From: Alex Conley (aconley@panisse.lbl.gov)
Date: Wed May 07 2003 - 20:08:31 PDT
I can tell you from experience that sn1995bd is a 'funny' supernova
when it comes to lightcurve fitting. If you look at my SN by SN
comments when I refit all of the SNe as a stability test, this is
what I had to say about 95bd:
sn1995bd -- a piece of junk. The fits move around a bit when the initial
conditions change, but mostly this just misses the peak badly, en
when a floating offset is used. I'm glad this one gets excluded from the
fits.
and 1996bo
sn1996bo -- solid, both fixed and floating. However, the floating fit is
worse. It seems to miss the peak. Again, using floating offsets has
ruined a perfectly good fit
Here I felt that floating offsets were a mistake.
As for the other Riess SNe:
sn1994M -- solid
sn1994S -- pretty solid, but the V peak seems slightly off. Changing to
floating offsets doesn't really improve this. In any case, changing
the initial conditions changes the error bars a bit, but not the central
values.
sn1995ac -- solid
sn1996bl -- solid
The full reference for these fits is
http://panisse.lbl.gov/collab/archive/hstpaper/0098.html
and a bit more description of what I was doing
http://panisse.lbl.gov/collab/archive/hstpaper/0093.html
Attached to the first email is a tgz containing all of the output
postscript for the fits.
Alex
On Wed, 7 May 2003, Greg Aldering wrote:
> HERE IS THE REVISED VERSION:
>
> Hi Rob,
>
> I started to investigate "what'sup" with SN1995bd and SN1996bo and
> found that your B-band magnitudes differ, sometimes by a lot, from the
> published Bmax tables from Table 3 of Riess 1999 (the 22 SNe paper).
> Further investigation showed generally poor agreement. Can you
> comment?
>
> no extinction cor
> Bmax mB mBcor Bmx-mB
> R99 SCP03 SCP03
> ---------------------------------------------------------------------------
> SN1995bd 17.27 15.32 17.39 HUGE! (weird that mB_cor is much better)
> SN1996bo 16.15 15.85 15.92 +0.30
>
> also, here are the other Riess 1999 SNe for comparison
>
> SN1994M 16.35 16.25 16.13 +0.10
> SN1994S 14.79 14.78 14.93 +0.01
> SN1995ac 17.19 17.05 17.37 +0.14
> SN1996bl 17.08 16.67 17.14 +0.41 way off!
>
> These seem like large differences (some extremely large) given the
> small uncertainty you quote from fitting the same data (few tenths of a
> magnitude). Some of this is probably due to the crudeness of the
> delta-m15 fits quoted in Riess 1999. I seem to recall that in P99 we
> may have had a similar issue with the H96 data, but I haven't checked
> that yet.
>
> These offsets aren't enough to explain the anomalous extinction for
> 95bd and 96bo, unless the extinction estimate is off. So, I looked at
> your E(B-V) values and compared them to the value in Phillips 1999
>
> your ph99 tail ph99 peak
> E(B-V) E(B-V) E(B-V)
> ------------------------------------------------------
> SN1995bd 0.339 0.242 NOT GIVEN - dm15 < 0.9
> SN1996bo 0.390 0.358 0.385
>
>
> So here, the agreement for E(B-V) at max for 96bo is good. 95bd may be
> another question, but it isn't as big an outlier as 96bo in the
> extinction-corrected fits.
>
> On to more data sifting.
>
> - Greg
>
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