Cosmological simulations of decaying dark matter: implications for small-scale structure of dark matter haloes

摘要: We present a set of N-body simulations class models in which an unstable dark matter particle decays into stable non-interacting m atter particle, with decay lifetime comparable to the Hubble time. study effects kinematic recoil velocity (Vk) received by on structures halos ranging from galaxycluster Milky Way mass scales. For Way-mass halos, we use high-resolution, zoomin explore Galactic substructure. In general, circular velocities magnitude kick are most strongly affected decays. show that decaying lifetimes 1 � H 0 and speeds Vk 20 40km/s can significantly reduce both abundance subh alos internal densities subhalos. also compare subhalo profiles observational constraints dwarf satellite galaxies. Interestingly, find do not violate current astrophysical constraints, mitigate well-documented “missing satellites problem” more recent “too big fail associated abundances Local Group A relatively unique feature late dec aying is they predict significant evolution as function This important consideration because at high redshifts, prior decays, exhibit same sequence structure formation cold matter. Thus, less constrained high-redshift phenomena (e.g., reionizati on, AGN formation, Lyman-α forest) than warm mark similar low-redshift predictions. conclude make predictions relevant for interpretation observations small galaxies be tested or kinematics well forthcoming large-scale surveys.