What is the most likely source of energy for active galaxies and quasars?

What is the most likely source of energy for active galaxies and quasars?

The most probable energy source is the accretion of gas onto a supermassive black hole. At the heart of every active galaxy is a supermassive black hole. A `supermassive’ black hole, in this context, is one with a mass of 1 million to 10 billion Msun.

How many stars are in the galactic bulge?

10 million stars

What will you find at the center of the galactic bulge?

Bulge stars are generally more metal-rich and have a wider range of metallicities than stars in the metal-poor halo. There is also strong evidence that the bulges of large galaxies harbour supermassive black holes at their centres.

What does the galactic bulge contain?

Classical bulges These bulges are composed primarily of stars that are older, Population II stars, and hence have a reddish hue (see stellar evolution). These stars are also in orbits that are essentially random compared to the plane of the galaxy, giving the bulge a distinct spherical form.

How thick is the galactic disk?

First noticed in star counts, the thick disk contains about 10% of the stellar mass of the Milky Way and has a scale height of ~ 1,000 light years (the thin disk has a scale height of only ~ 400 light years). The greater scale height of the thick disk is the result of it being ‘kinematically hotter’ than the thin disk.

What can you find in the galactic disk?

Galactic disks are thin, basically circular distributions of stars, gas, and dust; this material moves on nearly circular orbits about a common center. Many disks exhibit beautiful spiral patterns as a result of this rotation, and some have pronounced bars crossing their centers.

What is the difference between population 1 and 2 stars?

Intermediate Population I stars (like the Sun) are located through the disk. They are slightly less metal rich. Population II stars are metal poor stars; they contain about 0.1 percent metals. Extreme Population II stars (the most metal poor) are found in the halo and the globular clusters; these are the oldest stars.