Spatially resolved rotation of the broad-line region of a quasar at sub-parsec scale

Understand

The broadening of atomic emission lines by high-velocity motion of gas near accreting supermassive black holes is an observational hallmark of quasars.

• Observations of broad emission lines could potentially constrain the mechanism for transporting gas inwards through accretion disks or outwards through winds.
• The size of this broad-line region has been estimated by measuring the light travel time delay between the variable nuclear continuum and the emission lines - a method known as reverberation mapping.
• In some models the emission lines arise from a continuous outflow, whereas in others they are produced by orbiting gas clouds.