Institution
Institute of Cosmology and Gravitation, University of Portsmouth
About: Institute of Cosmology and Gravitation, University of Portsmouth is a based out in . It is known for research contribution in the topics: Galaxy & Redshift. The organization has 297 authors who have published 1207 publications receiving 76919 citations.
Topics: Galaxy, Redshift, Dark energy, Dark matter, Cosmic microwave background
Papers published on a yearly basis
Papers
More filters
••
TL;DR: In this article, the impact of the sample geometry, non-linear processes and biases induced by our lack of understanding of the radial galaxy distribution on RSD measurements was investigated using Large Suite of Dark Matter Simulations of the Sloan Digital Sky Survey II (SDSS-II) luminous red galaxy data.
Abstract: The simplest theory describing large-scale redshift-space distortions (RSD), based on linear theory and distant galaxies, depends on the growth of cosmological structure, suggesting that strong tests of general relativity can be constructed from galaxy surveys. As data sets become larger and the expected constraints more precise, the extent to which the RSD follow the simple theory needs to be assessed in order that we do not introduce systematic errors into the tests by introducing inaccurate simplifying assumptions. We study the impact of the sample geometry, non-linear processes and biases induced by our lack of understanding of the radial galaxy distribution on RSD measurements. Using Large Suite of Dark Matter Simulations of the Sloan Digital Sky Survey II (SDSS-II) luminous red galaxy data, these effects are shown to be important at the level of 20 per cent. Including them, we can accurately model the recovered clustering in these mock catalogues on scales 30–200 h−1 Mpc. Applying this analysis to robustly measure parameters describing the growth history of the Universe from the SDSS-II data gives f(z= 0.25)σ8(z= 0.25) = 0.3512 ± 0.0583 and f(z= 0.37)σ8(z= 0.37) = 0.4602 ± 0.0378 when no prior is imposed on the growth rate, and the background geometry is assumed to follow a Λ cold dark matter (ΛCDM) model with the Wilkinson Microwave Anisotropy Probe (WMAP)+Type Ia supernova priors. The standard WMAP constrained ΛCDM model with general relativity predicts f(z= 0.25)σ8(z= 0.25) = 0.4260 ± 0.0141 and f(z= 0.37)σ8(z= 0.37) = 0.4367 ± 0.0136, which is fully consistent with these measurements.
395 citations
••
Institut d'Astrophysique de Paris1, Lawrence Berkeley National Laboratory2, University of Chile3, University of Zurich4, Centre national de la recherche scientifique5, Apache Corporation6, University of Florida7, University of Barcelona8, University of Wyoming9, Institute of Cosmology and Gravitation, University of Portsmouth10, Pennsylvania State University11, University of Chicago12
TL;DR: The first results from an ongoing survey for damped Lyman-α systems (DLAs) in the spectra of z ǫ > 2 quasars observed in the course of the Baryon Oscillation Spectroscopic Survey (BOSS) as mentioned in this paper, which is part of the Sloan Digital Sky Survey (SDSS) III.
Abstract: We present the first results from an ongoing survey for damped Lyman-α systems (DLAs) in the spectra of z > 2 quasars observed in the course of the Baryon Oscillation Spectroscopic Survey (BOSS), which is part of the Sloan Digital Sky Survey (SDSS) III. Our full (non-statistical) sample, based on Data Release 9, comprises 12 081 systems with log N (H i) ≥ 20, out of which 6839 have log N (H i) ≥ 20.3. This is the largest DLA sample ever compiled, superseding that from SDSS-II by a factor of seven. Using a statistical sub-sample and estimating systematics from realistic mock data, we probe the N (H i) distribution at ⟨z ⟩ = 2.5. Contrary to what is generally believed, the distribution extends beyond 1022 cm-2 with a moderate slope of index ≈−3.5. This result matches the opacity-corrected distribution observed at z = 0 surprisingly well. The cosmological mass density of neutral gas in DLAs is found to be , evolving only mildly over the past 12 billion years.
377 citations
••
Institut d'Astrophysique de Paris1, University of Paris2, University of Wyoming3, University of La Laguna4, Spanish National Research Council5, University of Washington6, University of Utah7, New York University8, Apache Corporation9, Pennsylvania State University10, Max Planck Society11, Pierre-and-Marie-Curie University12, Harvard University13, Keele University14, École Polytechnique Fédérale de Lausanne15, Space Telescope Science Institute16, University of Arizona17, Institute of Cosmology and Gravitation, University of Portsmouth18, Ohio State University19, Sejong University20, Ohio University21, University of St Andrews22, Chinese Academy of Sciences23
TL;DR: The data release 14 quasar catalog (DR14Q) from the extended Baryon Oscillation Spectroscopic Survey (eBOSS) of the Sloan Digital Sky Survey IV (SDSS-IV) is presented in this article.
