Abstract
We use the state-of-the-art high-resolution cosmological simulations by IllustrisTNG to derive the velocity distribution and local density of dark matter in galaxies like our Milky Way and find a substantial spread in both quantities. Next we use our findings to examine the sensitivity to the dark matter velocity profile of underground searches using electron scattering in germanium and silicon targets. We find that sub-GeV dark matter search is strongly affected by these uncertainties, unlike nuclear recoil searches for heavier dark matter, especially in multiple electron-hole modes, for which the sensitivity to the scattering cross-section is also weaker. Therefore, by improving the sensitivity to lower ionization thresholds not only projected sensitivities will be boosted but also the dependence on the astrophysical uncertainties will become significantly reduced.
Highlights
This paper consists of two main parts: in section 2 we construct and discuss several DM profiles inferred from the Illustris simulation, while in section 3 we apply our findings to study their effect on electron recoil searches of DM with sub-GeV mass in semiconductor targets
The Standard Halo Model (SHM) is an isothermal, spherical dark halo with an isotropic Maxwell-Boltzmann (MB) dark matter velocity distribution with the dispersion velocity v0 in the Galactic rest frame and truncated at the escape speed from the Galaxy, fgal(v) = N exp −v2/v02 0 v < vesc, v ≥ vesc, (2.1)
In recent years by using more realistic high resolution cosmological simulations, which include baryonic physics effects, it was shown that the dark matter velocity distributions agree rather well with the SHM
Summary
As outlined in the introduction, dark matter velocity distribution is a crucial ingredient for estimating direct dark matter detection in the Milky Way. The true dark matter distribution could be different from what is normally assumed. One way to access the information on the properties of the DM halo is to examine the dark matter distribution of the MW analogues in the cosmological simulations. In recent years by using more realistic high resolution cosmological simulations, which include baryonic physics effects, it was shown that the dark matter velocity distributions agree rather well with the SHM. The local circular speed of the Maxwellian distribution and the escape velocity may well be different [48,49,50,51,52]. We present the resulting velocity distribution functions for some selected halos
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
