Daily paper summaries

The Top 12 of 2012

11. How to Mess With the Dark Matter in Dwarf Galaxies

Why it is important: The dark matter haloes that envelope all galaxies are predicted to have similar shapes: a ‘cuspy’ density profile that increases steeply at the center. Here, a new model is proposed to explain why the haloes of many dwarf galaxies instead have a ‘core’ profile with a relatively constant density in their central regions.

This paper presents simulations showing that underdense gas bubbles (above) are repeatedly formed in the centers of dwarf galaxies due to star formation and supernova feedback. These changes in the gas density profile are sufficient to change the central dark matter distribution, leading to the creation and maintenance of a flat core density profile. (Adapted from Figure 2 of Pontzen & Governato)

Next: (#10) A Magic Ratio to Quench Star Formation? Stellar and Dark Matter Mass tell Galaxies When to Stop Forming stars

Previous: (#12) Now you see them, now you don’t: Less Lyman-alpha emission from the oldest galaxies

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I am a 22nd-grader at UCLA, working with Mark Morris and spending the year at the MPIA in Heidelberg finishing my thesis. I like molecules in space, radio telescopes, the extreme center of our galaxy, getting to look at things no-one else has ever seen before, solving puzzles, and finding creative ways to survive graduate school

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Discussion

6 Responses to “The Top 12 of 2012”

  1. Hi Betsy:

    Just a note– it looks like the arXiv link that you have on the first page of this article does not link to the title you provide.

    The link looks like it goes here:

    http://arxiv.org/abs/1106.0499

    “How supernova feedback turns dark matter cusps into cores”

    instead of here:

    http://arxiv.org/abs/1107.1261

    “Keck Spectroscopy of Faint 3<z<8 Lyman Break Galaxies:- Evidence for a Declining Fraction of Emission Line Sources In the Redshift Range 6<z<8"

    Thanks,
    Dave

    Posted by Dave Coulter | February 20, 2013, 5:14 pm
  2. Fascinating articles! But counting citations seriously distorts what astronomy is about. Because most young astronomers today work in observational cosmology, 10/12 papers are on that topic, the most glamorous frontier. But 10/12 of the most significant new papers of 2012 (selected some other way) paint a certainly much broader canvas, and reflect the amazing scope of astronomical research!
    Only the search for new planets (another glamour topic) and new calculations of the evolution of rotating stars in the HR diagram (a classic issue in stellar astronomy) penetrated the top twelve. So much more was missing!
    Nonetheless, an interesting citation poll.

    Posted by Donald D Clayton | February 20, 2013, 7:39 pm
  3. Hi, I think the mass-to-light ratio of a low-mass star is higher than that of a high-mass star. In addition, the Salpeter IMF has more low-mass stars than the Kroupa and Chabrier IMFs.

    I think that the article in astrobites has more detail introduction:
    http://astrobites.com/2012/02/16/the-imf-is-not-universal/

    Posted by Song, Wang | February 20, 2013, 9:05 pm

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