Small-Scale Challenges to the ΛCDM Paradigm: Figure 7b

A video from the 2017 review by James S. Bullock and Michael Boylan-Kolchin, "Small-Scale Challenges to the ΛCDM Paradigm," from the Annual Review of Astronomy and Astrophysics.

The missing satellites problem: predicted ΛCDM substructure (a) versus known MW satellites (b). Panel b (by M. Pawlowski in collaboration with the authors) shows the current census of MW satellite galaxies, with galaxies discovered since 2015 in red. The Galactic disk is represented by a circle of radius 15 kpc at the center, and the outer sphere has a radius of 250 kpc. The 11 brightest (classical) MW satellites are labeled by name. Sizes of the symbols are not to scale but are rather proportional to the log of each satellite galaxy's stellar mass. Currently, there are ∼50 satellite galaxies known in the MW as compared to thousands of predicted subhalos with M _peak≳10⁷M_⊙. Abbreviations: dSph, dwarf spheroidal; LMC, Large Magellanic Cloud; MW, Milky Way; SMC, Small Magellanic Cloud.