We extended the work on photometric redshifts of quasars to assign probability density functions (PDFs) in redshift for galaxies and quasars in the SDSS DR5 and GALEX GR3. We find that by selecting quasars with a single peak in their PDF, we are able to reduce the RMS dispersion between photometric and spectroscopic redshift from 0.343 +/- 0.005 to 0.117 +/- 0.010 (errorbars from tenfold cross-validation). We increase the percentage of quasars within 0.3 of the sepctroscopic redshift (a useful criterion for 'catastrophic failure') from 79.8 +/- 0.3% to 99.3 +/- 0.1%.
In future work we intend to generate PDFs for the whole SDSS photometric survey.
Preliminary results were presented as part of a poster presented at the Cosmic Cartography conference in Chicago, Dec 6th 2007. A paper was submitted to ApJ in March 2008 and will be posted to astro-ph when accepted.
Last modified: Mar 27th 2008