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We investigate the possibilities for probing MeV dark matter (DM) particlesand primordial black holes (PBHs) (for masses $\sim 10^{15}$--$10^{17}$ g) atthe upcoming radio telescope SKA, using photon signals from the Inverse Compton(IC) effect within a galactic halo. Pair-annihilation or decay of MeV DMparticles (into $e^+ e^-$ pairs) or Hawking radiation from a population of PBHsgenerates mildly relativistic $e^{\pm}$ which can lead to radio signals throughthe IC scattering on low energy cosmic microwave background (CMB) photons. Westudy the ability of SKA to detect such signals coming from nearby ultra-faintdwarf galaxies Segue I and Ursa Major II as well as the globular cluster$\omega$-cen and the Coma cluster. We find that with $\sim 100$ hours ofobservation, the SKA improves the Planck constraints on the DMannihilation/decay rate and the PBH abundance for masses in the range $\sim 1$to few tens of MeV and above $10^{15}$ to $10^{17}$ g, respectively.Importantly, the SKA limits are independent of the assumed magnetic fieldswithin the galaxies. Previously allowed regions of diffusion parameters of MeVelectrons inside a dwarf galaxy that give rise to observable signals at the SKAare also excluded. For objects like dwarf galaxies, predicted SKA constraintsdepend on both the DM and diffusion parameters. Independent observations indifferent frequency bands, e.g., radio and $\gamma$-ray frequencies, may breakthis degeneracy and thus enable one to constrain the combined parameter spaceof DM and diffusion. However, the constraints are independent of diffusionparameters for galaxy clusters such as Coma.

Constraints on MeV dark matter and primordial black holes: Inverse Compton signals at the SKA