Search Publications
Discovery of a possibly old galaxy at z= 6.027, multiply imaged by the massive cluster Abell 383
Richard, Johan; Stark, Daniel P.; Kneib, Jean-Paul +3 more
We report the discovery of a unique z= 6.027 galaxy, multiply imaged by the cluster Abell 383 and detected in new Hubble Space Telescope ACS and WFC3 imaging, as well as in Warm Spitzer observations. This galaxy was selected as a pair of i-dropouts; its suspected high redshift was confirmed by the measurement of a strong Lyman α line in both image…
The near-infrared broad emission line region of active galactic nuclei - II. The 1-µm continuum
Elvis, Martin; Karovska, Margarita; Korista, Kirk T. +3 more
We use quasi-simultaneous near-infrared (near-IR) and optical spectroscopy from four observing runs to study the continuum around 1 µm in 23 well-known broad emission line active galactic nuclei (AGN). We show that, after correcting the optical spectra for host galaxy light, the AGN continuum around this wavelength can be approximated by the…
The SWELLS survey - II. Breaking the disc-halo degeneracy in the spiral galaxy gravitational lens SDSS J2141-0001
Treu, Tommaso; Marshall, Philip J.; Holden, Bradford P. +6 more
The degeneracy among the disc, bulge and halo contributions to galaxy rotation curves prevents an understanding of the distribution of baryons and dark matter in disc galaxies. In an attempt to break this degeneracy, we present an analysis of the strong gravitational lens SDSS J2141-0001, discovered as part of the Sloan Lens ACS survey. The lens g…
Understanding reverberation lags in 1H0707-495
Fabian, A. C.; Uttley, P.; Zoghbi, A.
The first reverberation lag from the vicinity of a supermassive black hole was recently detected in the NLS1 galaxy 1H0707-495. We interpreted the lag as due to reflection from matter close to the black hole, within a few gravitational radii of the event horizon (an inner reflector). It has since been claimed by Miller et al. that the lag can be p…
The shocking transit of WASP-12b: modelling the observed early ingress in the near-ultraviolet
Vidotto, A. A.; Fossati, L.; Helling, Ch. +4 more
Near-ultraviolet (near-UV) observations of WASP-12b have revealed an early ingress compared to the optical transit light curve. This has been interpreted as due to the presence of a magnetospheric bow shock which forms when the relative velocity of the planetary and stellar material is supersonic. We aim to reproduce this observed early ingress by…
Iron line profiles in Suzaku spectra of bare Seyfert galaxies
Porquet, D.; Reeves, J. N.; Terashima, Y. +3 more
We methodically model the broad-band Suzaku spectra of a small sample of six 'bare' Seyfert galaxies: Ark 120, Fairall 9, MCG -02-14-009, Mrk 335, NGC 7469 and SWIFT J2127.4+5654. The analysis of bare Seyferts allows a consistent and physical modelling of active galactic nuclei due to a weak amount of any intrinsic warm absorption, removing the de…
An XMM-Newton spectral survey of 12 µm selected galaxies - II. Implications for AGN selection and unification
Nandra, Kirpal; Brightman, Murray
We present a multi-waveband analysis of a 126-galaxy sub-sample of the 12 µm galaxy sample (12MGS), for which we have carried out a detailed X-ray spectral analysis in a previous paper. We determine the activity class of the galaxies by way of optical-line ratio diagnostics and characterize the optical classes by their X-ray, 12 µm and…
Physical conditions of the interstellar medium of high-redshift, strongly lensed submillimetre galaxies from the Herschel-ATLAS
Altieri, B.; Rodighiero, G.; Valtchanov, I. +51 more
We present Herschel-Spectral and Photometric Imaging Receiver (SPIRE) Fourier transform spectrometer (FTS) and radio follow-up observations of two Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS)-detected strongly lensed distant galaxies. In one of the targeted galaxies H-ATLAS J090311.6+003906 (SDP.81), we detect [O III] 88 µm a…
The ubiquity and dual nature of ultra-compact dwarfs
Kannappan, Sheila J.; Norris, Mark A.
We present the discovery of several ultra-compact dwarfs (UCDs) located in field/group environments. Examination of these objects, plus literature UCDs, confirms the existence of two distinct formation channels for these compact stellar systems. We find that the UCDs we have discovered around the group elliptical NGC 3923 (and most UCDs in general…
The XMM Cluster Survey: X-ray analysis methodology
Hilton, Matt; Stanford, S. A.; Stott, John P. +20 more
The XMM Cluster Survey (XCS) is a serendipitous search for galaxy clusters using all publicly available data in the XMM-Newton Science Archive. Its main aims are to measure cosmological parameters and trace the evolution of X-ray scaling relations. In this paper we describe the data processing methodology applied to the 5776 XMM observations used …