From: Lifan Wang (lifan@panisse.lbl.gov)
Date: Mon Mar 22 2004 - 15:47:08 PST
Hi, Chris,
No, my K-Corr are from over 500 real SN spectra. 94D was used for
light curve template.
The difference is caused by the spectral templates - I do not
believe the so called ueber spectra reflects any real SN in the I-band.
The attached figure compares Serena's uber spectrum at day 0 with
a number of around max SNe.
Cheers,
Lifan
On Sun, 21 Mar 2004, Chris Lidman wrote:
> Dear Lifan,
> Can you plot the spectra that you use to derive k-corrections against Serena's. template
> spectra. Perhaps we will understand the differences between your k-corrections and Serena's
> by examining such plots. From the title of the PostScript plots, I infer that your corrections
> are derived from a single supernova - 94D. Is this correct?
>
> Cheers, Chirs.
>
> Chris Lidman wrote:
>
> > Hi Lifan,
> > Yes, I did get my signs wrong and you are correct.
> >
> > Chris.
> >
> > On Fri, 2004-03-19 at 12:52, Lifan Wang wrote:
> > > >
> > > > If one examines Serena's Hubble diagram then the evidence
> > > > for such an offset between z=0.01 and z=0.05 SNe is slight,
> > > > and, if I have my k correction signs correct, then
> > > > Lifan's k-corrections - being more positive than Serena's -
> > > > would make the z=0.05 SNe fainter, i.e. it would move the
> > > brighter ?
> > >
> > > > z=0.05 SNe (all from the Hamuy sample) further away form the
> > > > Hubble line.
> > > >
> > > > Cheers, Chris.
> > > >
> > > >
> > > > On Wed, 2004-03-17 at 00:25, Lifan Wang wrote:
> > > > > Reporting-MTA: dns; venezia.lbl.gov
> > > > > Arrival-Date: Tue, 16 Mar 2004 20:23:13 -0800
> > > > >
> > > > > Final-Recipient: RFC822; scpexec@panisse.lbl.gov
> > > > > Action: failed
> > > > > Status: 5.1.1
> > > > > Remote-MTA: DNS; zacharys.lbl.gov
> > > > > Diagnostic-Code: SMTP; 550 5.1.1 <scpexec@panisse.lbl.gov>... User unknown
> > > > > Last-Attempt-Date: Tue, 16 Mar 2004 20:23:13 -0800
> > > > >
> > > > > ______________________________________________________________________
> > > > >
> > > > > From: Lifan Wang <lifan@venezia.lbl.gov>
> > > > > To: saul@lbl.gov, scpexec@panisse.lbl.gov
> > > > > Subject: Re: K-corrections: another voice in the debate (fwd)
> > > > > Date: 16 Mar 2004 20:23:13 -0800
> > > > >
> > > > > Dear All,
> > > > >
> > > > > Here is my version of the I-band k corrections comapred to
> > > > > Serena's. My version is considerable different from both of Serena's and
> > > > > Alex's.
> > > > >
> > > > > There is a simple way to check whose is more reasonable. The
> > > > > I-band should be very well approximated by a Rayleigh-Jeans law,
> > > > > expecially before/around optical max, in which case the K-correction can
> > > > > be calculated analytically. Of course, spectral lines can make it
> > > > > complicated. Some SNe line 91T do not have strong lines in the I-band.
> > > > >
> > > > > The lines in the attached figures are:
> > > > >
> > > > > Black: the median values of the K-corrections I calculated
> > > > > Green: Serena's K-corrections
> > > > > Red: 1 sigma standard deviations from the black line
> > > > > Blue: The blackbody limit
> > > > >
> > > > > The last figure gives the k-correction as a function of color.
> > > > >
> > > > > I guess the differences are substantial, and some serious efforts
> > > > > are needed to get it right. However, I am okey if you want to blame the
> > > > > uncertainties of I-band templates as the cause for the differences.
> > > > >
> > > > > Cheers,
> > > > >
> > > > > Lifan
> > > >
>
-- Lifan Wang (510) 495 2733 (o) (510) 704 0119 (h)
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