Search Publications
X-ray spectroscopy of the Virgo Cluster out to the virial radius
Böhringer, H.; Simionescu, A.; Allen, S. W. +2 more
We present results from the analysis of a mosaic of 13 XMM-Newton pointings covering the Virgo Cluster from its centre northwards out to a radius r∼ 1.2 Mpc (∼4?5), reaching the virial radius and beyond. This is the first time that the properties of a modestly sized (Mvir∼ 1.4 × 1014 M⊙, kT∼ 2.3 keV), dynamically y…
Random forest automated supervised classification of Hipparcos periodic variable stars
Rimoldini, L.; Mowlavi, N.; Nienartowicz, K. +14 more
We present an evaluation of the performance of an automated classification of the Hipparcos periodic variable stars into 26 types. The sub-sample with the most reliable variability types available in the literature is used to train supervised algorithms to characterize the type dependencies on a number of attributes. The most useful attributes eva…
2XMM ultraluminous X-ray source candidates in nearby galaxies
Roberts, T. P.; Mateos, S.; Walton, D. J. +1 more
Ultraluminous X-ray sources (ULXs) are some of the most enigmatic X-ray bright sources known to date. It is generally accepted that they cannot host black holes as large as those associated with active galaxies, but they appear to be significantly more luminous than their better understood Galactic X-ray binary (XRB) cousins, while displaying an i…
Strong-lensing analysis of a complete sample of 12 MACS clusters at z > 0.5: mass models and Einstein radii
Broadhurst, Tom; Zitrin, Adi; Benítez, Narciso +2 more
We present the results of a strong-lensing analysis of a complete sample of 12 very luminous X-ray clusters at z > 0.5 using HST/ACS images. Our modelling technique has uncovered some of the largest known critical curves outlined by many accurately predicted sets of multiple images. The distribution of Einstein radii has a median value of ≃28 a…
Herschel-ATLAS: counterparts from the ultraviolet-near-infrared in the science demonstration phase catalogue
Rodighiero, G.; Ivison, R. J.; Sutherland, W. +45 more
We present a technique to identify optical counterparts of 250-µm-selected sources from the Herschel-ATLAS survey. Of the 6621 250 µm > 32-mJy sources in our science demonstration catalogue we find that ∼60 per cent have counterparts brighter than r = 22.4 mag in the Sloan Digital Sky Survey. Applying a likelihood ratio technique we…
Herschel-ATLAS: first data release of the Science Demonstration Phase source catalogues
Rodighiero, G.; Ivison, R. J.; Clements, D. L. +28 more
The Herschel Astrophysical Terahertz Large Area Survey (Herschel-ATLAS) is a survey of 550 deg2 with the Herschel Space Observatory in five far-infrared and submillimetre bands. The first data for the survey, observations of a field 4 × 4 deg2 in size, were taken during the Science Demonstration Phase (SDP), and reach a 5σ no…
A wide Chandra view of the core of the Perseus cluster
Churazov, E.; Young, A. J.; Fabian, A. C. +12 more
We present new Chandra images of the X-ray emission from the core of the Perseus cluster of galaxies. The total observation time is now 1.4 Ms. New depressions in X-ray surface brightness are discovered to the north of NGC 1275, which we interpret as old rising bubbles. They imply that bubbles are long-lived and do not readily breakup when rising …
X-ray absorption by broad-line region clouds in Mrk 766
Maiolino, R.; Elvis, M.; Fabbiano, G. +5 more
We present a new analysis of a 9-d long XMM-Newton monitoring of the narrow-line Seyfert 1 galaxy Mrk 766. We show that the strong changes in the spectral shape, which occurred during this observation, can be interpreted as due to broad-line region clouds crossing the line of sight to the X-ray source. Within the occultation scenario, the spectral…
The ultraviolet properties of star-forming galaxies - I. HST WFC3 observations of very high redshift galaxies
Wilkins, Stephen M.; Bunker, Andrew J.; Caruana, Joseph +2 more
The acquisition of deep near-IR imaging with Wide Field Camera 3 on the Hubble Space Telescope has provided the opportunity to study the very high redshift Universe. For galaxies up to z≈ 7.7 sufficient wavelength coverage exists to probe the rest-frame ultraviolet (UV) continuum without contamination from either Lyman α emission or the Lyman α br…
The optical morphologies of the 2 Jy sample of radio galaxies: evidence for galaxy interactions
Morganti, R.; Tadhunter, C. N.; Ramos Almeida, C. +3 more
We present deep Gemini Multi-Object Spectrograph South (GMOS-S)/Gemini optical broad-band images for a complete sample of 46 southern 2 Jy radio galaxies at intermediate redshifts (0.05 < z < 0.7). Based on them, we discuss the role of galaxy interactions in the triggering of powerful radio galaxies (PRGs). The high-quality observations pres…