231 citations · 770 across the 13 of their papers we have counts for
4 papers · 1 filter
Interpreting the Ionization Sequence in AGN Emission-Line Spectra
Chris T. Richardson, James T. Allen, Jack A. Baldwin +2
We investigate the physical cause of the great range in the ionization level seen in the spectra of narrow lined active galactic nuclei (AGN). Mean field independent component anal…
Quasar broad absorption line variability measurements using reconstructions of un-absorbed spectra
Conor Wildy, Michael R. Goad, James T. Allen
We present a two-epoch Sloan Digital Sky Survey and Gemini/GMOS+William Herschel Telescope/ISIS variability study of 50 broad absorption line quasars of redshift range 1.9 < z < 4.…
Classification and analysis of emission-line galaxies using mean field independent component analysis
James T. Allen, Paul C. Hewett, Chris T. Richardson +2
We present an analysis of the optical spectra of narrow emission-line galaxies, based on mean field independent component analysis (MFICA). Samples of galaxies were drawn from the…
A strong redshift dependence of the broad absorption line quasar fraction
James T. Allen, Paul C. Hewett, Natasha Maddox +2
We describe the application of non-negative matrix factorisation to generate compact reconstructions of quasar spectra from the Sloan Digital Sky Survey (SDSS), with particular ref…