Search Publications
The clustering of the SDSS DR7 main Galaxy sample - I. A 4 per cent distance measure at z = 0.15
Howlett, Cullan; Manera, Marc; Ross, Ashley J. +3 more
We create a sample of spectroscopically identified galaxies with z < 0.2 from the Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7), covering 6813 deg2. Galaxies are chosen to sample the highest mass haloes, with an effective bias of 1.5, allowing us to construct 1000 mock galaxy catalogues (described in Paper II), which we use to…
The Canadian Cluster Comparison Project: detailed study of systematics and updated weak lensing masses
Muzzin, Adam; Hoekstra, Henk; Babul, Arif +4 more
Masses of clusters of galaxies from weak gravitational lensing analyses of ever larger samples are increasingly used as the reference to which baryonic scaling relations are compared. In this paper we revisit the analysis of a sample of 50 clusters studied as part of the Canadian Cluster Comparison Project. We examine the key sources of systematic…
Weighing the giants - IV. Cosmology and neutrino mass
Kelly, Patrick L.; Allen, Steven W.; Ebeling, Harald +14 more
We employ robust weak gravitational lensing measurements to improve cosmological constraints from measurements of the galaxy cluster mass function and its evolution, using X-ray selected clusters detected in the ROSAT All-Sky Survey. Our lensing analysis constrains the absolute mass scale of such clusters at the 8 per cent level, including both st…
Filament identification through mathematical morphology
Koch, Eric W.; Rosolowsky, Erik W.
We present a new algorithm for detecting filamentary structure FILFINDER. The algorithm uses the techniques of mathematical morphology for filament identification, presenting a complementary approach to current algorithms which use matched filtering or critical manifolds. Unlike other methods, FILFINDER identifies filaments over a wide dynamic ran…
Cosmic discordance: are Planck CMB and CFHTLenS weak lensing measurements out of tune?
Jain, Bhuvnesh; Zuntz, Joe; Bridle, Sarah +2 more
We examine the level of agreement between low-redshift weak lensing data and the cosmic microwave background using measurements from the Canada-France-Hawaii Telescope Lensing Survey (CFHTLenS) and Planck+Wilkinson Microwave Anisotropy Probe (WMAP) polarization. We perform an independent analysis of the CFHTLenS six bin tomography results of Heyma…
Accounting for baryonic effects in cosmic shear tomography: determining a minimal set of nuisance parameters using PCA
Gnedin, Nickolay Y.; Eifler, Tim; Hearin, Andrew P. +3 more
Systematic uncertainties that have been subdominant in past large-scale structure (LSS) surveys are likely to exceed statistical uncertainties of current and future LSS data sets, potentially limiting the extraction of cosmological information. Here we present a general framework (Principal Component Analysis - PCA - marginalization) to consistent…
Large-scale alignments from WMAP and Planck
Schwarz, Dominik J.; Starkman, Glenn D.; Copi, Craig J. +1 more
We revisit the alignments of the largest structures observed in the cosmic microwave background (CMB) using the seven and nine-year Wilkinson Microwave Anisotropy Probe (WMAP) and first-year Planck data releases. The observed alignments - the quadrupole with the octopole and their joint alignment with the direction of our motion with respect to th…
redMaPPer - III. A detailed comparison of the Planck 2013 and SDSS DR8 redMaPPer cluster catalogues
Rykoff, E. S.; Rozo, E.; Melin, Jean-Baptiste +1 more
We compare the Planck Sunyaev-Zeldovich (SZ) cluster sample (PSZ1) to the Sloan Digital Sky Survey (SDSS) redMaPPer catalogue, finding that all Planck clusters within the redMaPPer mask and within the redshift range probed by redMaPPer are contained in the redMaPPer cluster catalogue. These common clusters define a tight scaling relation in the ri…
Calibrating the cosmic distance scale ladder: the role of the sound-horizon scale and the local expansion rate as distance anchors
Verde, Licia; Riess, Adam; Jimenez, Raul +1 more
We exploit cosmological model-independent measurements of the expansion history of the Universe to provide a cosmic distance ladder. These are supernovae Type Ia used as standard candles (at redshift between 0.01 and 1.3) and baryon acoustic oscillations (at redshifts between 0.1 and 0.8) as standard rulers. We calibrate (anchor) the ladder in two…
Effect of primordial magnetic fields on the ionization history
Finelli, F.; Paoletti, D.; Rubiño-Martín, J. A. +1 more
Primordial magnetic fields (PMF) damp at scales smaller than the photon diffusion and free-streaming scale. This leads to heating of ordinary matter (electrons and baryons), which affects both the thermal and ionization history of our Universe. Here, we study the effect of heating due to ambipolar diffusion and decaying magnetic turbulence. We fin…