Re: The 1999ac paper.

From: Gabriele Garavini (gabri@physto.se)
Date: Tue Dec 23 2003 - 10:37:12 PST

  • Next message: Gabriele Garavini: "Re: SN 1999ac comments."

    Dear Rollin

    thank you very much for your comments, I look forward to have your
    detailed version. I'm also waiting for the others to send me comments,
    so
    far you have been the only one.

    > Clearly the most important result of this analysis is the pretty good
    > identification of C II and perhaps the C III at early times. That's a
    > very good use of Synow. The focus on the C identification is there in
    > the paper, but I think its framing in Section 1 needs a bit of work.
    > Finding C in a SN Ia is about as important as it gets for models, so a
    > more clear discussion of the background would help. For example, I
    > notice that you've got the appropriate references for W7, but for the
    > parallel discussion on DD models you haven't got any, and you leave
    > out some important models. Perhaps it would help your understanding
    > to if you went back and took another look at what papers were
    > appropriate to put here?

    I think you are right, the original idea was to make this paper shorter
    than the one on 99aa, and consider this as a 'follow-up' paper, if you
    see
    what I mean. However, being short does not mean being not complete or
    not exhaustive. I hope you can give me some references for the models
    you
    think are meaningful to introduce and/or cite.

    > I am concerned about your classification of 1999ac as 1999aa-like (I
    > take you to mean in the Li et al sense). First you make this claim
    > and then I look at Figure 3 and I'm not convinced. Without plotting
    > them myself, I tend to think that the blue of 1999ac looks a lot like
    > 1990N, and then in the red, somewhere in between. Maybe this is what
    > you
    > mean by 1999aa-like, but then again I am confused. I guess my point
    > here is that you should take a long hard, honest look at that figure
    > and see if you know what I am talking about. I'm happy to find out
    > if you think I am wrong, I just want to know more about why you think
    > this way.
    > What I'd like also is if (somewhere) you could define precisely what
    > you
    > mean by peculiar, if for no other reason than to educate readers not
    > really familiar with the Li/Branch debate over the peculiarity rate.
    > You do reference papers, but the definition needs to be included for
    > the purposes of depth.

    I think you pointed out one of the main issues with peculiar object
    these
    days. This is the problem with the classification of peculiar objects
    itself. I will follow your suggestion and have a close look at the
    spectra. My 'classification' was 99aa-like even more close to normals. I
    think we are speaking about the same think but wording it differently.
    If
    you see 99aa as in the middle between 91T and normals and 90n as an
    extreme of normals on the side of 91t -- as I think I read somewhere
    (maybe Hatano) -- I think we agree. A good peace of work that I'm
    thinking
    to do in future is trying to find an observable to quantify this
    statements. As we go on in finding odd balls classify them as peculiar
    of
    some type looks more and more tricky. I guess SN-factory will help a
    lot.

    > Also, I think it's perfectly acceptible to include fits to the entire
    > spectral range of the supernova for just one ion, or for all the other
    > utilized ions minus one to prove a point. Close-ups are good in some
    > cases, but often I want to see how things look spectrum-wide. I am
    > pretty sure David's got examples of this throughout his catalogue of
    > fits.

    I guess you are thinking especially about CII and CIII. That's probably
    a
    good point. I'll try to see if it can make it more
    evident.

    > Oh, and I've got some 1998aq spectra you might want to look at. I got
    > them through David, and they are supposed to be going up on Suspect
    > soon (in which case it would be legitimage for you to use them; they
    > are public then). You could do your minimum fitting routine on it
    > and include those data in your velocity plots. (Incidentally, how
    > automated is the code you use to do this? This is the Levenberg-
    > Marquardt code you used in the previous paper? Do you need something
    > so complicated for this? Too interesting: I digress...)

    New and interesting data are always good. If you think there is no a
    problem I'd like to have them. Actually the program I use to fit
    velocities is a 'clicking' tool I wrote in IDL. You do not really need
    something so complicated but the Levenberg-Marquardt method was already
    implemented in IDL and that's why I used it .

    Thanks a lot
    Merry Xmas

       Gabriele

    --
    ________________________________________________________________________
    _____
    Gabriele Garavini (gabri@physto.se)
    FYSIKUM-Stockholm University Roslagstullsbacken 21 S-106 91 Stockholm
    SWEDEN
    Phone:+46 8 55378661 Fax:+46 8 553 78 601



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