Dwarf galaxies imply dark matter is heavier than $\mathbf{2.2 \times
10^{-21}} \, \mathbf{eV}$
Dwarf galaxies imply dark matter is heavier than $\mathbf{2.2 \times
10^{-21}} \, \mathbf{eV}$
Folk wisdom dictates that a lower bound on the dark matter particle mass, $m$, can be obtained by demanding that the de Broglie wavelength in a given galaxy must be smaller than the virial radius of the galaxy, leading to $m\gtrsim 10^{-22}\text{ eV}$ when applied to typical dwarf galaxies. This …