The Effect of Accretion Environment at Large Radius on Hot Accretion Flows

الأصل · EN

We study the effects of accretion environment (gas density, temperature and angular momentum) at large radii (10pc) on luminosity of hot accretion flows. The radiative feedback effects from the accretion flow on the accretion environment are also self-consistently taken into account. We find that the slowly rotating flows at large radii can significantly deviate from Bondi accretion when radiation heating and cooling are considered. We further find that when the temperature of environment gas is low (e.g. T=2× 10⁷K), the luminosity of hot accretion flows is high. When the temperature of gas is high (e.g. T≥4× 10⁷K), the luminosity of hot accretion flow significantly deceases. The environment gas density can also significantly influence the luminosity of accretion flows. When density is higher than 4× 10⁻²²g cm⁻³ and temperature is lower than 2× 10⁷K, hot accretion flow with luminosity lower than 2%LEdd is not present. Therefore, the pc-scale environment density and temperature are two important parameters to determine the luminosity. The results are also useful for the sub-grid models adopted by the cosmological simulations.