Rapid growth of black holes accompanied with hot or warm outflows exposed to anisotropic super-Eddington radiation

We perform two-dimensional radiation hydrodynamical simulations of accretion flows on to a black hole (BH) with a mass of 10³ ≤ M_BH/ M_⊙ ≲ 10⁶ in order to study rapid growth of BHs in the early Universe. For spherically symmetric flows, hyper-Eddington accretion from outside the Bondi radius can occur unimpeded by radiation feedback when M_BH ≳ 10⁴ M_⊙(n_∞/10⁵ cm ^{- 3}) ^{- 1}(T_∞/10⁴ K)^3/2, where the density and temperature of ambient gas are initially set to n_∞ = 10⁵ cm^-3 and T_∞ = 10⁴ K. Here, we study accretion flows exposed to anisotropic radiation from a nuclear accretion disc with a luminosity higher than the Eddington value (L_Edd) due to collimation towards the bipolar directions. We find that, unlike the spherically symmetric case, even less massive BHs with M_BH < 10⁴ M_⊙ can be fed at high accretion rates of ≳ L_Edd/c² through the equatorial region, while ionized regions expand towards the poles producing hot outflows with T ∼ 10⁵ K. For more massive BHs with M_BH ≳ 5 × 10⁵ M_⊙, intense inflows of neutral gas through the equator totally cover the central radiating region due to the non-radial gas motions. Because of efficient recombination by hydrogen, the entire flow settles in neutral and warm gas with T ≃ 8000 K. The BH is fed at a rate of ∼5 × 10⁴L_Edd/c² (a half of the inflow rate from the Bondi radius). Moreover, radiation momentum absorbed by neutral hydrogen produces warm outflows towards the bipolar directions at ∼ 10 per cent of the BH feeding rate and with a velocity several times higher than the escaping value.