A galaxy.
It's not "galaxy stars", but galaxies, that have the black holes at their center.All, or most, galaxies have a giant black hole at their center.
The best evidence for a supermassive black hole in the center of the Milky Way galaxy comes from observations of the orbits of stars near the galactic center. These stars move at high speeds around an invisible object with a mass millions of times that of the Sun, indicating the presence of a supermassive black hole.
Stars, nebula, and a super-massive black hole at it's center.
Astronomers suspect that a super massive black hole is at the center of the Milky Way. Over a period of several years, astronomers have observed that stars near the center of the Milky Way are orbiting an object with massive gravitation, and the object emits no light. What can it be? A black hole is the best answer, and by the way the stars move, it must a super massive one.
All galaxies have supermassive black holes in their centers.
Any star that gets too close to a black hole can be drawn into it. But most stars can orbit the center of the galaxy almost indefinitely, without such a thing happening.
Fortunately, no.
because the black holes that they think are at the center of galaxies most likely have rotation, and the stars around it orbit the black hole somewhat like an accretion disc.
No, but some stars end their life by becoming a black hole.
The best evidence for an extremely massive black hole in the center of the Milky Way is the observation of stars orbiting around a region called Sagittarius A. The high speeds at which these stars are moving can only be explained by the presence of a supermassive object, like a black hole, with a mass of about 4 million times that of our Sun.
The center of many galaxies is suspected to house a "supermassive black hole". The black hole may even weigh more than all the stars in that galaxy combined. Spiral galaxies are more likely to contain a supermassive black hole.
A singularity is at the centre of a black hole.