From: Chris Lidman (clidman@eso.org)
Date: Thu Mar 30 2006 - 11:10:28 PST
Hi Gabriele,
One other thing. I've gone through and reclassified all SCP SNe from
1992 onwards. There
is nothing dramatically new here, but it gave me an opportunity to see
all the spectra.
The SCP has some wonderful spectra from as early as 1994. It is
disappointing that we
have not manage to publish them yet.
Regards,
Chris.
On Mar 30, 2006, at 8:54 AM, Gabriele Garavini wrote:
> Hi Chris,
>
> I have been working on a new version of the evolution paper (in
> attachment).
> The main changes are related with figs 8, 9, 10.
> Briefly, there was some concern on the MgII ew values pre-max for the
> high-z, these are now solved. They were actually due to the low-z
> sample.
> It turned out that in the pre maximum bins the low-z sample is pretty
> poor. The average trend is biased toward the values of 94D that seems
> to be in some sense an outlayer.
> I've added some warnings in the text (section 3.5) about this issue
> and redone the plot 8, 9, 10 showing the 95% probability instead of
> the 68%, which seems more appropriate because of the possible error in
> the estimated central value.
>
> I would like to resubmit the paper next week if you agree. The journal
> contacted me asking what was our plan for this work.
>
>
> All the best
> Hasta la vista!
> Ciao
> Gabriele
>
>
>
> <Evolution_v3.3.pdf>
>
>
>
> On Feb 19, 2006, at 11:39 PM, Chris Lidman wrote:
>
>> Hi Gabriele,
>> Thanks for the revised version. Most of my suggestions now consist
>> of
>> minor tweaks to help improve the clarity of the paper.
>>
>> I am sure that I have missed some things, especially since I've
>> just returned from a long shift on Paranal and I am rather
>> tired. After you have read my comments, I suggest that you give the
>> paper to someone in the collaboration who can carefully read the
>> paper.
>>
>> I do not think that you should add new SNe to this paper. On this
>> point,
>> we agree. Once this paper is done, what are your plans? Are you
>> thinking
>> on working on the SNLS data set? This was the thrust of my question
>> in my earlier e-mail.
>>
>> Regards,
>>
>> Chris.
>>
>> Abstract
>> ========
>>
>> You make the following comment on the revised abstract,
>>
>> "In this way we are not mentioning at all the results of the EW for
>> the
>> low z. I know is not the main point of the paper but I wonder if it
>> wouldn't be good to put it in the abstract for making the article
>> more appealing."
>>
>> Yes, you are right. Here is another version, which could
>> probably still use some tweaking."
>>
>> "We develop a method to measure the strength of the strongest
>> absorption features in Type SNe Ia spectra and use it to make a
>> quantitative comparison between the spectra of Type Ia supernova at
>> low and high redshifts. Through the strength of these features and
>> through measurements of the Ca II H and K velocity we show that the
>> spectra of a high redshift sample, consisting of 12 SNe Ia with
>> redshifts ranging from 0.212 to 0.912, are quantitatively similar to
>> the spectra of a low redshift sample. One supernova in our
>> high redshift sample, SN 2002fd at z=0.279, is found to have spectral
>> characteristics that are associated with peculiar 91T/99aa-like
>> supernovae."
>>
>> A general comment
>> =================
>>
>> In many places of the paper you use the acronym EW. This is OK, but it
>> can lead to clumsy word constructions in some cases. I take the the
>> first line in the caption of Fig. 4 as an example. Which do you think
>> is better,
>>
>> "Measured EW values corresponding to ..."
>>
>> or
>>
>> "Equivalent width of the Fe II 4800 feature as a function of phase."
>>
>> Sometimes, it is better to spell out the acronym. This was one
>> example.
>> There are others.
>>
>> Section 1
>> =========
>>
>> 4th paragraph
>>
>> The Balland et al. paper (A&A, 445, 397) is now out. We should add
>> this article
>> to the list of references in the last sentence.
>>
>> Section 2.1
>> ===========
>>
>> 2nd paragraph
>>
>> "... over luminous object" -> "... over-luminous objects"
>>
>> Rephrase the sentence that starts with "Therefore, we consider ..." to
>>
>> "The additional scatter that would be introduced by using data with
>> lower
>> signal-to-noise ratios would obfuscate the result"
>>
>> or something similar.
>>
>> 3rd paragraph
>>
>> "... error spectrum. It was ..." -> "... error spectrum, which was
>> ..."
>>
>> 4th paragraph
>>
>> "The estimated galaxy contamination, ..." -> "The contribution of the
>> galaxy
>> light, ..."
>>
>> Figure 1 is a good start. One of the things we need to be aware of, is
>> that non-experts may think that the SNe spectra in this figure are
>> poor when the opposite is true. It is important that we do not create
>> a negative impression with this figure. Here are some suggestions to
>> make it better.
