Quasar Time Delays

Quasars are objects in the universe that emit radio waves that can be detected. These quasars can be identified by their similar appearance to stars, and they exist as far away as distant galaxies. It has been postulated that some of these quasars exist at the center of some of these galaxies and interact with supermassive blackholes. Quasars can be powered by the energies released by supermassive blackholes from the absorption of matter and particles. Although quasars exist visibly at the center of galaxies, they are able to emit radio waves that expand outside of their galaxies. These radio waves are generated through a process where electrons at the center of the quasars approach the speed of light and interact with magnetic fields, allowing the electrons to travel in a helical fashion.

Quasars are also known to have high redshifts. A redshift occurs when an object's spectral lines shift to the red region of the wavelength spectrum. Redshift is equal to (λobs - λrest)/λrest where λobs is the observed wavelength, and λrest is the absorbed or emitted wavelength. The redshift value can be used to determine an object's distance. Also, for small recession velocities, the redshift is approximately equal to an object's recession velocity divided by the speed of light. A high redshift means a large distance, so quasars are very far away.

Astronomers have recently discovered a unique quasar that has five other similar-looking quasars near it that are all at the same distance. They also detected this quintuple quasar's time delays between flaring events. The time delays are important because they can be used to determine certain parameters that can help them understand things like the universe's age and expansion rate.

The image of the quintuple quasar is shown below where A-D is the quintuple quasar, and G1-G3 are galaxies:

Source: http://scitechdaily.com/astronomers-detect-time-delays-between-flaring-events-in-a-quasar/