A sub-component of dark matter with a short collision length compared to a planetary size leads to efficient accumulation of dark matter in astrophysical bodies. Such particles represent an interesting physics target since they can evade existing bounds from direct detection due to their rapid thermalization in high-density environments. In this talk, I will show that their annihilation to visible matter inside large-volume neutrino telescopes can provide a novel way to constrain or discover such particles. The signal is the most pronounced for relic masses in the GeV range, and can be efficiently constrained by existing Super-Kamiokande searches for dinucleon annihilation. I will also talk about possible neutrino signals from the annihilation of such dark matter particles, demonstrating that neutrino signals from the center of the Earth provide sensitivity to the unexplored parts of the parameter space. 

Stars have the potential to be excellent dark matter detectors; dark matter could heat them up, destroy them by forming black holes, or modify heat transport. To predict when and how this might happen, we need to compute the scattering rate of dark matter inside stars. In this talk, I will describe how, for a wide range of dark matter models, this requires taking into account collective effects - that is, coherent scattering with many particles inside the star. These effects have been neglected in many previous treatments; I will show how they can enhance or suppress naive predictions for dark matter scattering rates by orders of magnitude. Calculations can be performed systematically by computing in-medium effective propagators, using the apparatus of thermal field theory.

Stars and planets can be ideal playgrounds to discover dark matter. In this talk, I will review a range of dark matter searches using celestial objects, including exoplanets, solar-system planets, and our Sun. I will also discuss a new framework to describe what happens when dark matter is captured inside these objects, and the implications for dark matter search strategies.

Dark matter with light mass represents a challenge for direct detection as typical kinetic energy can be below 1 eV.  However, in some rare instances scattering on very energetic solar electrons can bring the DM particles to keV kinetic energies, opening the way for probing these models using the largest and cleanest Xe-based DM detectors. I describe our calculations and numerical simulations of the reflected flux and derive novel limits on light dark matter scattering on electrons. 

In this talk I will talk about my recent article where we propose a simpler way to combine the seesaw and the scotogenic approaches, by making dark matter the seed of neutrino mass generation within a low-scale seesaw mechanism. For definiteness we take the inverse seesaw as our template. I will discuss thoroughly both the possibilities of explicit as well as dynamical lepton number violation. For the case of dynamical lepton number violation I will discuss in some detail the phenomenology of invisible Higgs decays with majoron emission, as well as the phenomenology of scotogenic WIMP dark matter.