From: Peter Nugent (nugent@panisse.lbl.gov)
Date: Thu Feb 27 2003 - 13:31:27 PST
> I'm going to apply this to his dm15 fits. What I still don't understand
> is just *how* the hell he used it. Here's what I think I know. He's
> got an mb and an mv; from this he gets an E(B-V). He generates a highly
> asymmetric error bar on E(B-V) which has a non-gaussian shape by
> multiplying his measurement error (assumed to be gaussian) by this
> prior.
So far so good.
> What next? Does he *move* E(B-V) to the new value based on the prior?
> (I.e., this prior is going to generate a probability distribution
> function whose peak is offset from the old center.) If so, then he's
> reddening *everything*, which is at odds with his list of AB=0 for most
> of his supernovae. How does he use it? What did he do?
As far as I know, from e-mail almost 5 years old, he takes his new E(B-V)
from the peak value and then computes the second moment of the
distribution to figure out the size of his uncertainty. Attached is a
piece of idl code from June of '98 which shows how he does it.
Good luck,
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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