... can be measured and used as a ‘standard ruler’ for length scale in cosmology. For this, quasars powered by supermassive black holes at the centres of galaxies were used as they appear as a very bright point source in the distant past. Quasars...
...Quasars are a type of extremely luminous AGN. They derive their energy from material spiralling in towards an enormous black hole at the center of a galaxy forming a disk called an accretion disk. As the gas and dust spirals closer in, it accelerates...
... of these objects was debated for some time, it is now excepted that a quasar is the region around a supermassive black hole that emits up to a thousand times the energy output of the Milky Way through the accretion of matter. The...
... into a close orbit, eventually forming an X-ray binary. Nonetheless, in other cases, the kick could also produce black hole - neutron star (BH-NS) binaries with very short merger times. This could possibly give rise to a new type...
... waves - ripples in space and time that can be detected with extremely sensitive instruments on Earth. Since black holes and black hole mergers are completely dark, these events are invisible to telescopes and other light-detecting instruments used...
...the galaxy is due to the black hole, and only 0.1 percent could include stars, smaller black holes, interstellar dust and gas, or... Sagittarius A* or Sgr A* for short, was indeed a black hole, it was only after years of painstaking observations of the ...