Black hole winds

Abstract

We show that black holes accreting at or above the Eddington rate probably produce winds that are optically thick in the continuum, whether in quasars or in X-ray binaries. The photospheric radius and outflow speed are proportional to 2 out and -1 out respectively, where out is the mass outflow rate. The momentum outflow rate is always of the order of L Edd /c. Blackbody emission from these winds may provide the big blue bump in some quasars and active galactic nuclei, as well as ultrasoft X-ray components in ultraluminous X-ray sources.