Astronomers weigh the galaxy with the black hole

Astronomers used a new method for weighing a quasar. Among other things, this provides information about the formation of black holes. According to a study by the Swiss Federal Institute of Technology Lausanne (EPFL). In the journal «Nature Astrophysics».

Researchers have taken advantage of the fact that quasars act as a gravitational lens, EPFL announced Wednesday. According to the EPFL, this enabled them to determine the mass with three times greater accuracy than was possible before.

Gravitational lensing is a phenomenon in astrophysics. In this, the gravity of the massive object deflects and distorts the light from background sources. By analyzing the distortions, they were able to make precise measurements and determine the galaxy’s mass, according to EPFL.

A quasar is a very active, bright region in the center of the galaxy. It is a supermassive black hole.

This collects matter from its surroundings and releases massive amounts of energy in the process. Quasars are very bright and can shine billions of times brighter than our Sun.

This brightness, the researchers said, makes measurements of quasar galaxies difficult. Because the bright light of a quasar can dim or cover the light of the host galaxy.

Measurement with gravitational lenses solves this problem. But first, the researchers had to find a quasar that also acts as a gravitational lens.

According to the EPFL, a full decade passed between the idea of ​​weighing a quasar with gravitational lensing and the first results. Because gravitational lenses are very rare. According to the EPFL, they only occur in about one in a thousand galaxies.

Quasars can only be found in one galaxy out of a thousand. A lens quasar is found in only one of a million galaxies.