From: Vitaliy Fadeyev (VAFadeyev@lbl.gov)
Date: Mon Feb 02 2004 - 10:40:43 PST
Dear Serena,
> thank you very much for your work. I think we are getting closer to the
> final numbers for 1999Q. What I find annoying however, is the fact that we
> don't get the same tmax as Tonry, given we are using the same data set.
It may be annoying, however, I should point out that using the same data
is not a guarantee for the same results. As far as I know, different methods
were used in:
a) photometry,
b) K-corrections,
c) lightcurve fitting.
Given that the analysis machineries are different in all these areas,
I would not actually expect the results to be exactly the same.
> From this point of view, Ariel and I have noticed that there are data
> points in the lightcurve you are fitting which are above day 40 (or even
> 50). Those points are certainly worsening your chisq, since they are
> always deviant. As the standard SCP procedure however, is not to include
> points later than 40 days after max in the fit (I believe this was the
> case also for Knop et al.), I think you should try to compute the chisq
> value for all the cases excluding the latest 1 or 2 points.
> Looking at the residuals in your plots, I expect this to give about the
> same chisq in all the cases (except case 1 perhaps). If this is true, and
> we get the same result as Tonry, than we can more easily explain in the
> paper what we did. Thank you again for your help.
According to the Rob's paper, 40-50 days threshold refered to the rest frame,
and the restframe coverage of sn1999q does not extent beyond 40 days.
(The snminuit lightcurves have observation time axis.) Because of this,
I'm not sure if I want to redo the fits.
Also, deviations for the late-time photometry points are not always large.
They only become substantial when the max-time is fixed to Tonry's value.
Cheers,
vitaliy
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