Search Publications
The WiggleZ Dark Energy Survey: survey design and first data release
Glazebrook, Karl; Pimbblet, Kevin A.; Drinkwater, Michael J. +24 more
The WiggleZ Dark Energy Survey is a survey of 240000 emission-line galaxies in the distant Universe, measured with the AAOmega spectrograph on the 3.9-m Anglo-Australian Telescope (AAT). The primary aim of the survey is to precisely measure the scale of baryon acoustic oscillations (BAO) imprinted on the spatial distribution of these galaxies at l…
The dependence of Type Ia Supernovae luminosities on their host galaxies
Sullivan, M.; Lidman, C.; Astier, P. +22 more
Precision cosmology with Type Ia supernovae (SNe Ia) makes use of the fact that SN Ia luminosities depend on their light-curve shapes and colours. Using Supernova Legacy Survey (SNLS) and other data, we show that there is an additional dependence on the global characteristics of their host galaxies: events of the same light-curve shape and colour …
The ACS Survey of Galactic Globular Clusters. IX. Horizontal Branch Morphology and the Second Parameter Phenomenon
Anderson, Jay; Dotter, Aaron; Sarajedini, Ata +11 more
The horizontal branch (HB) morphology of globular clusters (GCs) is most strongly influenced by metallicity. The second parameter phenomenon, first described in the 1960s, acknowledges that metallicity alone is not enough to describe the HB morphology of all GCs. In particular, astronomers noticed that the outer Galactic halo contains GCs with red…
Dissecting the Gravitational lens B1608+656. II. Precision Measurements of the Hubble Constant, Spatial Curvature, and the Dark Energy Equation of State
Treu, T.; Blandford, R. D.; Auger, M. W. +5 more
Strong gravitational lens systems with measured time delays between the multiple images provide a method for measuring the "time-delay distance" to the lens, and thus the Hubble constant. We present a Bayesian analysis of the strong gravitational lens system B1608+656, incorporating (1) new, deep Hubble Space Telescope (HST) observations, (2) a ne…
Three Dimensional Anisotropic k Spectra of Turbulence at Subproton Scales in the Solar Wind
Belmont, G.; Sahraoui, F.; Rezeau, L. +2 more
We show the first three dimensional (3D) dispersion relations and k spectra of magnetic turbulence in the solar wind at subproton scales. We used the Cluster data with short separations and applied the k-filtering technique to the frequency range where the transition to subproton scales occurs. We show that the cascade is carried by highly oblique…
Physics of Solar Prominences: I—Spectral Diagnostics and Non-LTE Modelling
Heinzel, P.; Vial, J. -C.; Parenti, S. +5 more
This review paper outlines background information and covers recent advances made via the analysis of spectra and images of prominence plasma and the increased sophistication of non-LTE ( i.e. when there is a departure from Local Thermodynamic Equilibrium) radiative transfer models. We first describe the spectral inversion techniques that have bee…
The Detection of a Population of Submillimeter-Bright, Strongly Lensed Galaxies
Smail, I.; Rodighiero, G.; Valtchanov, I. +86 more
Gravitational lensing is a powerful astrophysical and cosmological probe and is particularly valuable at submillimeter wavelengths for the study of the statistical and individual properties of dusty star-forming galaxies. However, the identification of gravitational lenses is often time-intensive, involving the sifting of large volumes of imaging …
The Effect of a Strong Stellar Flare on the Atmospheric Chemistry of an Earth-like Planet Orbiting an M Dwarf
Walkowicz, Lucianne M.; Segura, Antígona; Hawley, Suzanne +2 more
Main sequence M stars pose an interesting problem for astrobiology: their abundance in our galaxy makes them likely targets in the hunt for habitable planets, but their strong chromospheric activity produces high-energy radiation and charged particles that may be detrimental to life. We studied the impact of the 1985 April 12 flare from the M dwar…
The Initial Mass Function of Early-Type Galaxies
Treu, Tommaso; Gavazzi, Raphaël; Marshall, Philip J. +3 more
We determine an absolute calibration of the initial mass function (IMF) of early-type galaxies, by studying a sample of 56 gravitational lenses identified by the Sloan Lenses ACS Survey. Under the assumption of standard Navarro, Frenk, and White dark matter halos, a combination of lensing, dynamical, and stellar population synthesis models is used…
The X-ray to optical-UV luminosity ratio of X-ray selected type 1 AGN in XMM-COSMOS
Le Floc'h, E.; Jahnke, K.; Salvato, M. +29 more
We present a study of the X-ray to optical properties of a sample of 545 X-ray selected type 1 AGN, from the XMM-COSMOS survey, over a wide range of redshifts (0.04 < z < 4.25) and X-ray luminosities (40.6 ≤ Log L[2-10]~keV ≤ 45.3). About 60% of them are spectroscopically identified type 1 AGN, while the others have a reliable pho…