Search Publications
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…
Quasar outflows and AGN feedback in the extreme UV: HST/COS observations of HE 0238-1904
Arav, Nahum; Borguet, Benoit; Chamberlain, Carter +2 more
Spectroscopic observations of quasar outflows at rest-frame 500-1000 Å have immense diagnostic power. We present analyses of such data, where absorption troughs from O IV and O IV* allow us to obtain the distance of the outflows from the AGN and troughs from Ne VIII and Mg X reveal the warm absorber phase of the outflow. Their inferred column dens…
HST hot-Jupiter transmission spectral survey: evidence for aerosols and lack of TiO in the atmosphere of WASP-12b
Aigrain, S.; Pont, F.; Fortney, J. J. +17 more
We present Hubble Space Telescope (HST) optical transmission spectra of the transiting hot-Jupiter WASP-12b, taken with the Space Telescope Imaging Spectrograph instrument. The resulting spectra cover the range 2900-10 300 Å which we combined with archival Wide Field Camera 3 spectra and Spitzer photometry to cover the full optical to infrared wav…
The UV and X-ray activity of the M dwarfs within 10 pc of the Sun
Liefke, C.; Micela, G.; Marino, A. +2 more
M dwarfs are the most numerous stars in the Galaxy. They are characterized by strong magnetic activity. The ensuing high-energy emission is crucial for the evolution of their planets and the eventual presence of life on them. We systematically study the X-ray and ultraviolet emission of a subsample of M dwarfs from a recent proper-motion survey, s…
The redshift and mass dependence on the formation of the Hubble sequence at z > 1 from CANDELS/UDS
Grogin, Norman A.; Kocevski, Dale D.; Koekemoer, Anton M. +16 more
In this paper we present a detailed study of the structures and morphologies of a sample of 1188 massive galaxies with M* ≥ 1010 M⊙ between redshifts z = 1 and 3 within the Ultra Deep Survey (UDS) region of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) field. Using this sample we dete…