From: Robert A. Knop Jr. (robert.a.knop@vanderbilt.edu)
Date: Tue Mar 11 2003 - 11:39:28 PST
Does anybody know how to parse the Delta, AV, and mu_0 parameters into a
mB and stretch? I'm talking about the parameters listed in Riess 1998
Table 7 (the high-z team's result paper from that year).
For most of the supernovae, I'm just using their delta-m-15 data instead
of the MLCS stuff, since that's easily converted. Thus far, I haven't
messed with any of their "snapshot" supernovae, and I don't expect them
to make a whole heck of a lot of difference. However, if I do want to
get them in there, I need to figure out what to do with these
parameters. mu_0 is a distance modulus, but it's not obvious how to
turn that into m_B (since one not only has to know the assumed M_B, but
also how all the other parameters affect it). Delta is some MLCS
related thing.
I haven't taken the time to parse and understand MLCS, nor will I. If
somebody can offer me a simple cookbook to turn those parameters into
mB, AV (or, better, E(B-V)), and dm15 (or, better, s), I will use them.
Otherwise, I will just ignore the snapshot supernovae from their paper.
(By the way, the degree to which they are lying when they claim to have
corrected for host galaxy extinction is pretty huge. The prior really
goes a long way to eliminating your most significant error bar. And, so
far as I can tell, for their z=0.97 supernova, they assumed a delta
function for the PDF on E(B-V)-- rather than what would seem more
natural, just the prior. In other words, it looks like they put that in
as if it's E(B-V) value were 0+-0.)
-Rob
-- --Prof. Robert Knop Department of Physics & Astronomy, Vanderbilt University robert.a.knop@vanderbilt.edu
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