Using the Milky Way satellites to study interactions between cold dark matter and radiation

Abstract

The cold dark matter (CDM) model faces persistent challenges on small scales. In particular, taken at face value, the model significantly overestimates the number of satellite galaxies around the Milky Way. Attempts to solve this problem remain open to debate and have even led some to abandon CDM altogether. However, current simulations are limited by the assumption that dark matter feels only gravity. Here, we show that including interactions between CDM and radiation (photons or neutrinos) leads to a dramatic reduction in the number of satellite galaxies, alleviating the Milky Way satellite problem and indicating that physics beyond gravity may be essential to make accurate predictions of structure formation on small scales. The methodology introduced here gives constraints on dark matter interactions that are significantly improved over those from the cosmic microwave background.

5 pages, 4 figures. V2: Matches version in MNRAS Letters

References in corpus (5)

• Too big to fail? The puzzling darkness of massive Milky Way subhaloes
• The Milky Way's Circular Velocity Curve to 60 kpc and an Estimate of the Dark Matter Halo Mass from Kinematics of ~2400 SDSS Blue Horizontal Branch Stars
• Hundreds of Milky Way Satellites? Luminosity Bias in the Satellite Luminosity Function
• Dark matter and cosmic structure
• On the Structure of Dark Matter Halos at the Damping Scale of the Power Spectrum with and without Relict Velocities

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• Abell 2744: Too much substructure for Lambda CDM?
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• ETHOS - an effective theory of structure formation: formation of the first haloes and their stars
• TASI 2014 Lectures: The Hunt for Dark Matter
• Structural properties of artificial halos in non-standard dark matter simulations
• Reducing cosmological small scale structure via a large dark matter-neutrino interaction: constraints and consequences
• Glow in the Dark Matter: Observing galactic halos with scattered light