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The 2dF Galaxy Redshift Survey: correlation functions, peculiar velocities and the matter density of the Universe

Ed HawkinsSchool of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RDS. MaddoxSchool of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RDShaun ColeDepartment of Physics, University of Durham, South Road, Durham DH1 3LEO. LahavInstitute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HADarren S. MadgwickDepartment of Astronomy, University of California at Berkeley, Berkeley, CA 94720, USAP. NorbergDepartment of Physics, University of Durham, South Road, Durham DH1 3LEJ. A. PeacockInstitute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJI. K. BaldryDepartment of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218-2686, USAC. M. BaughDepartment of Physics, University of Durham, South Road, Durham DH1 3LEJoss Bland‐HawthornAnglo-Australian Observatory, PO Box 296, Epping, NSW 2121, AustraliaTerry BridgesAnglo-Australian Observatory, PO Box 296, Epping, NSW 2121, AustraliaR. CannonAnglo-Australian Observatory, PO Box 296, Epping, NSW 2121, AustraliaMatthew CollessResearch School of Astronomy and Astrophysics, The Australian National University, Weston Creek, ACT 2611, AustraliaC. CollinsAstrophysics Research Institute, Liverpool John Moores University, Twelve Quays House, Birkenhead L14 1LDW. CouchDepartment of Astrophysics, University of New South Wales, Sydney, NSW 2052, AustraliaGavin DaltonDepartment of Physics, University of Oxford, Keble Road, Oxford OX1 3RHR. de ProprisDepartment of Astrophysics, University of New South Wales, Sydney, NSW 2052, AustraliaSimon P. DriverResearch School of Astronomy and Astrophysics, The Australian National University, Weston Creek, ACT 2611, AustraliaG. EfstathiouInstitute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HAR. S. EllisDepartment of Astronomy, California Institute of Technology, Pasadena, CA 91125, USACarlos S. FrenkDepartment of Physics, University of Durham, South Road, Durham DH1 3LEKarl GlazebrookDepartment of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218-2686, USACarole JacksonResearch School of Astronomy and Astrophysics, The Australian National University, Weston Creek, ACT 2611, AustraliaJ. B. JonesSchool of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RDIan LewisDepartment of Physics, University of Oxford, Keble Road, Oxford OX1 3RHS. L. LumsdenDepartment of Physics, University of Leeds, Woodhouse Lane, Leeds LS2 9JTWill J. PercivalInstitute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJB. A. PetersonResearch School of Astronomy and Astrophysics, The Australian National University, Weston Creek, ACT 2611, AustraliaWill SutherlandInstitute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJK. TaylorDepartment of Astronomy, California Institute of Technology, Pasadena, CA 91125, USA

2003en

ABI

Annotatsiya

We present a detailed analysis of the two-point correlation function, ξ(σ, π) , from the 2dF Galaxy Redshift Survey (2dFGRS). The large size of the catalogue, which contains ∼220 000 redshifts, allows us to make high-precision measurements of various properties of the galaxy clustering pattern. The effective redshift at which our estimates are made is zs≈ 0.15 , and similarly the effective luminosity, Ls≈ 1.4L* . We estimate the redshift-space correlation function, ξ(s) , from which we measure the redshift-space clustering length, s0= 6.82 ± 0.28 h−1 Mpc . We also estimate the projected correlation function, Ξ(σ) , and the real-space correlation function, ξ(r) , which can be fit by a power law (r/r0)−γr , with r0= 5.05 ± 0.26 h−1 Mpc, γr= 1.67 ± 0.03 . For r≳ 20 h−1 Mpc, ξ drops below a power law as, for instance, is expected in the popular Λ cold dark matter model. The ratio of amplitudes of the real- and redshift-space correlation functions on scales of 8– 30 h−1 Mpc gives an estimate of the redshift-space distortion parameter β. The quadrupole moment of ξ(σ, π) on scales 30– 40 h−1 Mpc provides another estimate of β. We also estimate the distribution function of pairwise peculiar velocities, f(v), including rigorously the significant effect due to the infall velocities, and we find that the distribution is well fit by an exponential form. The accuracy of our ξ(σ, π) measurement is sufficient to constrain a model, which simultaneously fits the shape and amplitude of ξ(r) and the two redshift-space distortion effects parametrized by β and velocity dispersion, a. We find β= 0.49 ± 0.09 and a= 506 ± 52 km s−1 , although the best-fitting values are strongly correlated. We measure the variation of the peculiar velocity dispersion with projected separation, a(σ), and find that the shape is consistent with models and simulations. This is the first time that β and f(v) have been estimated from a self-consistent model of galaxy velocities. Using the constraints on bias from recent estimates, and taking account of redshift evolution, we conclude that β (L=L*, z= 0) = 0.47 ± 0.08 , and that the present-day matter density of the Universe, Ωm≈ 0.3 , consistent with other 2dFGRS estimates and independent analyses.

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DOI: 10.1046/j.1365-2966.2003.07063.x

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