Thursday 31 December 2009

Fitting of models of radio spectra -- talk at NRAO/Green Bank

I gave a talk today at NRAO/Green Bank on the fitting of models of radio
spectra. The PDF of the talk is available at:

http://www.mrao.cam.ac.uk/~bn204/publications/2009/specbasic.pdf

While the full detail on the method is available in this paper:

http://www.mrao.cam.ac.uk/~bn204/publications/2009/specanalysis.pdf

Monday 14 December 2009

Fitting and Comparison of Models of Radio Spectra

I've put a paper on this topic on ArXiv, here is the abstract:

I describe an approach to fitting and comparison of radio spectra based
on Bayesian analysis and realised using a new implementation of the
nested sampling algorithm. Such an approach improves on the commonly
used maximum-likelihood fitting of radio spectra by allowing objective
model selection, calculation of the full probability distributions of
the model parameters and provides a natural mechanism for including
information other than the measured spectra through priors. I this
paper I cover the theoretical background, the algorithms used and the
implementation details of the computer code. I also briefly illustrate
the method with some previously published data for three near-by
galaxies. In forthcoming papers we will present the results of applying
this analysis larger data sets, including some new observations, and the
physical conclusions that can be made. The computer code as well as the
overall approach described here may also be useful for analysis of other
multi-chromatic broad-band observations and possibly also photometric
redshift estimation. All of the code is publicly available, licensed
under the GNU General Public License, at
http://www.mrao.cam.ac.uk/~bn204/galevol/speca/index.html.

As always, the paper is available from the publications list at:

http://www.mrao.cam.ac.uk/~bn204/publications/publicationlist.html