The 2dF QSO Redshift Survey – XI. The QSO power spectrum
Authors: Outram P.J.1; Hoyle F.2; Shanks T.1; Croom S.M.3; Boyle B.J.3; Miller L.4; Smith R.J.5; Myers A.D.1
Source: Monthly Notices of the Royal Astronomical Society, Volume 342, Number 2, June 2003 , pp. 483-495(13)
Publisher: Blackwell Publishing
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Abstract:
We present a power spectrum analysis of the final 2dF Quasi-Stellar Object (QSO) Redshift Survey catalogue containing 22 652 QSOs. Utilizing the huge volume probed by the QSOs, we can accurately measure power out to scales of
500 h-1 Mpc and derive new constraints, at z 1.4 , on the matter and baryonic contents of the Universe. Importantly, these new cosmological constraints are derived at an intermediate epoch between the cosmic microwave background observations at z 1000 , and local (z 0) studies of large-scale structure; the average QSO redshift corresponds to a look-back time of approximately two-thirds of the age of the Universe. We find that the amplitude of clustering of the QSOs at z 1.4 is similar to that of present-day galaxies. The power spectra of the QSOs at high and low redshift are compared and we find little evidence for any evolution in the amplitude. Assuming a 
cosmology to derive the comoving distances, r(z) , to the QSOs, the power spectrum derived can be well described by a model with shape parameter 
= 0.13 ± 0.02 . If an Einstein–de Sitter model r(z) is instead assumed, a slightly higher value of = 0.16 ± 0.03 is obtained. A comparison with the Hubble Volume cold dark matter (CDM) simulation shows very good agreement over the whole range of scales considered. A standard (
m= 1) CDM model, however, predicts a much higher value of than is observed, and it is difficult to reconcile such a model with these data. We fit CDM model power spectra (assuming scale-invariant initial fluctuations), convolved with the survey window function, and corrected for redshift space distortions, and we find that models with baryon oscillations are slightly preferred, with the baryon fraction b/m= 0.18 ± 0.10 . The overall shape of the power spectrum provides a strong constraint on mh (where h is the Hubble parameter), with mh= 0.19 ± 0.05 .
Keywords: surveys; quasars: general; cosmology: observations; large-scale structure of Universe
Document Type: Research article
DOI: 10.1046/j.1365-8711.2003.06527.x
Affiliations: 1: Department of Physics, Science Laboratories, South Road, Durham, DH1 3LE 2: Department of Physics, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, USA 3: Anglo-Australian Observatory, PO Box 296, Epping, NSW 2121, Australia 4: Department of Physics, Oxford University, Keble Road, Oxford, OX1 3RH 5: Liverpool John Moores University, Twelve Quays House, Egerton Wharf, Birkenhead, CH41 1LD
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