From: Andy Howell (howell@astro.utoronto.ca)
Date: Mon Mar 08 2004 - 12:53:48 PST
Chris,
I have mande several improvements to my program recently, most notably
better outlier rejection and better handling of error spectra, so it
certainly is worth rerunning objects for which we have questions. In these
plots, blue is the rebinned spectrum after host galaxy subtraction
(usually 5 A binning for these plots), black is the low-z template, and
green is the original data.
I have attached 5 postscript plots of the best fits to the 4 SNe you sent.
> S01-004 - currently classified as ?
Rerun with no host. The fit here shows a comparison to SN 1993J at +17d
at z=0.41 (z is not known from the host). The fit isn't that bad. Do we
know the date our spectrum was taken with respect to maximum light? I'm
sure +17d is too late, but these IIb's have different features come in at
different times depending on the relative thicknesses of the H and He
envelopes. I wouldn't say that it is either a II or Ib for certain, but I
think it is unlikely that it is a Ia. How about (IIb?) for the
classification?
> S01-028 - currently classified as ?
> Significant host contamination. The percentage increase is only 27%.
> Previously, we had this one as Ia?
As you say, the host contamination is pretty bad. Here I show a
comparison to SN 1999ee (Ia) at -8d after subtraction of an SB6 host
galaxy. I find it very unconvincing. CaII should be obvious but is
not. Still "?" as far as I'm concerned.
> C02-028 - currently classified as ?
> Another one with significant host contamination. The percentage increase
> is only 13%.
C02-028_spec.1.ps shows the comparison to SN 1999aa at -1d.
The blue side looks ok, and it is possible that the feature at 9000A is Si
6150. The problem with this interpretation is that the SII "W" at rest
5400A should be there, but it isn't! Neither is the "emission" (really
lack of absorption) just blueward of it at rest 5100A.
C02-028_spec.18.ps shows a comparison to SN 1987K (II) at +7d after some
serious host galaxy subtraction and mangling of the color. I don't
believe it either, but it shows the difficulty in narrowing down the type.
> SuF02-002 - currently classified as ?
> This one has some host contamination. Previously we had Ia?
Ugh. This one is disgusting. About the only thing I can say is that it
is not inconsistent with a Ia. But on the other hand, there isn't
anything to make me believe it is a Ia either!
-Andy
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