Speaker
Description
Pulsar Timing Array experiments can probe the presence of possible scalar
or pseudoscalar ultralight dark matter particles through decade-long timing of
an ensemble of galactic millisecond radio pulsars. If dark matter interacts only
gravitationally with ordinary baryonic matter, our findings show that ultralight
particles with masses 10$^{−24.0}$ eV $\leq$ m $\leq$ 10$^{−23.3}$ eV can have at most local density
ρ $\leq$ 0.3 GeV/cm$^{3}$. A conformal coupling of the dark matter scalar to gravity,
instead, would mediate an effective coupling between pulsars and dark matter.
In turn, this would produce a periodic modulation of the pulsar rotational fre-
quency. We present constraints on the coupling of dark matter, improving on
existing bounds.
