From: Gaston Folatelli (gaston@physto.se)
Date: Mon Jul 21 2003 - 05:46:00 PDT
Hi Chris,
I also think the best is using absolute magnitudes (because that's what
we use in the end). The caveat is though
that these are harder to obtain and less accurate than the Delta_m15. The
M_B values I use were taken from the literature and are based on
various different methods. There seems to be systematic differences
between distance determination methods, as I stated in the latest
document.
With respect to that, I modified a bit the document. In the caption to
Figure 1, I added the methods used to determine distances to the public SNe.
I also corrected the text in the last paragraph, which was erroneous.
You'll find the new version in the same place as before:
http://www.physto.se/~snova/internal/papers/eq_width/eq_width.html
(usual SCP access)
I'll work on making the feature definitions clearer and on the possible
correlations you suggest. It looks to me that linear regressions
won't work when absolute magnitudes are involved. The tail due to
the under-luminous SNe deviates from possible linear relations.
Finally, there's a great potential in the color analysis
related to Figure 9, but I still need to collect the photometry data to
complete it.
I'm not restricting the analysis to B-I only. All colors are being
considered to see what's more convenient to use in the end.
Cheers,
-Gaston
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