The Top 12 of 2012

5. Where are the Milky Way’s Predicted Massive Dwarf Galaxies?

Why it is important: Agreement between observations of our Galaxy’s satellites, and predictions from cosmological simulations of the evolution of dark matter halos, has been hard to come by, resulting in the so-called ‘missing satellites problem‘. This paper suggests these disagreements are far from over.

Lambda-CDM models predict there should be a lot of satellite galaxies with massive dark matter subhaloes orbiting our galaxy. Specifically, there should be more than ten with rotational velocities > 40 km/s (y-axis), indicating a large mass enclosed inside of its radius (x-axis). But so far, there is only one observed satellite (Draco) that might be anywhere near that massive (Figure 1 of Boylan-Kolchin et al.)

Next: (#4) Who’s the BOSS? New Measurements of the Cosmological Distance Ladder

Previous: (#6) Dark Matter Haloes: Now, Theoretically More Concentrated!

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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