Strong constraints on decay and annihilation of dark matter from heating of gas-rich dwarf galaxies

Understand

Gas-rich dwarf galaxies located outside the virial radius of their host are relatively pristine systems and have ultra-low gas cooling rates.

• This makes them very sensitive to heat injection by annihilation or decay of dark matter (DM).
• Such dwarfs are particularly sensitive to DM producing e$^\pm$ with energies 1$-$100 MeV or photons with energies 13.6 eV$-1$ keV, because these products can be efficiently thermalized in the neutral hydrogen gas of the dwarfs.
• Following the methodology of Wadekar and Farrar (2021), we require the rate of heat injection by DM to not exceed the ultra-low radiative cooling rate of gas in the Leo T dwarf galaxy.