Now showing items 1-20 of 151

    • Polarimetry and modelling of narrow-line active galaxies 

      Young, Stuart; James H. Hough, James; Efstathiou, Andreas; Wills, Beverley J.; Bailey, Jeremy A.; Ward, Martin J.; Axon, David J. (1996-01-01)
      We present optical spectropolarimetry along with optical and infrared broad-band filter polarimetry of selected warm [f(25 μm)/f(60 μm) ≥ 0.3] IRAS galaxies and other known Seyfert 2 galaxies. Broad lines in polarized flux ...
    • Scattered broad optical lines in the polarized flux spectrum of the FR II galaxy 3C 321 

      Young, Stuart; James H. Hough, James; Efstathiou, Andreas; Wills, Beverley J.; Axon, David J.; Bailey, Jeremy A.; Ward, Martin J. (1996-01-01)
      We present optical/infrared broad-band filter polarimetry and optical spectropolarimetry of the powerful FR II galaxy 3C 321. The latter observations reveal a scattered broad component to the Hα emission line, detectable ...
    • The nuclear torus in the active galaxy NGC 1068 

      Young, Stuart; Packham, Christopher C.; James H. Hough, James; Efstathiou, Andreas (1996-01-01)
      We present near-infrared polarized images of the active galaxy NGC 1068. At these wavelengths, the counter-cone is observed in scattered light. At H (1.64 μm) we detect an absorption band across the counter-cone, which we ...
    • Dusty discs in AGN 

      Efstathiou, Andreas (1996-01-01)
      A modified version of the code of Efstathiou and Rowan-Robinson (1990), that solves accurately the axially symmetric radiative transfer problem in dust clouds, is used to model the infrared emission from dust in Active ...
    • Polarimetry and the torus 

      James H. Hough, James; Young, Stuart; Efstathiou, Andreas (1996-01-01)
      While the torus plays an obvious role in blocking direct light, and thus increasing the observed polarization from scattering, its role in directly producing polarized flux is less clear. Contributions to the infrared ...
    • Observations of the Hubble Deep Field with the Infrared Space Observatory - II. Source detection and photometry 

      Goldschmidt, Pippa; Oliver, Sebastian James; Serjeant, Stephen B.G.; Baker, Amanda C.; Eaton, Nick; Efstathiou, Andreas; Gruppioni, Carlotta; Robert Mann, Robert; Mobasher, Bahram; Rowan-Robinson, Michael; Sumner, Timothy J.; Danese, Luigi; Elbaz, David; Franceschini, Alberto; Egami, Eiichi; Kontizas, Maria; Andy R. Lawrence, Andy; McMahon, R. G.; Nørgaard-Nielsen, Hans Ulrik; Pérez-Fournón, Ismaël; González-Serrano, José Ignacio (1997-01-01)
      We present positions and fluxes of point sources found in the Infrared Space Observatory (ISO) images of the Hubble Deep Field (HDF) at 6.7 and 15 μm. We have constructed algorithmically selected 'complete' flux-limited ...
    • Observations of the Hubble Deep Field with the Infrared Space Observatory - IV. Association of sources with Hubble Deep Field galaxies 

      Robert Mann, Robert; Oliver, Sebastian James; Serjeant, Stephen B.G.; Rowan-Robinson, Michael; Baker, Amanda C.; Eaton, Nick; Efstathiou, Andreas; Goldschmidt, Pippa; Mobasher, Bahram; Sumner, Timothy J.; Danese, Luigi; Elbaz, David; Franceschini, Alberto; Egami, Eiichi; Kontizas, Maria; Andy R. Lawrence, Andy; McMahon, R. G.; Nørgaard-Nielsen, Hans Ulrik; Pérez-Fournón, Ismaël; González-Serrano, José Ignacio (1997-01-01)
      We discuss the identification of sources detected by the Infrared Space Observatory (ISO) at 6.7 and 15 μm in the Hubble Deep Field (HDF) region. We conservatively associate ISO sources with objects in existing optical and ...
    • Observations of the Hubble Deep Field with the Infrared Space Observatory - I. Data reduction, maps and sky coverage 

