2dF QSO Redshift Survey (2QZ) Results

2QZ Results

This is simply to be a grab bag of recent preliminary results, plots and points of interest which we want to make public. Unless stated otherwise, anything which appears here should be considered a work in progress. For actual published results, please see our list of 2QZ publications.

Example Spectra

See also Whole Survey Stacks below

From our first observing run.
QSOs in the rest frame. This PS plot and this gif version show ten QSOs at various redshifts each projected back to its rest wavelength and then compared with a composite spectrum. They demonstrate how we observe a different section of the QSO spectrum depending on its redshift. For very distant objects the ultra-violet part of the spectrum has been redshifted into the visible and is what we observe. For very low redshift QSOs, we can actually observe the visible wavelengths. The composite at the bottom of the figure was created by adding together 10000 spectra, thereby creating one mean spectrum which covers the full wavelength range. The ten spectra are available individually, in their observed frame below.
Various example spectra in gif and PS formats.
Postscript plot of some QSOs and galaxies taken from an AAO Newsletter article.

QSO Clustering

This is currently an area of very active work and we hope new results will appear here soon. For the time being, we suggest you look at the on-line version of the talk Scott Croom gave at the 1999 Coral Sea Cosmology meeting. Please bear in mind though that this is still a work in progress and it would be best not to quote results presented here without first talking to the authors.

Luminosity Function

The survey's impact is not restricted to cosmology. The luminosity function, (i.e., the abundance of QSOs as a function of their luminosity or intrinsic brightness) is an important way of parameterising the population. Any model seeking to describe QSO formation and fuelling mechanisms must be able to reproduce the observed population and its evolution with redshift. The 2QZ has allowed the measurement of QSO evolution in unprecedented detail. The accompanying figure shows the optical luminosity function (OLF) for ten separate data subsets divided by redshift. The evolution as a function of redshift is obvious and over the redshift range 0·35 < z < 2·3 is acceptably fit by pure luminosity evolution (PLE). That is, the form of the OLF does not vary with redshift, but is simply shifted to higher luminosity. The shape and evolution at low redshifts (z<0·5) and high luminosities are not currently well sampled by the 2QZ, but may show departures from PLE. We hope to address this issue in more detail with the complete 2QZ catalogue, supplemented with our own FLAIR/6dF QSO survey.

The OLF results are published in The 2dF QSO Redshift Survey - I. The Optical Luminosity Function, B.J. Boyle, T, Shanks, S.M. Croom, R.J. Smith, L. Miller, N. Loaring, C. Heymans, MNRAS accepted, astro-ph/0005368

Number Counts