Abstract: We present the data release 14 Quasar catalog (DR14Q) from the extended Baryon Oscillation Spectroscopic Survey (eBOSS) of the Sloan Digital Sky Survey IV (SDSS-IV). This catalog includes all SDSS-IV/eBOSS objects that were spectroscopically targeted as quasar candidates and that are confirmed as quasars via a new automated procedure combined with a partial visual inspection of spectra, have luminosities (in a Λ CDM cosmology with H 0 = 70 km s−1 Mpc−1 , Ω M =0.3, and Ω Λ = 0.7), and either display at least one emission line with a full width at half maximum larger than 500 km s−1 or, if not, have interesting/complex absorption features. The catalog also includes previously spectroscopically-confirmed quasars from SDSS-I, II, and III. The catalog contains 526 356 quasars (144 046 are new discoveries since the beginning of SDSS-IV) detected over 9376 deg2 (2044 deg2 having new spectroscopic data available) with robust identification and redshift measured by a combination of principal component eigenspectra. The catalog is estimated to have about 0.5% contamination. Redshifts are provided for the Mg II emission line. The catalog identifies 21 877 broad absorption line quasars and lists their characteristics. For each object, the catalog presents five-band (u , g , r , i , z ) CCD-based photometry with typical accuracy of 0.03 mag. The catalog also contains X-ray, ultraviolet, near-infrared, and radio emission properties of the quasars, when available, from other large-area surveys. The calibrated digital spectra, covering the wavelength region 3610–10 140 Å at a spectral resolution in the range 1300 < 2500, can be retrieved from the SDSS Science Archiver Server.
366 citations
••
TL;DR: In this article, the authors study new consistent scalar-tensor theories of gravity with potentially interesting cosmological applications and derive the conditions for the existence of a primary constraint that prevents the propagation of an additional dangerous mode associated with higher order equations of motion.
Abstract: We study new consistent scalar-tensor theories of gravity recently introduced by Langlois and Noui with potentially interesting cosmological applications. We derive the conditions for the existence of a primary constraint that prevents the propagation of an additional dangerous mode associated with higher order equations of motion. We then classify the most general, consistent scalar-tensor theories that are at most quadratic in the second derivatives of the scalar field. In addition, we investigate the possible connection between these theories and (beyond) Horndeski through conformal and disformal transformations. Finally, we point out that these theories can be associated with new operators in the effective field theory of dark energy, which might open up new possibilities to test dark energy models in future surveys.
357 citations
••
Princeton University1, Lawrence Berkeley National Laboratory2, International Centre for Theoretical Physics3, New York University4, Apache Corporation5, University of Arizona6, University of Washington7, University of Sussex8, Institute of Cosmology and Gravitation, University of Portsmouth9, Pennsylvania State University10, Massachusetts Institute of Technology11
TL;DR: The 3D real-space clustering power spectrum of a sample of ∼600 000 luminous red galaxies measured by the Sloan Digital Sky Survey, using photometric redshifts, is presented in this paper.
Abstract: We present the 3D real-space clustering power spectrum of a sample of ∼600 000 luminous red galaxies measured by the Sloan Digital Sky Survey, using photometric redshifts. These galaxies are old, elliptical systems with strong 4000-A breaks, and have accurate photometric redshifts with an average error of Δz= 0.03. This sample of galaxies ranges from redshift z= 0.2 to 0.6 over 3528 deg2 of the sky, probing a volume of 1.5 h−3 Gpc3, making it the largest volume ever used for galaxy clustering measurements. We measure the angular clustering power spectrum in eight redshift slices and use well-calibrated redshift distributions to combine these into a high-precision 3D real-space power spectrum from k= 0.005 to k= 1 h Mpc−1. We detect power on gigaparsec scales, beyond the turnover in the matter power spectrum, at a ∼2σ significance for k < 0.01 h Mpc−1, increasing to 5.5σ for k < 0.02 h Mpc−1. This detection of power is on scales significantly larger than those accessible to current spectroscopic redshift surveys. We also find evidence for baryonic oscillations, both in the power spectrum, as well as in fits to the baryon density, at a 2.5 σ confidence level. The large volume and resulting small statistical errors on the power spectrum allow us to constrain both the amplitude and the scale dependence of the galaxy bias in cosmological fits. The statistical power of these data to constrain cosmology is ∼1.7 times better than previous clustering analyses. Varying the matter density and baryon fraction, we find ΩM= 0.30 ± 0.03, and Ωb/ΩM= 0.18 ± 0.04, for a fixed Hubble constant of 70 km s−1 Mpc−1 and a scale-invariant spectrum of initial perturbations. The detection of baryonic oscillations also allows us to measure the comoving distance to z= 0.5; we find a best-fitting distance of 1.73 ± 0.12 Gpc, corresponding to a 6.5 per cent error on the distance. These results demonstrate the ability to make precise clustering measurements with photometric surveys.
354 citations
Authors
Showing all 297 results
Name | H-index | Papers | Citations |
---|---|---|---|
Robert C. Nichol | 187 | 851 | 162994 |
Daniel Thomas | 134 | 846 | 84224 |
Will J. Percival | 129 | 473 | 87752 |
Tommaso Treu | 126 | 715 | 49090 |
Claudia Maraston | 103 | 362 | 59178 |
Marco Cavaglia | 93 | 372 | 60157 |
Ashley J. Ross | 90 | 248 | 46395 |
David A. Wake | 89 | 214 | 46124 |
László Á. Gergely | 89 | 426 | 60674 |
L. K. Nuttall | 89 | 253 | 54834 |
Rita Tojeiro | 87 | 229 | 43140 |
Roy Maartens | 86 | 432 | 23747 |
David Keitel | 85 | 253 | 56849 |
Davide Pietrobon | 83 | 152 | 62010 |
Gong-Bo Zhao | 81 | 287 | 35540 |