Search Publications
Scaling relations for galaxy clusters in the Millennium-XXL simulation
White, S. D. M.; Baugh, C. M.; Frenk, C. S. +3 more
We present a very large high-resolution cosmological N-body simulation, the Millennium-XXL or MXXL, which uses 303 billion particles to represent the formation of dark matter structures throughout a 4.1 Gpc box in a Λ cold dark matter cosmology. We create sky maps and identify large samples of galaxy clusters using surrogates for four different ob…
A simplified view of blazars: clearing the fog around long-standing selection effects
D'Elia, V.; Polenta, G.; Giommi, P. +3 more
We propose a scenario where blazars are classified into flat-spectrum radio quasars (FSRQs), BL Lacertae (BL Lac) objects, low-synchrotron, or high-synchrotron peaked objects according to a varying mix of the Doppler-boosted radiation from the jet, the emission from the accretion disc, the broad-line region, and the light from the host galaxy. In …
The Canadian Cluster Comparison Project: weak lensing masses and SZ scaling relations
Hoekstra, Henk; Babul, Arif; Mahdavi, Andisheh +1 more
The Canadian Cluster Comparison Project is a comprehensive multi-wavelength survey targeting 50 massive X-ray selected clusters of galaxies to examine baryonic tracers of cluster mass and to probe the cluster-to-cluster variation in the thermal properties of the hot intra-cluster medium. In this paper we present the weak lensing masses, based on t…
Improved models for cosmic infrared background anisotropies: new constraints on the infrared galaxy population
Knox, Lloyd; Oh, S. Peng; Shang, Cien +1 more
The power spectrum of cosmic infrared background (CIB) anisotropies is sensitive to the connection between star formation and dark matter haloes over the entire cosmic star formation history. Here we develop a model that associates star-forming galaxies with dark matter haloes and their subhaloes. The model is based on a parametrized relation betw…
Sunyaev-Zel'dovich clusters in Millennium gas simulations
Thomas, Peter A.; Kay, Scott T.; Liddle, Andrew R. +5 more
Large surveys using the Sunyaev-Zel'dovich (SZ) effect to find clusters of galaxies are now starting to yield large numbers of systems out to high redshift, many of which are new discoveries. In order to provide theoretical interpretation for the release of the full SZ cluster samples over the next few years, we have exploited the large-volume Mil…
Optical flux and spectral variability of blazars
Gupta, Alok C.; Wiita, Paul J.; Bachev, R. +9 more
We report the results of optical monitoring for a sample of 11 blazars including 10 BL Lacertae objects (BL Lacs) and one flat spectrum radio quasar (FSRQ). We have measured the multiband optical flux and colour variations in these blazars on intraday and short-term time-scales of months and have limited data for two more blazars. These photometri…
A Sunyaev-Zel'dovich take on cluster radio haloes - I. Global scaling and bi-modality using Planck data
Basu, Kaustuv
Giant radio haloes in galaxy clusters are the primary evidence for the existence of relativistic particles (cosmic rays) and magnetic fields over Mpc scales. Observational tests for the different theoretical models explaining their powering mechanism have so far been obtained through X-ray selection of clusters, e.g. by comparing cluster X-ray lum…
The dust energy balance in the edge-on spiral galaxy NGC 4565
Gordon, Karl D.; De Looze, Ilse; Baes, Maarten +20 more
We combine new dust continuum observations of the edge-on spiral galaxy NGC 4565 in all Herschel/Spectral and Photometric Imaging Receiver (250, 350 and 500 µm) wavebands, obtained as part of the Herschel Reference Survey, and a large set of ancillary data (Spitzer, Sloan Digital Sky Survey, Galaxy Evolution Explorer) to analyse its dust ene…
Galaxy cluster outskirts: a universal entropy profile for relaxed clusters?
Fabian, A. C.; Sanders, J. S.; Walker, S. A. +1 more
We fit a functional form for a universal intracluster medium entropy profile to the scaled entropy profiles of a catalogue of X-ray galaxy cluster outskirts results, which are all relaxed cool core clusters at redshift below 0.25. We also investigate the functional form suggested by Lapi et al. and Cavaliere et al. for the behaviour of the entropy…
Clustering of submillimetre galaxies in a self-regulated baryon collapse model
Danese, L.; Negrello, M.; Lapi, A. +3 more
We investigate anisotropies in the cosmic infrared background (CIB) using a combination of the physical evolutionary model for proto-spheroid galaxies of Granato et al. and an independent halo occupation distribution analysis. After having re-calibrated the cumulative flux function dS/dz at ?m using the available determinations of the shot-noise a…