Search Publications
XMM-Newton surveys of the Canada-France Redshift Survey Fields - III. The environments of X-ray selected active galactic nuclei at 0.4 < z < 0.6
Lilly, S.; McCracken, H. J.; Eales, S. A. +3 more
The environmental properties of a sample of 31 hard X-ray selected active galactic nuclei (AGN) are investigated, from scales of 500 kpc down to 30 kpc, and are compared to a control sample of inactive galaxies. All the AGN lie in the redshift range 0.4 < z < 0.6. The accretion luminosity density of the Universe peaks close to this redshift …
Correlation patterns between 11 diffuse interstellar bands and ultraviolet extinction
Krełowski, J.; Megier, A.; Weselak, T.
We relate the equivalent widths of 11 diffuse interstellar bands, measured in the spectra of 49 stars, to different colour excesses in the ultraviolet. We find that most of the observed bands correlate positively with the extinction in the neighbourhood of the 2175-Åbump. Correlation with colour excesses in other parts of the extinction curve is m…
Outflowing material in the compact steep-spectrum source quasar 3C 48: evidence of jet-cloud interaction?
Saikia, D. J.; Srianand, R.; Gupta, Neeraj
We report on the detection of a zabs= 0.3654 associated absorption-line system in the ultraviolet spectrum of the compact steep-spectrum source (CSS) quasar 3C 48. The absorbing material is blueshifted with respect to the quasar emission-line redshift, zem= 0.3700, suggesting an outflow velocity of ~1000 km s-1. We…
Properties of FIRBACK-ELAIS 175-µm sources in the ELAIS N2 region
Dole, H.; Lagache, G.; Puget, J. -L. +15 more
We report on a search for the optical counterparts of 175-µm selected sources from the Far-Infrared Background (FIRBACK) survey in the European Large Area ISO Survey (ELAIS) N2 field. Applying a likelihood ratio technique to optical catalogues from the Isaac Newton Telescope - Wide Field Survey (INT-WFS), we found optical identifications for…
Discovery of absorption features of the accretion disc corona and systematic acceleration of the X-ray burst rate in XB1323-619
Church, M. J.; Reed, D.; Dotani, T. +2 more
We present results from analysis of the observation of the dipping, quasi-periodic bursting low mass X-ray binary XB1323-619 made with XMM-Newton in 2003 January. In spectral analysis of the non-dip, non-burst EPIC PN spectrum, a number of absorption lines were discovered, notably at 6.70 and 6.98 keV, which we identify with scattering by high ion…
The European Large Area ISO Survey: optical identifications of 15-µm and 1.4-GHz sources in N1 and N2
Vaccari, M.; Serjeant, S.; Rowan-Robinson, M. +9 more
We present the multiwavelength properties and catalogue of the 15µm and 1.4GHz radio sources detected in the European Large Area ISO Survey (ELAIS) areas N1 and N2. Using the optical data from the Wide Field Survey we use a likelihood ratio method to search for the counterparts of the 1056 and 691 sources detected at 15µm and 1.4GHz, r…
The influence of gravitational lensing on the spectra of lensed quasi-stellar objects
Popović, L. Č.; Chartas, G.
We consider the influence of (milli/micro)lensing on the spectra of lensed quasi-stellar objects (QSOs). We propose a method for the observational detection of microlensing in the spectra of lensed QSOs and apply it to the spectra of three lensed QSOs (PG 1115+080, Q1413+117 and Q0957+561) observed with the Hubble Space Telescope. We find that the…
The X-ray source population of the globular cluster M15: Chandra high-resolution imaging
Charles, P. A.; Davies, M. B.; Naylor, T. +5 more
The globular cluster M15 was observed on three occasions with the High Resolution Camera on-board Chandra in 2001 in order to investigate the X-ray source population in the cluster centre. After subtraction of the two bright central sources, four faint sources were identified within 50 arcsec of the core. One of these sources is probably the plane…
Heavy element abundances in DAO white dwarfs measured from FUSE data
Barstow, M. A.; Holberg, J. B.; Hubeny, I. +3 more
We present heavy element abundance measurements for 16 DAO white dwarfs, determined from Far-Ultraviolet Spectroscopic Explorer (FUSE) spectra. Evidence of absorption by heavy elements was found in the spectra of all the objects. Measurements were made using models that adopted the temperatures, gravities and helium abundances determined from both…
The dynamics of velocity fluctuations in the solar wind - I. Coronal mass ejections
Raga, A. C.; Lara, A.; de Gouveia Dal Pino, E. M. +3 more
In this paper we present a simple, analytic model for the dynamical evolution of supersonic velocity fluctuations at the base of the ambient solar wind. These fluctuations result in the formation of dense working surfaces that travel down the wind. It is shown how the initial parameters of the fluctuations (velocity, density and duration) are rela…