Constraints on Dark Matter Microphysics from the Milky Way Satellite Population

By E. Nadler, V. Gluscevic, K. Boddy, Risa Wechsler. Astrophysical Journal, 2019

172 citations recorded by the source corpus.

Alternatives to the cold, collisionless dark matter (DM) paradigm in which DM behaves as a collisional fluid generically suppress small-scale structure. Herein we use the observed population of Milky Way (MW) satellite galaxies to constrain the collisional nature of DM, focusing on DM–baryon scattering. We first derive conservative analytic upper limits on the velocity-independent DM–baryon scattering cross section by translating the upper bound on the lowest mass of halos inferred to host satellites into a characteristic cutoff scale in the linear matter power spectrum. We then confirm and improve these results through a detailed probabilistic inference of the MW satellite population that marginalizes over relevant astrophysical uncertainties. This yields 95% confidence upper limits on the DM–baryon scattering cross section of 6 × 10−30 cm2 (10−27 cm2) for DM particle masses mχ of 10 keV (10 GeV); these limits scale as mχ1/4 for mχ ≪ 1 GeV and mχ for mχ ≫ 1 GeV. This analysis improves upon cosmological bounds derived from cosmic-microwave-background anisotropy measurements by more than three orders of magnitude over a wide range of DM masses, excluding regions of parameter space previously unexplored by other methods, including direct-detection experiments. Our work reveals a mapping between DM–baryon scattering and other alternative DM models, and we discuss the implications of our results for warm and fuzzy DM scenarios.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/c895741527696c9cd24d4320c9d23e675bcc7f79

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Citations in the corpus

Milky Way Satellite Census. I. The Observational Selection Function for Milky Way Satellites in DES Y3 and Pan-STARRS DR1 (2019, methodology): “The resulting cumulative number of satellites is slightly higher than predictions from some cosmological simulations (e.g., Newton et al. 2018; Nadler et al. 2019b), but lower than others (e.g., Kelley et al. 2019).”
Direct detection of strongly interacting sub-GeV dark matter via electron recoils (2019, unknown): “ned by CRESST-III [86] and CDEX (Migdal effect) [87], together with constraints from the X-ray Quantum Calorimeter experiment (XQC) [45], cosmic-rays (“CRDM”) [88], CMB [59], and Milky-Way satellites [89]. We do not show collider or beam-dump bounds, but see e.g. [90–92]. 4.2 Projections 4.2.1 Scali”