From: Lifan Wang (lifan@panisse.lbl.gov)
Date: Tue May 07 2002 - 10:35:24 PDT
First, I don't think I 91T-like are less extincted, on the contrary all
observational evidences (light echoes, association with younger populations ...)
point to very high extinction for these events. The CMAGIC methods that
Gerson and I are working on also suggests strongly that they syffer the
heaviest extinction among all Ia.
Now that you asked, for R_B = 4.1, I derived A_v around 2. But I would not bet
heavily on that considering slit losses and other uncertainties.
The 5000A feature Peter mentioned might be there, but with low S/N.
Lifan
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> To: Saul Perlmutter <saul@lbl.gov>
> cc: deepnews@lbl.gov, Lifan Wang <LWang@lbl.gov>
> Subject: Re: Lifan's also thinking early SN, but 91T-like...[Fwd: [Fwd:
> C02-016 - aka VotezChirax]]
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>
> > Here's what Lifan's program fit. I guess the main interesting thing
> > here is that it independently found the same redshift (for a 91T-like SN
> > Ia about a week before max) as the redshift of the OII line that Chris
> > reported a hint of. Have a look particularly at the last of the three
> > spectrum links that Lifan's email points to.
>
> Yes, that is consistent with what I said. 91T-like Ia's and Ib/c's do look
> a lot like each other. Unfortunately it doesn't look like there is a lot
> of extinction for this SN, the spectrum looks too blue. Also t is missing
> a prominent 91 feature at 5000 Ang restframe. As Lifan said a bluer
> spectrum would be nicer to figre this out. Given how faint it is I doubt
> it's a 91T since I don't see the extinction. Another spectrum would be
> nice but I don't know if we have the time to do that.
>
>
> > Peter had recently convinced us that 91T's don't necessarily have lots
> > of extinction -- but I guess it doesn't mean that this one couldn't have
> > extinction. Lifan, did your fit also give a best-fit extinction? (Of
> > course, this may be off, because it depends on what extinction is
> > attributed to the 91T template.)
>
> Peter who? Not this Peter, since the only 91T's I've seen are quite
> extinguished. I've looked at 5 of them and they were all effected by
> dust, 91T is one of the ones LEAST effected by dust of this class...
> Given that the spectrum is flux calibrated it sort of lies right on the
> unextingushed 91T spectrum I have at -7 days. It is 1.0 mag fainter at
> this epoch than 91T would be at this z. I wouldn't bother with more obs,
> other than the rolling photometry, unless we have time to kill.
>
>
>
> Cheers,
>
> Peter
>
>
> --
> Peter E. Nugent
> Computer Scientist - Scientific Computing Group - NERSC
> Lawrence Berkeley National Laboratory
> M.S. 50F - 1 Cyclotron Road - Berkeley, CA, 94720
> Phone:(510) 486-6942 - Fax:(510) 486-5812
> E-mail: penugent@LBL.gov - Web: http://supernova.LBL.gov/~nugent
>
>
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