      Serjeant, Stephen B.G.; Eaton, Nick; Oliver, Sebastian James; Efstathiou, Andreas; Goldschmidt, Pippa; Robert Mann, Robert; Mobasher, Bahram; Rowan-Robinson, Michael; Sumner, Timothy J.; Danese, Luigi; Elbaz, David; Franceschini, Alberto; Egami, Eiichi; Kontizas, Maria; Andy R. Lawrence, Andy; McMahon, R. G.; Nørgaard-Nielsen, Hans Ulrik; Pérez-Fournón, Ismaël; González-Serrano, José Ignacio (1997-01-01)
      We present deep imaging at 6.7 and 15 μm from the CAM instrument on the Infrared Space Observatory (ISO), centred on the Hubble Deep Field (HDF). These are the deepest integrations published to date at these wavelengths ...
    • Polarization due to dichroic absorption and emission by aligned grains in dusty discs 

      Efstathiou, Andreas; McCall, Alan; James H. Hough, James (1997-01-01)
      We present a method for calculating the infrared polarization due to absorption and emission by aligned grains distributed in a disc or a torus. The temperature distribution in the torus is calculated with the axially ...
    • Observations of the Hubble Deep Field with the Infrared Space Observatory - V. Spectral energy distributions, starburst models and star formation history 

      Rowan-Robinson, Michael; Robert Mann, Robert; Oliver, Sebastian James; Efstathiou, Andreas; Eaton, Nick; Goldschmidt, Pippa; Mobasher, Bahram; Serjeant, Stephen B.G.; Sumner, Timothy J.; Danese, Luigi; Elbaz, David; Franceschini, Alberto; Egami, Eiichi; Kontizas, Maria; Andy R. Lawrence, Andy; McMahon, R. G.; Nørgaard-Nielsen, Hans Ulrik; Pérez-Fournón, Ismaël; González-Serrano, José Ignacio (1997-01-01)
      We have modelled the spectral energy distributions of the 13 Hubble Deep Field (HDF) galaxies reliably detected by the Infrared Space Observatoiy (ISO). For two galaxies the emission detected by ISO is consistent with being ...
    • Observations of the Hubble Deep Field with the Infrared Space Observatory - III. Source counts and P(D) analysis 

      Oliver, Sebastian James; Goldschmidt, Pippa; Franceschini, Alberto; Serjeant, Stephen B.G.; Efstathiou, Andreas; Verma, Aprajita; Gruppioni, Carlotta; Eaton, Nick; Robert Mann, Robert; Mobasher, Bahram; Pearson, Chris P.; Rowan-Robinson, Michael; Sumner, Timothy J.; Danese, Luigi; Elbaz, David; Egami, Eiichi; Kontizas, Maria; Andy R. Lawrence, Andy; McMahon, R. G.; Nørgaard-Nielsen, Hans Ulrik; Pérez-Fournón, Ismaël; González-Serrano, José Ignacio (1997-01-01)
      We present source counts at 6.7 and 15 μm from our maps of the Hubble Deep Field (HDF) region, reaching 38.6 μJy at 6.7 μm and 255 μJy at 15 μm. These are the first ever extragalactic number counts to be presented at 6.7 ...
    • High-redshift star formation in the Hubble Deep Field revealed by a submillimetre-wavelength survey 

      Hughes, David Handel; Serjeant, Stephen B.G.; James S. Dunlop, James; Rowan-Robinson, Michael; Blain, Andrew W.; Robert Mann, Robert; Ivison, Robert J.; Peacock, John A.; Efstathiou, Andreas; Gear, Walter K.P.; Oliver, Sebastian James; Andy R. Lawrence, Andy; Longair, Malcolm S.; Goldschmidt, Pippa; Jenness, Tim (1998-07-16)
      In the local Universe, most galaxies are dominated by stars, with less than ten per cent of their visible mass in the form of gas. Determining when most of these stars formed is one of the central issues of observational ...
    • The ISOPHOT far-infrared serendipity north ecliptic pole minisurvey 

      Stickel, Manfred; Bogun, Stefan; Lemke, Dietrich; Klaas, Ulrich; Toth, L. Viktor; Herbstmeier, Uwe; Richter, Gotthard M.; Assendorp, Rob; Laureijs, René J.; Kessler, Martin F.; Burgdorf, Martin J.; Beichman, Charles A.; Rowan-Robinson, Michael; Efstathiou, Andreas (1998-08-01)
      The ISOPHOT Serendipity Survey fills the otherwise unused slew time between ISO's fine pointings with measurements in an unexplored wavelength regime near 200 μm. In order to test point source extraction software, the ...
    • Random and deterministic perturbation of a class of skew-product systems 

