 1991bg and SN 1997cn.
"is fitted as ~3 mag" -> "is ~3 mag. fainter"
Figure 3.
=========
"stretch in B-band" -> "the stretch in the B-band"
"best fit" -> "best straight-line fit"
Figure 5.
=========
"in B-band" -> "in the B-band"
"supernovae labelled" -> "labelled supernovae"
Figure 6.
========
There are other SNe which seem to be more that 2 sigma away from the
best straight line fit, but none of these are marked in any special
way.
Table 3
=======
"CMB frame" -> "the CMB frame"
"the dust extinction" -> "dust extinction"
Section 3
=========
1st paragraph.
"don not dominate the trend." -> "do not dominate the errors."
Paragraph 3.
As a note, an alternative way of estimating the instrinsic uncertainty
is to add a magnitude error in quadrature to each SNe and to repeat the
fit until the reduced chi-sq. is one.
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