From: Isobel Hook (imh@astro.ox.ac.uk)
Date: Sat Jan 03 2004 - 10:46:50 PST
Hi Serena,
I think the draft looks very good, well done! Here are some comments -
most of these are just details where I am being very picky!
Cheers,
Isobel.
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Intro:
I see that there is a new paper on very low-z I-band light curves by
Krisciunas, Philipps and Suntzeff (astro-ph/0312626) which you could
mention.
Section 2:
At the start of this section I think it's a bit misleading to say that
B and V-band lightcurves have been fit with a ONE-parameter template -
really it's a 3-parameter fit: tmax, Bmax, stretch (or dm15). If you
are going to say you use 5 parameters in your I-band fit then you
should be consistent and include tmax and peak-flux as parameters when
you talk about B-band fitting.
Later in this section you say that using a B-band template reduces the
number of free parameters by a factor 2 compared to the method used by
Contardo et al. This is sort of true but the template is an emprical
one derived from a lot of real data points - you could almost say it
had an infinte number of free parameters which had to be constrained
by hundreds of nearby measurements. So it's not as magical as it
sounds!
Organisation : I suggest you move the first two paragrpahs of section
2.2 into the first sub-section of section 2 (or make a new subsection
called "Fitting method"). At the moment much of the section on
"fitting results" is really about the fitting method.
I dont really understand why the Ca IR triplet should cause problems
at any z provided the filters are a good match to whatever rest-frame
band you're aiming for. I think that paragraph needs explanation or
remove it.
Section 2.4: "A width luminosity relation was found for the first
lightcurve peak". I guess you are talking about I-band here although
the previous sentence is all about B-band. Please clarify.
You quote dispersion ~0.4 for the uncorrected B-band hubble
diagram. This sounds rather large compared to what I remember us
quoting in various proposals (0.3?). Where does this come from?
"The found dispersion (0.19 mag) is larger..." I'm not sure what
dispersion you are talking about now. Stretch-corrected B-band?
Section4:
The supernova images were aligned and scaled... say whether you mean
in flux or spatial scale.
In the tables in section 4 you give J magnitudes and I magnitudes. You
should label the I-mags as k-corrected to the rest-frame.
Section 4.4: I'm not quite sure I understand what you've done in order
to make a set of templates which you then use for a one-parameter fit
to the z~0.5 SNe. How did you collapse the 42 lower z ones down to one
parameter? Are you using the curves in Figs 7 and 8?
Section 5:
You quote confidence levels with & without systematic
uncertainties being accounted for, but you dont say what these
uncertainties are. Are these the same as mentioned in section 6.1?
In the conclusions you mention that a non-dust model is preferred at
90% confidence but I could not see this result mentioned in section 5,
where I would expect it to come from.
Section 6:
To be honest I found this section a bit frustrating - there is a lot
of quite detailed analysis to understand, and at the end of it all
we're told there were no significant conclusions. If possible I would
try to shorten this section.
Section 8: you mention the Ca triplet again, and again I dont see why
it should be a problem. Also you mention selection effects for bright
objects during the search campaign - this will get people worried so
you should be more specific.
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Typos etc:
Intro :
Replace "The I-band lightcurves typically show..." with "I-band
lightcurves of SNeIa typically show..."
Shorten the sentemce "..offers a way to investigate the possibility of
finding means for..." to "... offers the possibility of.."
up-to-date should be "to date" in both cases where you use it.
Remove "the" and add "for" in "Furthermore, (the) additional colour
information is used to test FOR extinction ..."
Section 2:
"includes also" should be "also includes"
"spectroscopically normals" should be "spectroscopic normals"
"coincide generally with the one expected" should be "coincide
generally with those expected"
"not giving evidence for biases" should be "thus no evidence was found
for significant biases"
Figure 1: What are the lightcurves normalised to? (looks like first
peak is normalised to 1.0). The residuals are also normalised to the
same thing I guess?
"more feeble" should be "weaker"
Fig 8: two of the SN names lie on top of each other - can you displace
these so they can be read?
section 3: alpha_I=1.13pm0.19 should be 1.13 +/- 0.19
Fig 10 caption: "Effective magnitude I maximum" should be "effective
I-band maximum" or something. Spell out CT.
Fig 11 caption: say that the spectral template is plotted on an
arbitary flux scale (not amplified by a factor 4, since you dont give
actual flux units anyway).
Section 5:
"We want to" should be "the goal of this work is to.."
"..were thus corrected for Milky Way extinction in the observed band
only." What other band would you correct it in? I think you mean this
was the only correction applied, in which case you should say "the
only correction applied was for Milky Way extinction"
"..assumed as such to accound for" should ve "assumed sufficient to
account for"
Fig 15 caption: The middle sentence needs a verb!
Section 6: "..and a comoving density.." missing word? should it be
"constant comoving density"?
"the authors neglected" should be "Riess et al. neglected"
(people often use "the authors" to mean themselves in a paper).
.." dash-dotted line the 99.7% probability" - probablility of what?
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