From: Rahman Amanullah (rahman@physto.se)
Date: Mon May 05 2003 - 04:24:41 PDT
On Sat, 3 May 2003, Greg Aldering wrote:
> I have a few questions related to these GL simulations. First, the
> values you give below are the shifts for the SN data by themselves,
> right? If the w and OM shifts are correlated, then probably the priors
> from CMB and 2dFGRS will limit the overall effect. Has this been
> included? Since the w value we quote includes the other priors, they
> have to be considered somehow in calculating a systematic uncertainty on
> that value of w. Since, as Rob has noted, the GL effects might be the
> largest of all the systematics, the w systematics error might be set by
> your treatment.
No, the above mentioned priors were not considered in our results. It
would however be fairly easy to do so. Rob if you want to take a look at
it, I have put the results from our grid fits on:
http://www.physto.se/~rahman/hstbias/
Otherwise, you could send med the priors for WMAP and 2dFGRS, if you have
them as a matrix or something similiar and I could do it. Perhaps this
would be easier?
> Also, given that you set Omega MACHO to 20% of OM, would the size of the
> bias shrink by roughly 2/3's if you modeled an OM=0.21 universe, i.e.,
> to match our observations? This would reduce the bias on w to about
> 0.05. Also, as you know, the w sensitivity can change a lot depending on
> how the other parameters are set.
We are looking in to this, meaning we are doing some simulations with
OM=0.21 and we will let you know as soon as we have some results.
Cheers,
Rahman
__________________________________________________________
Rahman Amanullah, +46 8 553 786 61
Stockholm University ICQ: 62860758
Stockholm Centre for Physics, 17d 50m E
Astronomy & Biotechnology 59d 26m N
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