From: Greg Aldering (aldering@panisse.lbl.gov)
Date: Wed Apr 30 2003 - 20:33:24 PDT
Just for clarification, my statement about throwing out restframe
wavelengths < 4000A was based on the new 3A-binned fit to SN1980K at +7
days. In the case of the original fit we discussed - that to SN1984E at +4
days, with 20A binning and which *does* extend well below restframe 4000A,
I still don't see how the 4000A break - which is so apparent in Isobel's
spectrum - disappears in yours. Forgive me if I'm misunderstanding
something here.
- Greg
On Wed, 30 Apr 2003, Andy Howell wrote:
> Greg,
> This mainly a psychological effect of the rebinning -- I rebinned the
> data to 20A.
> I put up on the web page the same plot rebinned to 3A -- you can see it
> looks like the
> untouched data.
>
> Also, the spectrum I show is cropped to only show where the template
> spectrum and
> the observation overlap. I put up another plot showing a different fit
> with more of the data.
>
> My program has the freedom to do other things to the data as well. In
> my plots I have alread
> subtracted host galaxy. Plus, my program either reddens or bluens the
> spectrum to find the best fit.
>
> So the spectrum I show may not correspond to reality -- I let it mangle
> the observed
> spectrum to find the best fit possible. Often it will find junk, but
> the point is that
> if there is a Ia signal there it should find it. Here I just chose one
> example to show,
> but I don't believe it -- I don't believe any of the fits.
>
> -Andy
>
> Greg Aldering wrote:
>
> >Hi Andy,
> >
> >I am looking at the spectral fits to 98104 on your website. I don't see a
> >relation between your spectrum and Isobel's. Am I even looking at the
> >right thing? (Yours is labeled "Observed: 98104cc_comb.Ic.asc" and
> >Isobel's is labeled "98104 (Keck) : 98104cc_comb.asc". Yours is a
> >power law and Isobel's have plenty of wriggles.
> >
> >
> >
> >>Due to the E's 4000A break, you subtrack off more light blueward of 4000A
> >>than redward, and this can mimic Ca from the SN.
> >>
> >>
> >
> >No. The effect of subtracting an elliptical is to decrease the strength
> >of Ca - unless you let the elliptical go negative! But I do agree that
> >9878 isn't convincing.
> >
> >- Greg
> >
> >
> >
>
>
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