The Top 12 of 2012

1. The Best and Biggest Look at the Gamma-ray Sky (So Far)

  • Title:  Fermi Large Area Telescope Second Source Catalog
  • Authors: P. Nolan, A. Abdo, M. Ackermann, et al.
  • First Author’s Institution: W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Stanford

Why it is important: We have known for a long time now what the sky looks like in visible, infrared, and even X-ray light.  Now, with the sensitivity and resolution of Fermi and other gamma ray telescopes, we are finally catching up at the highest energy regimes.

This paper introduces a gamma ray sky catalog with 1873 sources from 2 years of Fermi-LAT observations. Only 7% of  sources have clearly identified counterparts (red), while 63% have probable associated counterparts (blue). The majority of associated or identified sources are AGN or blazars (84%). The next most common are pulsar wind nebulae and supernova remnants at 5% (Adapted from Figure 17 of Nolan et al). 

There you have it! The top 12 papers from last year (so far). What have we learned? Well, besides the fact that the subjects of these papers (much like the composition of our universe) are mostly dark matter or dark energy, we can see that our understanding of the universe we live in is constantly changing. Better views and models are constantly coming around so quickly that even here at Astrobites, it is hard to keep up with it all! Here’s to another year of the new viewpoints that keep science fun.

Previous: (#2) Let There be Dark? Constraining Dark Energy at high redshifts

About Betsy Mills

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


  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:

    “How supernova feedback turns dark matter cusps into cores”

    instead of here:

    “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"


    • Ah, actually the links are just switched–


      • Thanks Dave! The links are now fixed.

  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.

    • Yes, I had the mass-to-light ratio section entirely backward; this is now corrected (and consistent with the linked astrobite). Thank you!!


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