Apparent Brightness » SDSS http://apparentbrightness.net astronomy and stuff Mon, 03 Dec 2007 16:07:54 +0000 http://wordpress.org/?v=2.5.1 en 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/     The Galaxy Zoo http://apparentbrightness.net/2007/11/02/the-galaxy-zoo/ http://apparentbrightness.net/2007/11/02/the-galaxy-zoo/#comments Fri, 02 Nov 2007 07:53:12 +0000 Thomas Marquart http://apparentbrightness.net/2007/11/02/the-galaxy-zoo/ Things that happen when you neglect your blog #187: You find a finished article that you forgot to publish and which is quite outdated now. You now have to bite the bullet and publish it anyway, because you are to cheap to ditch it.

    “You” in that case is, of course, me. So here it comes:

    It has already been all over the news and blogs, but I cannot resist to comment a little more on the newly opened Galaxy Zoo.

    The site shows galaxy images from the SDSS to the public and lets them classify them. Categories are very simple: spirals (subdivided into direction of rotation and edge-on), ellipticals, mergers and stars/unknown. The aim is, of course, to use the human brains’ excellent capability to recognise pattern, even if they are feeble. What a wonderful project! I am quite sure it will become popular and therefore successful.

    As a “professional”, however, one gets into troubles when trying this myself. That’s because of a little too much background knowledge. Mainly, I find it hard to ignore the color of a galaxy or some other details that are visible. This probably biases my judgment more towards the “other” classification as compared to the more specific ones.

    ]]>     http://apparentbrightness.net/2007/11/02/the-galaxy-zoo/feed/     Observational evidence for AGN feedback in early-type galaxies http://apparentbrightness.net/2007/10/31/observational-evidence-for-agn-feedback-in-early-type-galaxies/ http://apparentbrightness.net/2007/10/31/observational-evidence-for-agn-feedback-in-early-type-galaxies/#comments Wed, 31 Oct 2007 13:40:36 +0000 Thomas Marquart http://apparentbrightness.net/2007/10/31/observational-evidence-for-agn-feedback-in-early-type-galaxies/
  • Schawinski et al.
  • http://arxiv.org/abs/0709.3015
  • Sloan study
  • morphologically select from “green valley”
  • star formation history
  • time sequence
  • quenching
    • ]]>     http://apparentbrightness.net/2007/10/31/observational-evidence-for-agn-feedback-in-early-type-galaxies/feed/