From: Lifan Wang (lifan@panisse.lbl.gov)
Date: Sat Mar 15 2003 - 13:03:04 PST
> From owner-deepnews@listserv.lbl.gov Sat Mar 15 12:42:04 2003
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> To: Greg Aldering <aldering@panisse.lbl.gov>
> Cc: deepnews@lbl.gov
> Subject: Re: late-time fitting debate
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> On Sat, Mar 15, 2003 at 12:37:38PM -0800, Greg Aldering wrote:
> > 2) Since P99, in particular in AKN00, we generally agreed that stretch
> > begins to fail and our knowledge of SN lightcurve variety is poor
> > starting 25-40 days after max. This argues for the concept of an
> > uncertainty on the TEMPLATE (as Saul has suggested).
>
> This isn't going to happen in this paper... clearly!
>
> The best way to simulate it is to stick uncertainties on the later
> points, perhaps correlated.
>
> > Putting this altogether, I suggest that we cut points after 60
> > rest-frame days (but not final refs of course) as in P99, and add in an
> > error floor, with the error floor to be interpreted as accounting BOTH
> > for uncertainty in the template shape and stretchability at late epochs
> > and for some uncertainty in the final-reference subtraction for nearby
> > SNe. We can cite this a combining the treatments presented in P99 and G01.
>
> I like this approach and am happy with it, if everybody else accepts
> it. (I'll use an 0.007 error floor unless I hear otherwise.)
>
> To avoid cutting final refs, I probably will just cut everything after
> 60(1+z) days but before 200 days after B-max.
>
I do not like this approach, but as Rob said any details would not
affect the cosmology very much so I am not againest doing it this way
just for the sake of not slowing down this paper.
Please allow me to remark that the errors bars from Hamuy are
statistical+0.03 mag. The 0.03 mag was added to account for the
uncertainties due to calibration and subtraction. This is why
Hamuy's errors are all about the same from max to late time.
From CMAGIC fit, we know this is an "over"estimate of the errors.
Late time does not stretch simply because the half life time of 56Co
does not stretch. So my preferred approach is to do stretch fit only
for data before nebular phase.
> -Rob
>
> --
> --Prof. Robert Knop
> Department of Physics & Astronomy, Vanderbilt University
> robert.a.knop@vanderbilt.edu
>
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