  We present a novel analytic model of relativistic wind accretion on to a
Schwarzschild black hole. This model constitutes a general relativistic
extension of the classical model of wind accretion by Bondi, Hoyle, and
Lyttleton (BHL). As in BHL, this model is based on the assumptions of steady
state, axisymmetry, and ballistic motion. Analytic expressions are provided for
the wind streamlines while simple numerical schemes are presented for
calculating the corresponding accretion rate and density field. The resulting
accretion rate is greater in the relativistic model when compared to the
Newtonian BHL one. Indeed, it is two times greater for asymptotic wind speeds
$v_\infty \ge 0.4\,\mathrm{c}$ and more than an order of magnitude greater for
$v_\infty \ge 0.8\,\mathrm{c}$. We have compared this full relativistic model
versus numerical simulations performed with the free GNU Public Licensed
hydrodynamics code AZTEKAS and found a good agreement for the streamlines in
the upstream region of the flow and also, to within 10 per cent, for the
corresponding accretion rates.
