  By performing three-dimensional radiation hydrodynamics simulations, we study
Bondi-Hoyle-Lyttleton accretion onto intermediate-mass black holes (BHs)
wandering in the dusty gas. Here, we take into account the anisotropic
radiation feedback and the sublimation of dust grains. Our simulations show
that when the relative velocity between the BH and the gas is small (~20 km/s)
and gas density is ~10^4/cm^3, the gas mainly accretes from near the equatorial
plane of the accretion disk at a time-averaged rate of 0.6% of the
Bondi-Hoyle-Lyttleton rate. An ionized region like two spheres glued together
at the equatorial plane is formed, and the dense shock shell appears near the
ionization front. The BH is accelerated at ~10^-8cm/s^2 due to the gravity of
the shell. For denser gas (~10^6/cm^3), the time-averaged accretion rate is
also 0.6% of the Bondi-Hoyle-Lyttleton rate.However, the BH is decelerated at
~10^-7cm/s^2 due to gravity of the dense downstream gas although the dense
shock shell appears upstream. Our simulations imply that intermediate-mass BHs
in the early universe keep floating at > several 10km/s without increasing mass
in interstellar gas with density of ~10^4/cm^3, and slow down and grow into
supermassive BHs in galaxies with the density of ~10^6/cm^3.