>>
>> - For SNe with z > 0.4, put the label on the right. This will reduce
>> the
>> amount white space that is in the figure.
>>
>> - Make the SN labels larger
>>
>> - Remove the word epoch, put the epoch in brackets and add a note in
>> the
>> text explaining what the number in brackets means.
>>
>> - Mark the regions that are used in the EW analysis. See Balland
>> et al. for an example.
>>
>> - Try smoothing the data with a Savitsky-Golay filter. See Balland et
>> al.
>>
>>
>> Section 2.3
>> ===========
>>
>> 1st paragraph
>>
>> Maybe it is worth explaining what 91Taa means when it is first
>> used. E.g. you could say, "(We follow the convention of Li et al. when
>> describing 91T/99aa-like SNe by using 99Taa to represent this SN
>> subtype.)."
>>
>> Rephrase
>>
>> "The Ca II H&K feature ... SN 1991T like SNe."
>>
>> to read
>>
>> "The Ca II H&K feature in SN 2002fd is more prominent than the Ca II
>> H&K feature in SN 1991T, but less prominent than the Ca II
>> H&K feature in normal SNe Ia, such as SN 1994D."
>>
>> or
>>
>> "The strength of the Ca II H&K feature in SN 2002fd is between
>> that of 91Taa-like and normal SNe."
>>
>> Table 1.
>>
>> The font for footnotes "a" through "d" in the table is different to
>> the font used below the table. Same comment applies to Table 2.
>>
>> Replace
>>
>> "that could affect the cosmological measurements".
>>
>> with
>>
>> ", which might affect the derivation of cosmological parameters
>> from SNe Ia."
>>
>> Section 3
>> =========
>>
>> 1st paragraph
>>
>> "phase" -> "phase,"
>>
>> "distribution properties" -> "distributions,"
>>
>> "see for a review Filippenko (1997)" -> "see Filippenko (1997) for a
>> review"
>>
>> "case" -> "cases"
>>
>> "severe" -> "dramatic"
>>
>> "and Type Ia subtypes have been identified to account for a
>> morphological classification"
>>
>> ->
>>
>> "resulting in the definition of SNe Ia sub-types."
>>
>> "dishomogeneities" -> "dissimilarities"
>>
>> "my means" -> "by means"
>>
>> 2nd paragraph
>>
>> "compare" -> "comparing"
>>
>> "In the following section EW is defined and the properties are ...
>> discussed"
>>
>> ->
>>
>> "In the following sections, we describe how we measure the EW of the
>> broad absorption features in SN Ia spectra and we apply it to a sample
>> of nearby SNe Ia."
>>
>> I suggest that you delete the last three sentences in this paragraph,
>> unless
>> you are sure that Gaston will publish his paper.
>>
>> Section 3.1
>> ===========
>>
>> The first and second paragraph needs some rewording.
>>
>> 2nd paragraph
>>
>> "i.e." -> "because of"
>>
>> 3rd paragraph
>>
>> "As already mentioned" -> "As already mentioned,"
>>
>> In the footnote 3 on the bottom of page 6.
>>
>> "and the possible" -> "with the possible"
>>
>> In the last paragraph you can say "By definition, the rest frame EW
>> ..."
>> and you can then delete the parenthetical remark.
>>
>> Section 3.2
>> ===========
>>
>> In the spirit of the titles you have used for sections 3.1 and 3.2, I
>> would
>> suggest the abbreviated title - "Measurement technique"
>>
>> 1st paragraph
>>
>> "Measuring EW ..." -> "Measuring the EW ..."
>>
>> "since the identification of the local maxima bounding ... visually."
>>
>> ->
>>
>> "since the local maxima bounding an absorption feature can be
>> identified
>> easily."
>>
>>
>> "poor quality spectra" -> "low signal-to-noise data" I prefer this
>> because the
>> high redshift data are not poor quality data.
>>
>> "complex" -> "difficult"
>>
>> Delete the word practical
>>
>> "which minimize" -> "that minimizes"
>>
>> In the list of items on page 7.
>>
>> "on Eqn. 1" -> "in Eqn. 1"
>>
>> "To the data, ..." -> "A straight line is fitted to the data in the
>> fitting
>> regions"
>>
>> 2nd paragraph
>>
>> "Larger wavelength span would ..." -> "Larger wavelength spans would
>> ..."
>>
>> Section 3.3
>> ===========
>>
>> Last paragraph
>>
>> "presents photometric" -> "has photometric"
>>
>> "which make" -> "that make"
>>
>> Section 3.4
>> ===========
>>
>> Last paragraph
>>
>> "The decrease of EW ..." -> "The decrease in the EW ..."
>>
>> Delete "by giving the relative decrease ... types."
>>
>> You can then adjust the title of Table 6 to read
>>
>> "The fractional decrease in the EW corresponding to a 10% increase in
>> the
>> amount of contamination from the host."
