Browsing by Author "Baes, Maarten"

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    G2C2-IV.A novel approach to study the radial distributions of multiple populations in Galactic globular clusters
    (OXFORD UNIV PRESS, 2015) Vanderbeke, Joachim; De Propris, Roberto; De Rijcke, Sven; Baes, Maarten; West, Michael; Alonso Garcia, Javier; Kunder, Andrea
    We use the horizontal branch (HB) morphology of 48 Galactic globular clusters (GCs) to study the radial distributions of the different stellar populations known to exist in GCs. Assuming that the (extremely) blue HB stars correspond to stars enriched in helium and light elements, we compare the radial distributions of stars selected according to colour on the HB to trace the distribution of the secondary stellar populations in GCs. Unlike other cases, our data show that the populations are well mixed in 80 per cent of the cases studied. This provides some constraints on the mechanisms proposed to pollute the interstellar medium in young GCs.
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    Optical colours and spectral indices of z=0.1 EAGLE galaxies with the 3D dust radiative transfer code SKIRT
    (2017) Trayford, James W.; Camps, Peter; Theuns, Tom; Baes, Maarten; Bower, Richard G.; Crain, Robert A.; Gunawardhana, Madusha L. P.; Schaller, Matthieu; Schaye, Joop; Frenk, Carlos S.
    We present mock optical images, broad-band and H alpha fluxes, and D4000 spectral indices for 30 145 galaxies from the EAGLE hydrodynamical simulation at redshift z = 0.1, modelling dust with the SKIRT Monte Carlo radiative transfer code. The modelling includes a subgrid prescription for dusty star-forming regions, with both the subgrid obscuration of these regions and the fraction of metals in diffuse interstellar dust calibrated against far-infrared fluxes of local galaxies. The predicted optical colours as a function of stellar mass agree well with observation, with the SKIRT model showing marked improvement over a simple dust-screen model. The orientation dependence of attenuation is weaker than observed because EAGLE galaxies are generally puffier than real galaxies, due to the pressure floor imposed on the interstellar medium (ISM). The mock Ha luminosity function agrees reasonably well with the data, and we quantify the extent to which dust obscuration affects observed H alpha fluxes. The distribution of D4000 break values is bimodal, as observed. In the simulation, 20 per cent of galaxies deemed 'passive' for the SKIRT model, i.e. exhibiting D4000 > 1.8, are classified 'active' when ISM dust attenuation is not included. The fraction of galaxies with stellar mass greater than 10(10) M-circle dot that are deemed passive is slightly smaller than observed, which is due to low levels of residual star formation in these simulated galaxies. Colour images, fluxes and spectra of EAGLE galaxies are to be made available through the public EAGLE data base.
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    The dust covering factor in active galactic nuclei
    (2016) Stalevski, Marko; Ricci, Claudio; Ueda, Yoshihiro; Lira, Paulina; Fritz, Jacopo; Baes, Maarten