The WiggleZ Dark Energy Survey: small‐scale clustering of Lyman‐break galaxies at z < 1

Department of Physics & Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC, Canada V6T 1Z1
Monthly Notices of the Royal Astronomical Society (Impact Factor: 5.23). 04/2009; 395(1):240 - 254. DOI: 10.1111/j.1365-2966.2009.14447.x
Source: arXiv

ABSTRACT The WiggleZ Dark Energy Survey is a large-scale structure survey of intermediate-redshift ultraviolet-selected (UV-selected) emission-line galaxies scheduled to cover 1000 deg2, spanning a broad redshift range 0.2 < z < 1.0. The main scientific goal of the survey is the measurement of baryon acoustic oscillations (BAO) in the galaxy clustering pattern at a significantly higher redshift than previous studies. The BAO may be applied as a standard cosmological ruler to constrain dark energy models. Based on the first 20 per cent of the data set, we present initial results concerning the small-scale clustering of the WiggleZ targets, together with survey forecasts. The WiggleZ galaxy population possesses a clustering length r0= 4.40 ± 0.12 h−1 Mpc, which is significantly larger than z= 0 UV-selected samples, with a slope γ= 1.92 ± 0.08. This clustering length is comparable to z= 3 Lyman-break galaxies with similar UV luminosities. The clustering strength of the sample increases with optical luminosity, UV luminosity and reddening rest-frame colour. The full survey, scheduled for completion in 2010, will map an effective volume Veff≈ 1 Gpc3 (evaluated at a scale k= 0.15 h Mpc−1) and will measure the angular diameter distance and Hubble expansion rates in three redshift bins with accuracies of ≈5 per cent. We will determine the value of a constant dark energy equation-of-state parameter, wcons, with a higher precision than existing supernovae observations using an entirely independent technique. The WiggleZ and supernova measurements lie in highly complementary directions in the plane of wcons and the matter density Ωm. The forecast using the full combination of WiggleZ, supernova and cosmic microwave background (CMB) data sets is a marginalized error Δwcons= 0.07, providing a robust and precise measurement of the properties of dark energy including cross-checking of systematic errors.

  • [Show abstract] [Hide abstract]
    ABSTRACT: We present a simple and efficient phenomenological model for the two-dimensional two-point galaxy correlation function that works well over a wide range of scales, from large scales down to scales as small as 25 h-1 Mpc. Our model incorporates non-linear effects and a scale-dependent galaxy bias on small scales, and it allows the redshift-space distortions to be scale and direction dependent. We validate our model using LasDamas mock catalogues and apply it to the Sloan Digital Sky Survey (SDSS) Data Release Seven (DR7) luminous red galaxies (LRGs). Using only the monopole and quadrupole of the correlation function measured from the SDSS DR7 LRGs, we obtain improved measurements H(z)rs(zd)/c = 0.0433 ± 0.0042, DA(z)/rs(zd) = 6.59 ± 0.46 and f (z)σ8(z) = 0.429 ± 0.089 at z = 0.35, using the scale range 25 < s < 120 h-1 Mpc. We expect our results and model to be useful in tightening dark energy and gravity constraints from the full analysis of current and future galaxy clustering data.
    Monthly Notices of the Royal Astronomical Society 10/2013; 435(1):255-262. DOI:10.1093/mnras/stt1290 · 5.23 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We present an analysis of the clustering of galaxies from z ~ 2 to the present day using the WIRCam Deep Survey (WIRDS). WIRDS combines deep near-infrared data with the deep optical data from the CFHTLS Deep fields, providing a photometric data-set over an effective area of 2.4 sq. deg., from which accurate photometric redshifts and stellar masses can be estimated. We use the data to calculate the angular correlation function for galaxy samples split by star-formation activity, stellar mass and redshift. We estimate the real-space clustering for each sample, determining clustering lengths and power-law slopes. For galaxies selected by constant mass, we find that the clustering scale shows no evolution up to z ~ 2. Splitting the galaxy sample by mass, we see that higher mass galaxies have larger clustering scales at all redshifts. We use our results to test the GALFORM semi-analytical galaxy formation model and find the two are consistent. We split the galaxy population into passive and star-forming populations and find that the passive galaxy population shows a significantly larger clustering scale at all redshifts than the star-forming population below masses of ~$10^{11}M_\odot/h$, showing that even at z ~ 2 passive galaxies exist in denser environments than the bulk of the star-forming galaxy population. For star-forming galaxies with stellar masses $>10^{11}M_\odot/h$, we find a clustering strength of ~8Mpc/h across all redshifts, comparable to the measurements for the passive population. Also, for star-forming galaxies we see that clustering strength increases for higher stellar mass systems, however there is little sign of a mass dependence in passive galaxies. Finally, we investigate the connection between galaxy stellar mass and dark matter halo mass, showing a clear correlation between the two in both the WIRDS data and the GALFORM predictions.
    Astronomy and Astrophysics 10/2013; 568. DOI:10.1051/0004-6361/201322814 · 4.48 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The anisotropic galaxy clustering on large scales provides us with a unique opportunity to probe into the gravity theory through the redshift-space distortions (RSDs) and the Alcock-Paczynski effect. Using the multipole power spectra up to hexadecapole, of the Luminous Red Galaxy (LRG) sample in the data release 7 (DR7) of the Sloan Digital Sky Survey II (SDSS-II), we obtain simultaneous constraints on the linear growth rate f, angular diameter distance D_{A}, and Hubble parameter H at redshift z = 0.3. For this purpose, we first extensively examine the validity of a theoretical model for the non-linear RSDs using mock subhalo catalogues from N-body simulations, which are constructed to match with the observed multipole power spectra. We show that the input cosmological parameters of the simulations can be recovered well within the error bars by comparing the multipole power spectra of our theoretical model and those of the mock subhalo catalogues. We also examine systematic uncertainties in our analysis by testing the dependence on prior assumption of the theoretical model and the range of wavenumbers to be used in the fitting. These investigations validate that the theoretical model can be safely applied to the real data. Thus, our results from the SDSS DR7 LRG sample, f (z = 0.3) =0.71 +- 0.12, D_{A} (z = 0.3) =968 +- 42[Mpc], H (z = 0.3) =81.7 +- 5.0[km/s/Mpc], are robust against such systematics of theoretical modeling. We believe that our method to constrain the cosmological parameters using subhaloes catalogues will be useful for more refined samples like CMASS and LOWZ catalogues in the Baryon Oscillation Spectroscopic Survey in SDSS-III.
    Monthly Notices of the Royal Astronomical Society 10/2013; 439(3). DOI:10.1093/mnras/stu111 · 5.23 Impact Factor

Full-text (4 Sources)

Available from
May 19, 2014