      Broomhead, David S.; Hadjiloucas, Demetris; Nicol, Matthew J. (1999-01-01)
      This paper is concerned with the stability properties of skew-products T (x, y) = (f(x), g(x, y)) in which (f, X, μ) is an ergodic map of a compact metric space X and g: X x ℝn → ℝn is continuous. We assume that the ...
    • Observations and a model for the infrared continuum of Centaurus A 

      Alexander, David M.; Efstathiou, Andreas; James H. Hough, James; Aitken, David K.; Lutz, Dieter; Roche, Patrick F.; Sturm, Eckhard (1999-11-21)
      We present ISOSWS, ISOPHOT_S and 8-13 μm observations of Centaurus A which show prominent PAH and silicate features. These and other data are used to construct a model for the infrared continuum. We find that, in a small ...
    • Random and deterministic perturbation of a class of skew-product systems 

      Broomhead, David S.; Hadjiloucas, Demetris; Nicol, Matthew J. (1999-12-01)
      This paper is concerned with the stability properties of skew-products T (x, y) = (f(x), g(x, y)) in which (f, X, μ) is an ergodic map of a compact metric space X and g: X x ℝn → ℝn is continuous. We assume that the ...
    • Massive star formation in galaxies: Radiative transfer models of the UV to millimetre emission of starburst galaxies 

      Efstathiou, Andreas; Rowan-Robinson, Michael; Siebenmorgen, Ralf (2000-04-21)
      We present illustrative models for the UV to millimetre emission of starburst galaxies which are treated as an ensemble of optically thick giant molecular clouds (GMCs) centrally illuminated by recently formed stars. The ...
    • Recent developments in evolutionary computation for manufacturing optimization: Problems, solutions, and comparisons 

      Dimopoulos, Christos (2000-07-01)
      The use of intelligent techniques in the manufacturing field has been growing the last decades due to the fact that most manufacturing optimization problems are combinatorial and NP hard. This paper examines recent ...
    • The European Large Area ISO Survey - I. Goals, definition and observations 

      Oliver, Sebastian James; Rowan-Robinson, Michael; Alexander, David M.; Almaini, Omar; Balcells, Marc; Baker, Amanda C.; Barcons, X.; Barden, Marco; Bellas-Velidis, Ioannis; Cabrera-Guerra, F.; Carballo, Ruth; Césarsky, Catherine J.; Ciliegi, Paolo; Clements, David L.; Crockett, Hans; Danese, Luigi; Dapergolas, Anastasios; Drolias, B.; Eaton, Nick; Efstathiou, Andreas; Egami, Eiichi; Elbaz, David; Fadda, Dario T.; Fox, Matt J.; Franceschini, Alberto; Genzel, Reinhardt; Goldschmidt, Pippa; Graham, Matthew J.; González-Serrano, José Ignacio; González-Solares, Eduardo A.; Granato, Gianluigi; Gruppioni, Carlotta; Herbstmeier, Uwe; Héraudeau, Ph; Joshi, M. K. (2000-08-21)
    • The European Large Area ISO Survey - II. Mid-infrared extragalactic source counts 

      Serjeant, Stephen B.G.; Oliver, Sebastian James; Rowan-Robinson, Michael; Crockett, Hans; Missoulis, Vasilis; Sumner, Timothy J.; Gruppioni, Carlotta; Robert Mann, Robert; Eaton, Nick; Elbaz, David; Clements, David L.; Baker, Amanda C.; Efstathiou, Andreas; Césarsky, Catherine J.; Danese, Luigi; Franceschini, Alberto; Genzel, Reinhardt; Andy R. Lawrence, Andy; Lemke, Dietrich; McMahon, R. G.; Miley, George K.; Puget, Jean Loup; Rocca-Volmerange, Brigitte M. (2000-08-21)
      We present preliminary source counts at 6.7 and 15 μm from the preliminary analysis of the European Large Area ISO Survey, with limiting flux densities of ∼2mJy at 15 μm and ∼1 mJy at 6.7 μm. We separate the stellar ...