• Mon, NOV 17, 2014
    SPEAKER: Gary Mamon (Institut d'Astrophysique de Paris)
    TITLE: Compact groups of galaxies: their nature, properties and assembly history
    ABSTRACT: Compact groups of galaxies are selected to be nearby, isolated, very dense systems of 4 or more galaxies in a range of 3 magnitudes. Their high densities and low velocity dispersions make them the ideal sites for galaxy interactions and mergers, and the present-day massive galaxies may have assembled within compact groups. Yet, half the galaxies in the popular, visually selected, Hickson catalog are spiral, with no statistical signs of galaxy mergers or luminosity segregation. This has led to a debate on whether compact group samples are strongly contaminated by chance alignments of galaxies along the line of sight. I will address the nature of compact groups through the use of mock compact group catalogues extracted from the outputs of semi-analytical models of galaxy formation, themselves run on the halo merger trees of the Millennium cosmological simulations. The use of such mock compact groups allows the quantification of the fraction of compact groups that are chance projections in comparison to those that are physically dense in 3D. The mock compact groups are roughly 10 times more frequent than observed, suggesting a strong incompleteness of the Hickson catalog. I will present the properties of a new, complete, sample of compact groups, extracted from 2MASS in a similar, but automatic fashion as the Hickson catalog. I will highlight the strong differences between the 2MASS-selected compacts groups and the Hickson sample and ask whether star forming galaxies have normal specific star formation rates, are bursty, or anemic. Finally, I will study the mass assembly of compact groups, using the semi-analytical models to compare different possible formation channels.
    contact: Andrea Biviano
  • Wed, NOV 26, 2014
    SPEAKER: Umberto Maio (OATS)
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    contact: Umberto Maio
  • Wed, Dec 3, 2014
    SPEAKER: Claudia Cicone (Cavendish Laboratory, University of Cambridge, UK)
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    contact: Stefano Cristiani
  • Wed, Dec 10, 2014
    SPEAKER: Klaus Dolag (Universitäs Sternwarte, Muenchen, DE)
    TITLE: The Magneticum Pathfinder Simulations
    ABSTRACT:Upcoming astronomical surveys and instruments like Planck, SPT, PanStars,DES, Euclid, LOFAR, eRosita and many more will need a theoretical counterpart in form of simulations which follow the formation of cosmological structures in so far unaccomplished detail, taking into account enough physical processes to allow a self consistent comparison to observations at multiple wavelength and throughout the entire epoch of structure formation. I will report on preliminary results from a recent simulation campaign, where we followed the formation of cosmological structures in so far unaccomplished detail, performing a large set of cosmological, hydrodynamical simulations covering up to Gpc^3 volumes, taking into account enough physical processes (star- formation, chemical enrichment, AGN feedback) to allow a self consistent comparison to observations at multiple wavelength.
    contact: Stefano Borgani
  • Wed, DEC 17, 2014
    SPEAKER: Michele Fumagalli (Durham Univ., UK)
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    contact: Valentina D'Odorico
  • Wed, JAN 7, 2015
    SPEAKER: Gabriele Cescutti (AIP Potsdam, DE)
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    contact: Francesca Matteucci
  • Wed, JAN 21, 2015
    SPEAKER: Benedetta Ciardi (MPA Garching, DE)
    TITLE:
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    contact: Valentina D'Odorico
  • Wed, FEB 25, 2015 (TBC)
    SPEAKER: Roland Diehl (MPE, Garching, DE)
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    contact: John Danziger
  • Wed, APR 29, 2015
    SPEAKER:Hans Ludwig (Zentrum für Astronomie, University of Heidelberg, DE)
    TITLE:
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    contact: Paolo Molaro
  • Wed, MAY 6, 2015
    SPEAKER:Piercarlo Bonifacio (GEPI, Observatoire de Paris, Meudon, FR)
    TITLE:
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    contact: Paolo Molaro
  • Wed, MAY 27, 2015 (TBC)
    SPEAKER: Martha Haynes (Cornell University, NY, USA)
    TITLE:
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    contact: Stefano Borgani
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