From: Reynald Pain (Reynald.Pain@in2p3.fr)
Date: Fri May 02 2003 - 06:02:38 PDT
Hi,
Concerning 1998ay/98104 and 1998be/9878. Judging from figure 1+2, it
is not obvious that their lightcurve are well fit with the Ia template.
Look at the points near max of the R LC (only past max data in I).
Reynald
_____________________________________________________________________
R. Pain - LPNHE, Universites Paris VI & VII, 4 Place Jussieu - T33 RdC
75252 Paris cedex 05 - Tel: +33 1 44 27 72 53 Fax: +33 1 44 27 46 38
On Thu, 1 May 2003, Peter Nugent wrote:
> > We have to make sure we don't get into circular arguments while
> > eg first using colors to type it, and then use same colors to
> > limit reddening.
>
> Fortunately for us SNe Ia are much bluer than Ib/c's and their color
> evolution is different as well so reddening and typing isn't a
> circular task.
>
> Now as for Rob's statement about the categories these should fall in.
>
> The color of a Ib/c at this z should be R-I>=0.8 before peak and it gets
> redder continuously. A Ia should have a color around R-I>=0.3-0.4 with a
> little slop due to choice of uberspectrum and stretch (a bluer one like
> Rob used for all his analysis makes it around 0.3, what I and the Israelis
> used puts it around 0.4) and the color curves are very different. Your
> measurements of the color (including all possible arbitrary systematics,
> like using both uberspectra for the k-corrs) for these SNe are better than
> 0.1 mag. Thus according to the paper I cited (and their nice interactive
> website) and what I checked out on my own, the colors and their evolution
> are consistent with them both being Ia's at => 3 sigma. As Rob pointed
> out, they fit his Ia color curves nicely.
>
> Thus they should definitely go into the 'good' Ia category, because I
> think this is at the same level as the id'ing of the spectra as 'good'.
> And remember, the spectra are not-inconsistent with Ia's, they are just
> not that good S/N-wise, so there is no negative from them, just no
> positive either.
>
> Now before Saul says, 'Why don't we do this for the other SNe from P99 we
> threw out?' the simple answer is we can't since we in general have just 1
> color at peak (not 4-5 spread out) and their error bars on that 1 color
> are horrendous.
>
> Thus add my paragraph in where you id them and we are good to go as-is.
>
> Cheers,
>
> Peter
>
> --
> Peter E. Nugent
> Staff Computational Scientist - Scientific Computing Group - NERSC
> Lawrence Berkeley National Laboratory
> M.S. 50F-1650 - 1 Cyclotron Road - Berkeley, CA, 94720-8139
> Phone:(510) 486-6942 - Fax:(510) 486-5812
> E-mail: penugent@LBL.gov - Web: http://supernova.LBL.gov/~nugent
>
>
>
>
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