Black Holes, Quasars, Galaxies, Accretion Disks and the Winds that Blow Them

Rochester Institute of Technology scientists have for the first time observed the winds of gas that shoot from the center of quasar galaxies and that are associated with supermassive black holes and, in fact, regulate the black hole's growth.

It has been theorized for a long time that winds of gas from quasar galaxies are launched from and powered by accretion disks around black holes and that they regulate the growth of black holes. But since quasars and accretion disks are undetectable in visible light, no confirming evidence has ever been collected to prove the theory. Until now.

Scientists Stuart Young, David Axon and Andrew Robinson from the Rochester Institute of Technology, along with colleagues James Hough and James Smith from the University of Hertfordshire in England used the William Herschel Telescope on the Canary Islands to examine quasar galaxy PG 1700+518, located 3 billion light years from Earth, by using a technique called polarimetry.

The Herschel Telescope has capabilities for both optical and infrared imaging. Polarimetry is a technique specialized in at the University of Hertfordshire and is defined as the measurement of the polarization of light, x-rays or radio waves (electromagnetic radiation) as they pass through or refract off of a gas or liquid or surface. In the case of quasar galaxies, it would be light passing through gases associated with accretion disks and explusion jets of gas also called quasars around the black hole in the center of the quasar galaxy: polarized light or other electromagnetic radiation takes different directions while exhibiting different properties and specialized imaging can detect this.