The elastic scattering between dark matter (DM) and radiation can potentially
explain small-scale observations that the cold dark matter faces as a
challenge, as damping density fluctuations via dark acoustic oscillations in
the early universe erases small-scale structure. We study a semi-analytical
subhalo model for interacting dark matter with radiation, based on the extended
Press-Schechter formalism and subhalos' tidal evolution prescription. We also
test the elastic scattering between DM and neutrinos using observations of
Milky-Way satellites from the Dark Energy Survey and PanSTARRS1. We
conservatively impose strong constraints on the DM-neutrino scattering cross
section of σDM-ν,n∝Eνn(n=0,2,4) at
95% confidence level (CL), σDM-ν,0<10−32cm2(mDM/GeV), σDM-ν,2<10−43cm2(mDM/GeV)(Eν/Eν0)2 and σDM-ν,4<10−54cm2(mDM/GeV)(Eν/Eν0)4, where Eν is the neutrino energy and Eν0
is the average momentum of relic cosmic neutrinos today, $E_\nu^0 \simeq 6.1\
{\rm K}.Byimposingasatelliteformingcondition,weobtainthestrongestupperboundsontheDM−neutrinocrosssectionat95\%CL,\sigma_{{\rm
DM}\text{-}\nu,0}< 4\times 10^{-34}\ {\rm cm^2}\ (m_{\rm DM}/{\rm GeV}),\sigma_{{\rm DM}\text{-}\nu,2}< 10^{-46}\ {\rm cm^2}\ (m_{\rm DM}/{\rm
GeV})(E_\nu/E_{\nu}^0)^2and\sigma_{{\rm DM}\text{-}\nu,4}< 7\times
10^{-59}\ {\rm cm^2}\ (m_{\rm DM}/{\rm GeV})(E_\nu/E_{\nu}^0)^4$.Comment: 19 pages, 7 figures. v2: Matches the published version in JCA