>>
>> Replace
>>
>> "Since the SNe ... on that end"
>>
>> with
>>
>> "Since SNe Ia near maximum light are generally bluer than their hosts,
>> errors in estimating the amount of host galaxy contamination
>> leads the larger EW errors for features at redder wavelengths."
>>
>>
>> Section 3.5
>> ===========
>>
>> 1st paragraph
>>
>> The first sentence is not necessary. The second is sufficient.
>>
>> Section 3.5.1
>> =============
>>
>> 1st paragraph
>>
>> "The values of the EW increase constantly ..." -> "The EW increases
>> ..."
>>
>> 3rd paragraph.
>>
>> The paragraphs starts with "This", which might confuse the
>> reader. Perhaps, the new paragraph should start with the 2nd last
>> sentence of the 2nd paragraph, i.e. the one that starts with "The
>> different sub-types ..."
>>
>> \delta is used in the text, \Sigma in the table. Actually, in this
>> case
>> \delta is more appropriate for columns 6 and 8. I'm sorry if I have
>> changed my mind on this point.
>>
>> \delta is in the footnote. The footnote appears on the page before
>> the table.
>>
>> Section 3.5.2
>> =============
>>
>> 3rd paragraph.
>>
>> "Other SN subtype ..." -> "Other SN subtypes ..."
>>
>> Section 4
>> =========
>>
>> in point 2
>>
>> "equivalent width measurements" -> "the equivalent widths"
>>
>> Section 4.1.1
>> =============
>>
>> 1st paragraph
>>
>> "would tend to" -> "might"
>>
>> 3rd paragraph
>>
>> "data quality range found in our data set" -> "signal-to-noise ratios
>> in the
>> data,"
>>
>> "estime" -> "estimate"
>>
>> The biggest weakness of the technique we use to estimate the amount of
>> host galaxy subtraction is that we use a fixed number of galaxy
>> templates.
>> In real data, host galaxy SEDs will be more varied, so the estimate in
>> how accurate we can remove the flux of the host galaxy is probably
>> an underestimate.
>>
>> Section 4.1.2
>> =============
>>
>> 1st paragraph.
>>
>> "Figs. 9 and 8" -> "Figs. 8 and 9"
>>
>> EW's indicates possession, which is not the case here. Use EWS.
>> Personally,
>> I find the acronym EWS rather ugly. It might look nicer if you spell
>> out the acronym. Also "measured EW values" is better written
>> "equivalent
>> widths".
>>
>> The semi-colon after "parenthesis" should be a full stop.
>>
>> "possible fitting regions uncertainties" -> "possible fitting region
>> uncertainties"
>>
>> 5th paragraph
>>
>> "Fig. 10 show" -> "Fig. 10 shows" and a full stop at the end of the
>> sentence.
>>
>> "low-redshift normal and under-luminous" -> normal and under-luminous
>> low-reshift"
>>
>> Last paragraph.
>>
>> "lower metallicity progenitor" -> "lower metallicity progenitors"
>>
>> The other possibility, of course, is that the Lentz models are wrong.
>>
>> Table 10.
>>
>> The first sentence is messy. Try
>>
>> A statistical comparison of the equivalent widths of high-redshift SNe
>> with the equivalent widths of normal and under-luminous low-redshift
>> SNe.
>>
>> If it is possible, replace the word "faint" with the word
>> "under-luminous",
>> so that it is clear that the faint and under-luminous SNe are the
>> same.
>>
>> Section 5
>> =========
>>
>> 1st paragraph
>>
>> "We also find based on spectral properties alone that, .." -> "We also
>> find, based on spectral properties alone, that ..."
>>
>> 3rd paragraph
>>
>> "EWof" -> "EW of" (occurs twice)
>>
>> Last paragraph.
>>
>>
>> "difference in" -> "differences between"
>> "has" -> "has been" in the last sentence
>>
>> I feel that something is lacking in this paragraph.
>>
>> European Southern Observatory
>> Alonso de Cordova 3107, Vitacura
>> Casilla 19001, Santiago 19
>> CHILE
>>
>> Ph. 56 2 463 3106
>> FAX 56 2 463 3001
>>
>>
> ========================================================
> Department of Physics, Stockholm University
> AlbaNova University Center, SE-106 91 Stockholm, SWEDEN
> Fax: +46 8 55378601 Phone: +46 8 55378769 ,
> e-mail: gabri@physto.se
> ICQ: 148161845, AIM: gabrigaravini, msn: garavini@in2p3.fr
> skype: gabrielegaravini
>
>
>
European Southern Observatory
Alonso de Cordova 3107, Vitacura
Casilla 19001, Santiago 19
CHILE
Ph. 56 2 463 3106
FAX 56 2 463 3001
This archive was generated by hypermail 2.1.4 : Thu Mar 30 2006 - 11:10:52 PST