[Fwd: Re: Gaston's paper] (fwd)

From: Gaston Folatelli (gaston@physto.se)
Date: Thu Dec 18 2003 - 01:59:47 PST

  • Next message: Saul Perlmutter: "Comments on Equivalent Widths paper."

    These are Peter's comments on the sixth version of the paper, sent on Dec
    3rd.

       - Gaston

    ---------- Forwarded message ----------
    Date: 03 Dec 2003 20:39:19 -0300
    From: Chris Lidman <clidman@eso.org>
    To: Gaston Folatelli <gaston@physto.se>
    Cc: eqwidths@panisse.lbl.gov
    Subject: [Fwd: Re: Gaston's paper]

    Hi Gaston,
      Please find enclosed a list of suggestions from Peter. In addition to
    the corrections listed here, Peter will also FAX you a list of
    grammatical corrections.

    Cheers, Chris.


    attached mail follows:



    Hi all,

    Here are my comments on the paper.

    (1) Redo the abstract.

    (a) It is not well written.
    (b) The statement about the amount of follow-up time being less is false -
    well perhaps misleading is a better word - extinction measurements were
    not accounted for and one would have to factor in this plus the amount of
    time necessary to id the SN in comparison to taking this higher-quality
    spectrum without host galaxy contamination (which definitely effects the
    measurement of alpha(2+3).
    (c) The statement about the ability to measure these features at high-z
    should be studied a little more. I will mention this below.

    This is a good paper and it should start with a good abstract. Other than
    the first sentence this abstract fails to deliver. More often than not
    this is the most important part of a paper. Effort should be put into
    this since there is no way (regardless of how good the rest of the paper
    is) that this could go before the entire group before this is cleaned up.
    People would not bother with the rest...

    (2) References look fairly good. I can add a couple in the next version.

    (3) English problems abound. I gave up after the first two pages marking
    them up. I can fax them to someone if you would like, but I won't type
    them in, there are too many.

    (4) Remove the Ni II Fisher et al comment. It is speculative at best. You
    should just state that Ca II might be less abundant and/or the higher
    temperatures reduce the strength of these features.

    Things to do science-wise:

    (1) The Saha distance to SN 1991T is a problem since all the other ones
    are based on a Freedman et al measurement. I would suggest using the
    Gibson et al measurement (cited below) since it will be consistent with
    Freedman et al. Basically it doesn't matter which one you use as long as
    you are consistent.

    (2) Table 7: Add the distance moduli in the table for each SN as well as
    the measurement for extinction with uncertainties (and references for
    each). Also I completely dislike the use of M_B(max) and M_B(max)(dm15).
    This also applies to the bottom of figure 12.

    There is a measured peak brightness for an extinction-corrected SN Ia.
    This is M_B(max). This is fine. The only use for M_B(max)(dm15) is for
    the residual plot. Why not just show residuals (M_B(max) - the equation
    for determining the brightness of a Ia w/ dm15) This is MUCH less
    confusing.

    I say this also since when you use the consistent analysis of SN 1991T
    the point in Figure 12 for 1991T will move down by ~0.3mag or so. Then the
    correlation in the bottom figure will go away. Which is neither good nor
    bad, just interesting. The modified figure should be kept, regardless.

    (3) Do a simple test for the effect of host galaxy contamination on the
    measurement of alpha(2+3). Just add an early and late type galaxy spectrum
    (normalized to V-band) in amounts going from 0 - 100% of the light in a
    given SN spectrum (pick your favorite) and redo the calculation. Then you
    can fairly state how well you can make this measurement at high-z under
    these conditions and note the systematics involved. A graph of alpha(2+3)
    vs. host gal. contam. would be enlightening.

    Cheers,

    Peter

    @ARTICLE{2001ApJ...547L.103G,
        author = {{Gibson}, B.~K. and {Stetson}, P.~B.},
        title = "{Supernova 1991T and the Value of the Hubble Constant}",
        journal = {\apjl},
        year = 2001,
        month = feb,
        volume = 547,
        pages = {L103-L106},
        adsurl =
    {http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2001ApJ...547L.103G&db_key=AST},
        adsnote = {Provided by the NASA Astrophysics Data System}
    }

    __
    Peter E. Nugent
    Staff Computational Scientist - Scientific Computing Group - NERSC
    Lawrence Berkeley National Laboratory
    M.S. 50F-1650 - 1 Cyclotron Road - Berkeley, CA, 94720-8139
    Phone:(510) 486-6942 - Fax:(510) 486-5812
    E-mail: penugent@LBL.gov - Web: http://supernova.LBL.gov/~nugent



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