Why are there few quasars at low redshifts and at very high redshifts but many at redshifts between about 2 and 3?
Why are there few quasars at low redshifts and at high redshifts but many at redshifts between about 2 and 3? Lower redshifts represent more recent times, when most smaller galaxies have been gobbled up and expansion of the universe has carried the galaxies away from each other.
Do quasars have high redshifts?
Most quasars have even larger redshifts. The record for “highest redshift quasar” has been frequently broken in recent years. At the time I wrote these notes, the record was held by a quasar with a redshift z=6.4.
Why do quasars have redshifts?
The high redshifts of the Quasars reflect a recession speed approches and exceed the speed of light, where those of Galaxies is very low compared to the Quasars.. At present, the most distant known galaxy with a spectroscopic redshift is EGSY8p7.
Do quasars have large or small redshifts?
The first quasars discovered looked like stars but had strong radio emission. Their visible-light spectra at first seemed confusing, but then astronomers realized that they had much larger redshifts than stars. The quasar spectra obtained so far show redshifts ranging from 15% to more than 96% the speed of light.
Why are nearby quasars so rare compared with distant quasars?
Why are nearby quasars so rare compared with distant quasars? Quasars can rejuvenate if more fuel comes from a colliding galaxy, like when the Milky Way and Andromeda will collide.
How does the brightness of a quasar compare with that of a large galaxy quizlet?
Quasars can be far more luminous than galaxies at comparable redshifts, but they are also physically far larger than galaxies. Multiple quasars with identical spectra and the same reshift, very near each other in the sky, generally are examples of gravitational lensing of light.
How does the spectrum of a quasar differ from that of an ordinary galaxy How do spectral lines help astronomers determine the distances to quasars?
How does the spectrum of a quasar differ from that of an ordinary galaxy? how do spectral lines help astronomers determine the distances to quasars? The spectrum of a quasar shows emission lines that are enormously redshifted. Astronomers determine the distances to quasars using these redshifts and the Hubble law.
What causes the redshifts we see in spectra of quasars quizlet?
What causes the redshifts we see in spectra of quasars? The spectra of quasars are redshifted by the expansion of the universe, rapidly increasing the distance between the quasars and the Milky Way. If the universe was infinitely old, light from stars at the end of every line of sight would eventually reach you.
Why are quasars so distant?
Why are quasars instead observed at far distances? A: The simple answer: because luminous quasars are still visible from large distances, while fainter active galactic nuclei (AGNs) are not. Quasars and other AGNs are distributed randomly in all directions over the sky but not in terms of distance.
How does the spectrum of a quasar differ from that of an ordinary galaxy?
How does the spectrum of a quasar differ from that of an ordinary galaxy? The spectrum of a quasar shows emission lines that are enormously redshifted. Astronomers determine the distances to quasars using these redshifts and the Hubble law.
Why do quasars vary?
Quasars vary in their luminosity on various time scales, from months, to weeks, and sometimes to days. It is because of their changes in luminosity on these time scales of months or even smaller amounts of time, that it is belived that the region where the energy is generated can be no larger than a few light months.
Why are most quasars so far away quizlet?
Why are most quasars so far away? There is a greater volume of the universe that is far away than is nearby and quasars were more abundant in the past when galaxies were close together. This image shows four quasars around a galaxy. The redshift of each of the four quasars is 0.0394 and greater than that of the galaxy.