From: Serena Nobili (serena@physto.se)
Date: Tue Jan 27 2004 - 07:30:18 PST
Dear Vitaliy,
On Mon, 26 Jan 2004, Vitaliy Fadeyev wrote:
>
>
>Dear Serena,
>
>
>> greater than 1. We could then consider including this information in our
>> paper. However, since this value would not improve the presentation ( e.g.
>> this SN would be even more deviant in the Hubble diagram after correction
>> for the stretch) and given that they could publish the lightcurve at any
>> moment and "perhaps" prove us wrong, I would choose not to modify the
>> analysis presented in the paper, avoiding taking un-necessary risks. I
>
>It seems that this is not an issue of "presentation" per se, but rather
>that of the data analysis. I think that this is your call as to what
>to do in this situation. In principle, you *are* biasing the result,
>if you choose to omit the information which makes the data look "bad".
>At some level, the outliers are to be expected.
>
I am sorry, perhaps I was not too clear about this point. I don't mean to
omit information that makes the data look "bad". My point is rather that
we are not very sure about the information we would like to add. We have
an estimate of the stretch factor which is not really reliable, since it
does not come from the fit of the full data set the other team has for
this supernova. All I am saying is that giving this, I don't feel
comfortable in using that value of the stretch in our paper. Moreover, as
you pointed out (below), this supernova seems slightly under-luminous in
the Hubble diagram, published by Tonry, thus a stretch about 1.1 does not
support this behavior. Note also that even without stretch correction,
this supernova is under-luminous in the I-band Hubble diagram as well.
I hope this clarify my point of view on this issue.
Cheers
Serena
>Another piece of information -- at Gregs suggestion, I also looked at
>the Tonry et all Hubble diagram. Please see the two attached plots;
>they show distance modulus (log(dH)) as a function of log(cz). The 2nd
>plot is a zoomed version of the 1st. The data are taken straight from
>Tonry's compilation (table 8) in the paper.
>In the plots, all SNe are marked blue, except for the 1999Q, which is
>colored green. It seems to be a bit subluminous, i.e. sticking out
>from the average flow by 1.0-1.5 sigma.
>
>Cheers,
>vitaliy
>
>
>
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