Re: Some more on GL systematics.

From: Rahman Amanullah (rahman@physto.se)
Date: Mon May 05 2003 - 11:27:13 PDT

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    On Sat, 3 May 2003, Greg Aldering wrote:

    > 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 did the same simulations but with an OM=0.21 universe instead and the
    result was:

    <w> = -0.96 +/- 0.0550 <\Omega_M> = 0.1778 +/- 0.0285

    so the bias was reduced to 0.04 as you more or less predicted. These
    results were obtained from a three parameter fit (\Omega_M, w, \scriptM),
    treating \scriptM as a nuisance parameter and assuming a flat universe. No
    priors were applied.

    Cheers,

      Rahman

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