Apparent Brightness » Statistics http://apparentbrightness.net astronomy and stuff Mon, 03 Dec 2007 16:07:54 +0000 http://wordpress.org/?v=2.6.1 en Monolithic or hierarchical star formation? A new statistical analysis http://apparentbrightness.net/2007/12/03/monolithic-or-hierarchical-star-formation-a-new-statistical-analysis/ http://apparentbrightness.net/2007/12/03/monolithic-or-hierarchical-star-formation-a-new-statistical-analysis/#comments Mon, 03 Dec 2007 15:35:59 +0000 Thomas Marquart http://apparentbrightness.net/2007/12/03/monolithic-or-hierarchical-star-formation-a-new-statistical-analysis/
  • Kampakoglou et al.
  • http://arxiv.org/abs/0709.1104
  • Statistical model to predict/fit the star formation history of the universe. Hierarchical formation through merging seems to be favoured but not enough to exclude the monolithic scenario. Outflow models and dust are critical.

    • My impression is that the two priciple modes of galaxy formation seem to be subject to fashion among astronomers. While monolithic has been favoured in the early days of extragalacitc astronomy, the hierarchical formation was preferred until lately when it was realised that the former probably also plays a role.

    ]]>     http://apparentbrightness.net/2007/12/03/monolithic-or-hierarchical-star-formation-a-new-statistical-analysis/feed/     The Initial Cluster Mass Function of Super Star Clusters in Irregular and Spiral Galaxies http://apparentbrightness.net/2007/11/02/the-initial-cluster-mass-function-of-super-star-clusters-in-irregular-and-spiral-galaxies/ http://apparentbrightness.net/2007/11/02/the-initial-cluster-mass-function-of-super-star-clusters-in-irregular-and-spiral-galaxies/#comments Fri, 02 Nov 2007 09:30:35 +0000 Thomas Marquart http://apparentbrightness.net/2007/11/02/the-initial-cluster-mass-function-of-super-star-clusters-in-irregular-and-spiral-galaxies/
  • Dowell et al.
  • http://arxiv.org/abs/astro-ph/0611586
  • SSCs in nearby spirals and irregulars from SDSS
  • SDSS colors plus spectral evolutionary modelling to determine cluster ages and mass.
  • They find a steeper slope for the mass function (at high masses) in irregulars as compared to spirals.
  • I wonder how reliable the masses are from this method. It’s a tricky business and dynamical cluster masses would be nicer.
    • ]]>     http://apparentbrightness.net/2007/11/02/the-initial-cluster-mass-function-of-super-star-clusters-in-irregular-and-spiral-galaxies/feed/     Scaling Relations of Dwarf Galaxies without Supernova-Driven Winds http://apparentbrightness.net/2007/10/31/scaling-relations-of-dwarf-galaxies-without-supernova-driven-winds/ http://apparentbrightness.net/2007/10/31/scaling-relations-of-dwarf-galaxies-without-supernova-driven-winds/#comments Wed, 31 Oct 2007 13:18:27 +0000 Thomas Marquart http://apparentbrightness.net/2007/10/31/scaling-relations-of-dwarf-galaxies-without-supernova-driven-winds/
  • Tassis et al.
  • http://arxiv.org/abs/astro-ph/0609763
  • Dwarf galaxies: correlations between their global stellar and dynamical properties, such as circular velocity, mass-to-light ratio, stellar mass, surface brightness, and metallicity.
  • low and high z
  • simulation work
  • SN winds vs. ineficient SF
  • useful to compare to where our data fall on these correlations
    • ]]>     http://apparentbrightness.net/2007/10/31/scaling-relations-of-dwarf-galaxies-without-supernova-driven-winds/feed/