Bounds on Dark Matter annihilations from 21 cm data
  The observation of an absorption feature in the 21 cm spectrum at redshift
$z\approx 17$ implies bounds on Dark Matter annihilations for a broad range of
masses, given that significant heating of the intergalactic medium would have
erased such feature. The resulting bounds on the DM annihilation cross sections
are comparable to the strongest ones from all other observables.
