Bundle: Foundations of Astronomy, Enhanced, Loose-Leaf Version, 13th + MindTap Astronomy, 2 terms (12 months) Printed Access Card
13th Edition
ISBN: 9781337214353
Author: Seeds, Michael A., Backman, Dana
Publisher: Cengage Learning
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Question
Chapter 17, Problem 17RQ
To determine
The reason for large number of quasars is observed with intermediate redshift, while only few with low and high redshifts.
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Students have asked these similar questions
A Type la supernova explodes in a galaxy at a
distance of 6.10×107 light-years from Earth. If
astronomers detect the light from the
supernova today, how many years T have
passed since the supernova exploded? T=
2.07 x10 -5 years Given a Hubble constant of
74.3 km/s/Mpc, at what speed v is this galaxy
moving away from Earth? v= km/s What is
this galaxy's redshift? redshift:
What is the redshift of this quasar?
Suppose a quasar is shining with a luminosity L. What is the approximate minimal mass of the black hole? (If the black hole had a lower mass than this, the pressure in the material would overcome the gravity of the black hole and the material would be blown apart.) Give your answer in solar masses, in scientific notation to one significant figure (no decimal places).
Value:
L=1×10^12Lsun
Suppose the quasar in the previous problem is 10% efficient at turning rest mass into energetic photons, according to Einstein's equation E=mc2. What is the necessary rate of accretion of mass onto this black hole, to sustain its luminosity of 1* 1012 solar luminosities -- i.e. how much mass must be 'fed' to this black hole to keep the AGN shining so brightly?
Give your response in units of solar masses of material per year, with one decimal place.
Chapter 17 Solutions
Bundle: Foundations of Astronomy, Enhanced, Loose-Leaf Version, 13th + MindTap Astronomy, 2 terms (12 months) Printed Access Card
Ch. 17 - Prob. 1RQCh. 17 - Prob. 2RQCh. 17 - Prob. 3RQCh. 17 - Prob. 4RQCh. 17 - Prob. 5RQCh. 17 - Prob. 6RQCh. 17 - Prob. 7RQCh. 17 - Prob. 8RQCh. 17 - Prob. 9RQCh. 17 - Prob. 10RQ
Ch. 17 - Prob. 11RQCh. 17 - Prob. 12RQCh. 17 - Prob. 13RQCh. 17 - Prob. 14RQCh. 17 - Prob. 15RQCh. 17 - Prob. 16RQCh. 17 - Prob. 17RQCh. 17 - Prob. 18RQCh. 17 - Prob. 19RQCh. 17 - Prob. 20RQCh. 17 - Prob. 21RQCh. 17 - Prob. 1DQCh. 17 - Prob. 2DQCh. 17 - Prob. 3DQCh. 17 - Prob. 5DQCh. 17 - Prob. 6DQCh. 17 - Prob. 7DQCh. 17 - Prob. 1PCh. 17 - Prob. 2PCh. 17 - Prob. 3PCh. 17 - Prob. 4PCh. 17 - Prob. 5PCh. 17 - Prob. 6PCh. 17 - Prob. 7PCh. 17 - Prob. 8PCh. 17 - What is the change in the wavelength of the Balmer...Ch. 17 - Prob. 10PCh. 17 - Prob. 11PCh. 17 - Prob. 12PCh. 17 - Prob. 13PCh. 17 - Prob. 1LTLCh. 17 - Prob. 2LTLCh. 17 - Prob. 3LTLCh. 17 - Prob. 4LTLCh. 17 - Prob. 5LTL
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- What evidence do we have that the luminous central region of a quasar is small and compact?arrow_forwardRapid variability in quasars indicates that the region in which the energy is generated must be small. You can show why this is true. Suppose, for example, that the region in which the energy is generated is a transparent sphere 1 light-year in diameter. Suppose that in 1 s this region brightens by a factor of 10 and remains bright for two years, after which it returns to its original luminosity. Draw its light curve (a graph of its brightness over time) as viewed from Earth.arrow_forwardIf Hubble’s constant is taken to be 70 ??? ???, and a quasar is found to have a radial velocity equal to 95% of the speed of light, how far is the quasar in Mpc? (Hint: Use Hubble’s Law and solve for the distance; and the speed of light in vacuum is: ?=3.0×105 ??/?).arrow_forward
- Is a quasar with a redshift of z = 2 going faster than the speed of light? Why or why not?arrow_forwardThe hydrogen Balmer line H? has a wavelength of 486.1 nm. It is shifted to 536.0 nm in a quasar's spectrum. What is the redshift of this quasar? (Hint: What is Δ??)arrow_forwardThe time for a galaxy to cross from one side of a cluster to the other is called the crossing time. Find the crossing time for a galaxy moving at speed v to cross a cluster with a diameter d. Express you answer in gigayears, using one decimal place. Values: v = 849 km/s d = 1.3 Mpcarrow_forward
- When comparing two isolated spiral galaxies that have the same apparent brightness, but rotate at different rates, what can you say about their relative luminosity?arrow_forwardWhy are quasars generally so much more luminous (why do they put out so much more energy) than active galaxies?arrow_forwardCould the Milky Way ever become an active galaxy? Is it likely to ever be as luminous as a quasar?arrow_forward
- Why don’t any of the methods for establishing distances to galaxies, described in Galaxies (other than Hubble’s law itself), work for quasars?arrow_forwardIn the chapter, we discussed that the largest redshifts found so far are greater than 6. Suppose we find a quasar with a redshift of 6.1. With what fraction of the speed of light is it moving away from us?arrow_forwardWhy were quasars and active galaxies not initially recognized as being “special” in some way?arrow_forward
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