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The Top 12 of 2012

4. New Measurements of the Cosmological Distance Ladder

Why it is important: If you want to know what is making our universe accelerate, you need excellent measurements of how it is accelerating. Specifically, you want to know the total amount the universe has expanded during the time photons traveled from distant sources (redshift) as a function of the current distances to these sources, and this requires either a standard candle or a standard ruler.

In this paper, new results from the Baryon Acoustic Oscillation experiment BOSS provide extremely tight constraints on the distances of galaxies (y-axis) in the very important redshift range (x-axis) when Dark Energy began to dominate the energy density of the universe. The BOSS results are also in good agreement with the WMAP model for a flat universe (shaded curve). (Figure 19 of Anderson et al.)

Next: (#3) We are Small, but We are Many! Kepler Measures an Increasing Frequency of Small Planets

Previous: (#5) The Satellites Are Still Missing… Where are the Milky Way’s Predicted Massive Dwarf 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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