From: Robert A. Knop Jr. (robert.a.knop@vanderbilt.edu)
Date: Wed Feb 19 2003 - 16:05:44 PST
On Wed, Feb 19, 2003 at 03:43:12PM -0800, Lifan Wang wrote:
> Rob,
>
> I totally agree that it is impossible to make this perfect. But
> you did not answer my question of if the fixed slope fit of the 92ag has
> converged. So I am attaching my arguement below that it did not converge.
That fit hadn't converged-- I've got another one which, starting at
different points, did better, but is still clearly bad; chisquare is
384, and there are obvious systematic problems. (This is probably what
I was looking at before when I decided to go with the floating-zero fit
here.) The problem still exists; it's not as egregious as I had said,
but it's still pretty egregious.
Note that the uncertainties on some of those lower points, on the scale
we're using here, are something like 0.003. No, I don't really believe
that, but if you trust the magnitude uncertainties in Hamuy's paper,
that's what you get. Since there is a slope to them, this is why an
offset of even 0.03 in the baseline (where 1 is the height of the
maximum point) can drive a big change in the rest of the lightcurve.
-Rob
-- --Prof. Robert Knop Department of Physics & Astronomy, Vanderbilt University robert.a.knop@vanderbilt.edu
This archive was generated by hypermail 2.1.4 : Wed Feb 19 2003 - 16:06:05 PST