From: Saul Perlmutter (saul@lbl.gov)
Date: Tue Nov 12 2002 - 08:30:24 PST
Yes, we had looked into various alternative identifications of the lines, but
in the end the evidence was very strong that the galaxy is at z = 1.48.
There is a good match to the Magnesium line also, and the elliptical or Sa
galaxy fits to that redshift even when you ignore the narrow lines. Note that
we have never seen [OIII] 5007 by itself and that a number of other lines
should also be seen if [OIII] is present, but none of them are there. At
z=1.48, the galaxy + SN, with the appropriate ratio (when compared to the
percent increase) is a consistent fit with the data. (Have a look at the fit
that Lifan should be putting in Berkeley right now -- Andy: can you get this
onto the web so everybody can see it?) So, it's not that the additional
identification of the extra light beyond the galaxy light as due to an SN Ia
is conclusive, but just that it seems to be the best bet. It would still be
very interesting to see if there are other SNe that have the same feature that
SN Ia have that makes the fit better.
Gaston Folatelli wrote:
> We have tried the infrared technique for sky subtraction on SuF02_081 but
> our result is not any better than what we've got yesterday. We probably
> ought to refine our implementation.
> Looking at the spectrum we notice that, under the hypothesis that the
> galaxy line is [OIII] 5007, the redshift would be 0.85 -which makes more
> sense if we consider the discovery magnitude of this object- and the match
> to a SN+galaxy wouldn't be worse than that at z=1.48. The prominent
> feature we see at 7450 would land on 4000AA restframe, where a Ia at max
> would peak. The other dips that are less noticiable are in agreement with
> that redshift.
>
> Gastón
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