Search Publications
Galaxy Zoo: an independent look at the evolution of the bar fraction over the last eight billion years from HST-COSMOS
Schawinski, Kevin; Bamford, Steven P.; Nichol, Robert C. +11 more
We measure the redshift evolution of the bar fraction in a sample of 2380 visually selected disc galaxies found in Cosmic Evolution Survey (COSMOS) Hubble Space Telescope (HST) images. The visual classifications used both to identify the disc sample and to indicate the presence of stellar bars were provided by citizen scientists via the Galaxy Zoo…
Cosmological constraints from the double source plane lens SDSSJ0946+1006
Auger, Matthew W.; Collett, Thomas E.
We present constraints on the equation of state of dark energy, w, and the total matter density, ΩM, derived from the double-source-plane strong lens SDSSJ0946+1006, the first cosmological measurement with a galaxy-scale double-source-plane lens. By modelling the primary lens with an elliptical power-law mass distribution, and including…
Teasing bits of information out of the CMB energy spectrum
Jeong, Donghui; Chluba, Jens
Departures of the cosmic microwave background (CMB) frequency spectrum from a blackbody - commonly referred to as spectral distortions - encode information about the thermal history of the early Universe (redshift z ≲ few × 106). While the signal is usually characterized as µ- and y-type distortion, a smaller residual (non-y/non-&…
A multiwavelength consensus on the main sequence of star-forming galaxies at z ∼ 2
Berta, S.; Magnelli, B.; Lutz, D. +18 more
We compare various star formation rate (SFR) indicators for star-forming galaxies at 1.4 < z < 2.5 in the COSMOS field. The main focus is on the SFRs from the far-IR (PACS-Herschel data) with those from the ultraviolet, for galaxies selected according to the BzK criterion. FIR-selected samples lead to a vastly different slope of the SFR-stel…
General relativistic modelling of the negative reverberation X-ray time delays in AGN
Papadakis, I. E.; Emmanoulopoulos, D.; Dovčiak, M. +1 more
We present the first systematic physical modelling of the time-lag spectra between the soft (0.3-1 keV) and the hard (1.5-4 keV) X-ray energy bands, as a function of Fourier frequency, in a sample of 12 active galactic nuclei which have been observed by XMM-Newton. We concentrate particularly on the negative X-ray time-lags (typically seen above 1…
Improved mass and radius constraints for quiescent neutron stars in ω Cen and NGC 6397
Campana, S.; Heinke, C. O.; Cohn, H. N. +8 more
We use Chandra and XMM-Newton observations of the globular clusters ω Cen and NGC 6397 to measure the spectrum of their quiescent neutron stars (NSs), and thus to constrain the allowed ranges of mass and radius for each. We also use Hubble Space Telescope photometry of NGC 6397 to identify a potential optical companion to the quiescent NS, and fin…
The stellar and dark matter distributions in elliptical galaxies from the ensemble of strong gravitational lenses
Oguri, Masamune; Falco, Emilio E.; Rusu, Cristian E.
We derive the average mass profile of elliptical galaxies from the ensemble of 161 strong gravitational lens systems selected from several surveys, assuming that the mass profile scales with the stellar mass and effective radius of each lensing galaxy. The total mass profile is well fitted by a power law ρ(r) ∝ rγ with best-fitting slop…
HerMES: dust attenuation and star formation activity in ultraviolet-selected samples from z∼ 4 to ∼ 1.5
Ilbert, O.; Béthermin, M.; Buat, V. +16 more
We study the link between observed ultraviolet (UV) luminosity, stellar mass and dust attenuation within rest-frame UV-selected samples at z ∼ 4, ∼ 3 and ∼1.5. We measure by stacking at 250, 350 and 500 µm in the Herschel/Spectral and Photometric Imaging Receiver images from the Herschel Multi-Tiered Extragalactic Survey (HerMES) program the…
The spin temperature of high-redshift damped Lyman α systems
Momjian, E.; Ryan-Weber, E. V.; de Bruyn, A. G. +10 more
We report results from a programme aimed at investigating the temperature of neutral gas in high-redshift damped Lyman α absorbers (DLAs). This involved (1) H I 21 cm absorption studies of a large sample of DLAs towards radio-loud quasars, (2) very long baseline interferometric studies to measure the low-frequency quasar core fractions, and (3) op…
The HST/ACS Coma Cluster Survey - X. Nuclear star clusters in low-mass early-type galaxies: scaling relations
Ferguson, Henry C.; Balcells, Marc; Graham, Alister W. +16 more
We present scaling relations between structural properties of nuclear star clusters and their host galaxies for a sample of early-type dwarf galaxies observed as part of the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) Coma Cluster Survey. We have analysed the light profiles of 200 early-type dwarf galaxies in the magnitude range…