Search Publications
The prevalence of dust on the exoplanet HD 189733b from Hubble and Spitzer observations
Aigrain, S.; Pont, F.; Gibson, N. P. +3 more
The hot Jupiter HD 189733b is the most extensively observed exoplanet. Its atmosphere has been detected and characterized in transmission and eclipse spectroscopy, and its phase curve measured at several wavelengths. This paper brings together the results of our campaign to obtain the complete transmission spectrum of the atmosphere of this planet…
The death of massive stars - II. Observational constraints on the progenitors of Type Ibc supernovae
Fraser, Morgan; Smartt, Stephen J.; Eldridge, John J. +2 more
The progenitors of many Type II core-collapse supernovae (SNe) have now been identified directly on pre-discovery imaging. Here, we present an extensive search for the progenitors of Type Ibc SNe in all available pre-discovery imaging since 1998. There are 12 Type Ibc SNe with no detections of progenitors in either deep ground-based or Hubble Spac…
Suzaku observations of `bare' active galactic nuclei
Fabian, A. C.; Nardini, E.; Reis, R. C. +2 more
We present an X-ray spectral analysis of a large sample of 25 `bare' active galactic nuclei (AGN), sources with little or no complicating intrinsic absorption, observed with Suzaku. Our work focuses on studying the potential contribution from relativistic disc reflection and examining the implications of this interpretation for the intrinsic spect…
Discovery of a relation between black hole mass and soft X-ray time lags in active galactic nuclei
Cappi, M.; Ponti, G.; Fabian, A. C. +5 more
We carried out a systematic analysis of time lags between X-ray energy bands in a large sample (32 sources) of unabsorbed, radio quiet active galactic nuclei (AGN), observed by XMM-Newton. The analysis of X-ray lags (up to the highest/shortest frequencies/time-scales), is performed in the Fourier-frequency domain, between energy bands where the so…
TPZ: photometric redshift PDFs and ancillary information by using prediction trees and random forests
Brunner, Robert J.; Carrasco Kind, Matias
With the growth of large photometric surveys, accurately estimating photometric redshifts, preferably as a probability density function (PDF), and fully understanding the implicit systematic uncertainties in this process, has become increasingly important. In this paper, we present a new, publicly available, parallel, machine learning algorithm th…
Generating artificial light curves: revisited and updated
Papadakis, I. E.; Emmanoulopoulos, D.; McHardy, I. M.
The production of artificial light curves with known statistical and variability properties is of great importance in astrophysics. Consolidating the confidence levels during cross-correlation studies, understanding the artefacts induced by sampling irregularities, establishing detection limits for future observatories are just some of the applica…
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>, …