Search Publications
Stellar clusters in M83: formation, evolution, disruption and the influence of the environment
Bastian, N.; Larsen, S. S.; Smith, L. J. +6 more
We study the stellar cluster population in two adjacent fields in the nearby, face-on spiral galaxy M83 using multiwavelength Wide Field Camera 3/Hubble Space Telescope imaging. After automatic detection procedures, the clusters are selected through visual inspection to be centrally concentrated, symmetric, and resolved on the images, which allows…
Investigations of dust heating in M81, M83 and NGC 2403 with the Herschel Space Observatory
Clements, D. L.; Roussel, H.; Cooray, A. +21 more
We use Spitzer Space Telescope and Herschel Space Observatory far-infrared data along with ground-based optical and near-infrared data to understand how dust heating in the nearby face-on spiral galaxies M81, M83 and NGC 2403 is affected by the starlight from all stars and by the radiation from star-forming regions. We find that 70/160 ?m surface …
Extreme AGN feedback in the MAssive Cluster Survey: a detailed study of X-ray cavities at z>0.3
Fabian, A. C.; Hlavacek-Larrondo, J.; Edge, A. C. +4 more
We present the first statistical study of X-ray cavities in distant clusters of galaxies (z > 0.3). With the aim of providing further insight into how active galactic nucleus (AGN) feedback operates at higher redshift, we have analysed the Chandra X-ray observations of the MAssive Cluster Survey (MACS) and searched for surface brightness depres…
Herschel-ATLAS: multi-wavelength SEDs and physical properties of 250 µm selected galaxies at z < 0.5
Ivison, R. J.; Clements, D. L.; Scott, D. +38 more
We present a pan-chromatic analysis of an unprecedented sample of 1402 250 µm selected galaxies at z < 0.5 (z¯=0.24) from the Herschel-ATLAS survey. We complement our Herschel 100-500 µm data with UV-K-band photometry from the Galaxy And Mass Assembly (GAMA) survey and apply the MAGPHYS energy-balance technique to produce pan-chroma…
Discovery of radio haloes and double relics in distant MACS galaxy clusters: clues to the efficiency of particle acceleration
Vazza, F.; Edge, A. C.; Bonafede, A. +6 more
We have performed 323 MHz observations with the Giant Metrewave Radio Telescope of the most promising candidates selected from the MACS catalogue. The aim of the work is to extend our knowledge of the radio halo and relic populations to z > 0.3, the epoch in which massive clusters are formed. In MACSJ1149.5+2223 and MACSJ1752.1+4440, we discove…
A combined optical and X-ray study of unobscured type 1 active galactic nuclei - III. Broad-band SED properties
Done, Chris; Ward, Martin; Jin, Chichuan
In this third paper in a series of three, we present a detailed study of the broad-band spectral energy distribution (SED) of active galactic nuclei (AGNs) based on a nearby unobscured type 1 AGN sample. We perform a systematic cross-correlation study of several key parameters, i.e. Γ2-10 keV, L2-10 keV, Lbol/L
Temperature-pressure profile of the hot Jupiter HD 189733b from HST sodium observations: detection of upper atmospheric heating
Pont, F.; Lecavelier des Etangs, A.; Vidal-Madjar, A. +4 more
We present transmission spectra of the hot Jupiter HD 189733b taken with the Space Telescope Imaging Spectrograph (STIS) aboard Hubble Space Telescope (HST). The spectra cover the wavelength range 5808-6380 Å with a resolving power of R= 5000. We detect absorption from the Na I doublet within the exoplanet's atmosphere at the 9σ confidence level w…
The Galaxy Zoo survey for giant AGN-ionized clouds: past and present black hole accretion events
Schawinski, Kevin; Sonnenfeld, Alessandro; Keel, William C. +8 more
Some active galactic nuclei (AGN) are surrounded by extended emission-line regions (EELRs), which trace both the illumination pattern of escaping radiation and its history over the light travel time from the AGN to the gas. From a new set of such EELRs, we present evidence that the AGN in many Seyfert galaxies undergo luminous episodes 0.2-2 ? yea…
Heavily obscured quasar host galaxies at z ∼ 2 are discs, not major mergers
Schawinski, Kevin; Urry, C. Megan; Simmons, Brooke D. +2 more
We explore the nature of heavily obscured quasar host galaxies at z∼ 2 using deep Hubble Space Telescope Wide Field Camera 3/infrared imaging of 28 dust-obscured galaxies (DOGs) to investigate the role of major mergers in driving black hole growth. The high levels of obscuration of the quasars selected for this study act as a natural coronagraph, …
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…