From: Robert A. Knop Jr. (robert.a.knop@vanderbilt.edu)
Date: Thu Mar 20 2003 - 13:05:37 PST
Looking at the gersontable from the last paper, it looks like we assumed
a U-B color effectively closer to -0.5 than -0.3 *for purposes of
calculating E(B-V)*. In particular, to reproduce the sn9784 E(B-V), I
have to assume that
(B-V) - (U-B) = +0.366
which, for a (B-V) of -0.11 for a s=1 supernova (given at the bottom of
the gersontable in the notes), is a U-B value of -0.47.
All colors that I quote here are at the day of Bmax. (NOTE ALERT: that
-0.11 from the previous paragraph was Bmax-Vmax, not B-V at Vmax, so
I'll be slightly wrong as as a result... although that -0.11 looks
*awfully* blue to me to be Bmax-Vmax, as it's already 0.04 or 0.05 bluer
than what I think is a resonable B-V at Bmax for s=1. You expect
Bmax-Vmax to be *redder* than B-V at Bmax!)
The K-corrections, however, if you poke at them, seem to give U-B of
about -0.3, and B-V of about +0.02. In other words, yes, it appears
that our K-corrections and our "assumed colors" were not internally
consistent, or so it would seem to me.
At some point, I'm going to object to use of P99 as a reasonable
standard of comparison *at all* for colors and K-corrections....
-Rob
-- --Prof. Robert Knop Department of Physics & Astronomy, Vanderbilt University robert.a.knop@vanderbilt.edu
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