Search Publications
The ultraluminous state revisited: fractional variability and spectral shape as diagnostics of super-Eddington accretion
Middleton, Matthew J.; Sutton, Andrew D.; Roberts, Timothy P.
Although we are nearing a consensus that most ultraluminous X-ray sources (ULXs) below 1041 erg s-1 represent stellar mass black holes accreting in a super-Eddington `ultraluminous' accretion state, little is yet established of the physics of this extreme accretion mode. Here, we use a combined X-ray spectral and timing analy…
The Suzaku view of highly ionized outflows in AGN - I. Statistical detection and global absorber properties
Reeves, James N.; Tombesi, Francesco; Miller, Lance +4 more
We present the results of a new spectroscopic study of Fe K-band absorption in active galactic nuclei (AGN). Using data obtained from the Suzaku public archive we have performed a statistically driven blind search for Fe XXV Heα and/or Fe XXVI Lyα absorption lines in a large sample of 51 Type 1.0-1.9 AGN. Through extensive Monte Carlo simulations …
The sizes, masses and specific star formation rates of massive galaxies at 1.3 < z < 1.5: strong evidence in favour of evolution via minor mergers
McLure, R. J.; Dunlop, J. S.; Jarvis, M. J. +12 more
We report the results of a comprehensive study of the relationship between galaxy size, stellar mass and specific star formation rate (sSFR) at redshifts 1.3 < z < 1.5. Based on a mass-complete (M⋆ ≥ 6 × 1010 M⊙), spectroscopic sample from the UK Infrared Deep Sky Survey (UKIDSS) Ultradeep Survey, with accura…
The UV continua and inferred stellar populations of galaxies at z ≃ 7-9 revealed by the Hubble Ultra-Deep Field 2012 campaign
Bowler, R. A. A.; McLure, R. J.; Dunlop, J. S. +16 more
We use the new ultra-deep, near-infrared imaging of the Hubble Ultra-Deep Field (HUDF) provided by our UDF12 Hubble Space Telescope (HST) Wide Field Camera 3/IR campaign to explore the rest-frame ultraviolet (UV) properties of galaxies at redshifts z > 6.5. We present the first unbiased measurement of the average UV power-law index, <β>, …
A statistical relation between the X-ray spectral index and Eddington ratio of active galactic nuclei in deep surveys
Sanders, D. B.; Taniguchi, Y.; Alexander, D. M. +33 more
We present an investigation into how well the properties of the accretion flow on to a supermassive black hole may be coupled to those of the overlying hot corona. To do so, we specifically measure the characteristic spectral index, Γ, of a power-law energy distribution, over an energy range of 2-10 keV, for X-ray selected, broad-lined radio-quiet…
Origins of weak lensing systematics, and requirements on future instrumentation (or knowledge of instrumentation)
Cropper, Mark; Schrabback, Tim; Hoekstra, Henk +11 more
The first half of this paper explores the origin of systematic biases in the measurement of weak gravitational lensing. Compared to previous work, we expand the investigation of point spread function instability and fold in for the first time the effects of non-idealities in electronic imaging detectors and imperfect galaxy shape measurement algor…
The SLUGGS Survey: kinematics for over 2500 globular clusters in 12 early-type galaxies
Spitler, Lee R.; Forbes, Duncan A.; Romanowsky, Aaron J. +10 more
We present a spectrophotometric survey of 2522 extragalactic globular clusters (GCs) around 12 early-type galaxies, nine of which have not been published previously. Combining space-based and multicolour wide-field ground-based imaging, with spectra from the Keck/DEep Imaging Multi-Object Spectrograph (DEIMOS) instrument, we obtain an average of 1…
Characterization of SCUBA-2 450 µm and 850 µm selected galaxies in the COSMOS field
Casey, Caitlin M.; Koss, Michael; Capak, Peter +8 more
We present deep 450 µm and 850 µm observations of a large, uniformly covered 394 arcmin2 area in the Cosmic Evolution Survey (COSMOS) field obtained with the SCUBA-2 instrument on the James Clerk Maxwell Telescope (JCMT). We achieve root-mean-square noise values of σ450 = 4.13 mJy and σ850 = 0.80 mJy. T…
Early-type galaxies have been the predominant morphological class for massive galaxies since only z ∼ 1
Conselice, Christopher J.; Trujillo, Ignacio; Häußler, Boris +1 more
Present-day massive galaxies are composed mostly of early-type objects. It is unknown whether this was also the case at higher redshifts. In a hierarchical assembling scenario the morphological content of the massive population is expected to change with time from disc-like objects in the early Universe to spheroid-like galaxies at present. In thi…
An HST optical-to-near-IR transmission spectrum of the hot Jupiter WASP-19b: detection of atmospheric water and likely absence of TiO
Aigrain, S.; Pont, F.; Fortney, J. J. +14 more
We measure the transmission spectrum of WASP-19b from three transits using low-resolution optical spectroscopy from the Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph (STIS). The STIS spectra cover a wavelength range of 0.29-1.03 µm, with resolving power R = 500. The optical data are combined with archival near-infrared da…