Now showing items 21-40 of 613

    • 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 ...
    • Starburst galaxies and structure in the submillimetre background towards the Hubble Deep Field 

      Peacock, John A.; Rowan-Robinson, Michael; Blain, Andrew W.; James S. Dunlop, James; Efstathiou, Andreas; Hughes, David Handel; Jenness, Tim; Ivison, Robert J.; Andy R. Lawrence, Andy; Longair, Malcolm S.; Robert Mann, Robert; Oliver, Sebastian James; Serjeant, Stephen B.G. (2000-10-21)
      We use an 850-μm SCUBA map of the Hubble Deep Field (HDF) to study the dust properties of optically-selected starburst galaxies at high redshift. The optical/infrared (IR) data in the HDF allow a photometric redshift to ...
    • The ISOPHOT 170μm serendipity survey: I. Compact sources with galaxy associations 

      Stickel, Manfred; Lemke, Dietrich; Klaas, Ulrich; Beichman, Charles A.; Rowan-Robinson, Michael; Efstathiou, Andreas; Bogun, Stefan; Kessler, Martin F.; Richter, Gotthard M. (2000-12-01)
      The first set of compact sources observed in the ISOPHOT 170 μm Serendipity Survey is presented. From the slew data with low (I100μm ≤ 15 MJy/sr) cirrus background, 115 well-observed sources with a high signal-to-noise ...
    • The European large area ISO survey - III. 90-μm extragalactic source counts 

      Efstathiou, Andreas; Oliver, Sebastian James; Rowan-Robinson, Michael; Surace, Christian; Sumner, Timothy J.; Héraudeau, Ph; Linden-Vørnle, M. J.D.; Rigopoulou, Dimitra; Serjeant, Stephen B.G.; Robert Mann, Robert; 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. (2000-12-21)
      We present results and source counts at 90 μm extracted from the preliminary analysis of the European Large Area ISO Survey (ELAIS). The survey covered about 12 deg2 of the sky in four main areas and was carried out with ...
    • Investigating the use of genetic programming for a classic one-machine scheduling problem 

      Dimopoulos, Christos; Zalzala, Ali M.S. (2001-01-01)
      Genetic programming has rarely been applied to manufacturing optimisation problems. In this paper the potential use of genetic programming for the solution of the one-machine total tardiness problem is investigated. Genetic ...
    • Mid infrared polarisation of ultraluminous infrared galaxies 

      Siebenmorgen, Ralf; Efstathiou, Andreas (2001-01-01)
      The mid infrared polarisation properties of four Ultraluminous Infrared Galaxies (ULIRGs) have been investigated by broad band filter observations with the ISOCAM instrument on board the Infrared Space Observatory (ISO). ...
    • The extended counterpart of submm source Lockman 850.1 

      Lutz, Dieter; James S. Dunlop, James; Almaini, Omar; Andreani, Paola M.; Blain, Andrew W.; Efstathiou, Andreas; Fox, Matt J.; Genzel, Reinhardt; Hasinger, Guenther H.; Hughes, David Handel; Ivison, Robert J.; Andy R. Lawrence, Andy; Robert Mann, Robert; Oliver, Sebastian James; Peacock, John A.; Rigopoulou, Dimitra; Rowan-Robinson, Michael; Scott, Susan E.; Serjeant, Stephen B.G.; Tacconi, Linda J. (2001-01-01)
      The IRAM Plateau de Bure mm interferometer and deep K-band imaging have been used to identify the brightest submm source detected in the Lockman field of the UK 8 mJy SCUBA survey. The near infrared counterpart is an ...
    • On the average Cartier-Foata height of traces 

      Krob, Daniel; Mairesse, Jean; Michos, Ioannis C. (2001-01-01)
      The height of a trace is the height of the corresponding heap of pieces in X.G. Viennot's formalism, or equivalently the number of components in its Cartier-Foata decomposition. Let h(t) and |t| be, respectively, the height ...
    • A hierarchical clustering methodology based on genetic programming for the solution of simple cell-formation problems 

      Dimopoulos, Christos; Mort, Neil (2001-01-10)
      The problem of identifying machine cells and corresponding part families in cellular manufacturing has been extensively researched over the last thirty years. However, the complexity of the problem and the considerable ...
    • The nonstellar infrared continuum of seyfert galaxies 

      Alonso-Herrero, Almudena; Quillen, Alice C.; Simpson, Chris J.; Efstathiou, Andreas; Ward, Martin J. (2001-03-01)
      JHKL'M (1-5 μm) imaging of a sample of Seyfert 2 galaxies is presented. We have performed an accurate estimate of the near-infrared nonstellar nuclear fluxes. We confirm that the near-infrared nuclear continuum between 1 ...
    • The European Large Area ISO Survey - IV. The preliminary 90-μm luminosity function 

      Serjeant, Stephen B.G.; Efstathiou, Andreas; Oliver, Sebastian James; Surace, Christian; Héraudeau, Ph; Linden-Vørnle, M. J.D.; Gruppioni, Carlotta; La Franca, Fabio; Rigopoulou, Dimitra; Morel, Thierry; Crockett, Hans; Sumner, Timothy J.; Rowan-Robinson, Michael; Graham, Matthew J. (2001-04-01)
      We present the luminosity function of 90-μm-selected galaxies from the European Large Area ISO Survey (ELAIS), extending to z = 0.3. Their luminosities are in the range 109 < h-265L/L⊙ < 1012, i.e. non-ultraluminous. From ...
    • The European large-area infrared space observatory survey V: A beppoSAX hard X-ray survey of the S1 region 

      Alexander, David M.; La Franca, Fabio; Fiore, Fabrizio; Barcons, X.; Ciliegi, Paolo; Danese, Luigi; Della Ceca, Roberto; Franceschini, Alberto; Gruppioni, Carlotta; Matt, Giorgio; Matute, Israel; Oliver, Sebastian James; Pompilio, Fulvio; Wolter, Anna; Efstathiou, Andreas; Héraudeau, Ph; Perola, Giuseppe Cesare; Perri, Matteo; Rigopoulou, Dimitra; Rowan-Robinson, Michael; Serjeant, Stephen B.G. (2001-06-10)
      We present BeppoSAX observations of the southern S1 region in the European Large-Area Infrared Space Observatory (ISO) Survey (ELAIS). These observations cover an area of ∼1.7 deg2 and reach an on-axis (∼0.7 deg2) 2-10 keV ...
    • Starburst activity in a ROSAT narrow emission-line galaxy 

      Gunn, Katherine F.; McHardy, Ian M.M.; Almaini, Omar; Shanks, Tom; Sumner, Timothy J.; Muxlow, Thomas W.B.; Efstathiou, Andreas; Jones, Laurence R.; Croom, Scott M.; Manners, James C.; Newsam, Andrew M.; Mason, Keith O.; Serjeant, Stephen B.G.; Rowan-Robinson, Michael (2001-06-21)
      We present multiwaveband photometric and optical spectropolarimetric observations of the R = 15.9 narrow emission-line galaxy R117_A which lies on the edge of the error circle of the ROSAT X-ray source R117. The overall ...
    • Constraints on the nuclear emission of the Circinus galaxy: The torus 

      Ruiz, Milagros; Efstathiou, Andreas; Alexander, David M.; James H. Hough, James (2001-08-11)
      In the context of the unified model of Seyfert galaxies, we use observations from the literature and a radiative transfer model to investigate the near-IR to mm emission produced by the presumed torus in the Circinus galaxy, ...