Astronomy
1st Edition
ISBN: 9781938168284
Author: Andrew Fraknoi; David Morrison; Sidney C. Wolff
Publisher: OpenStax
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Textbook Question
Chapter 27, Problem 15E
A friend of yours who has watched many Star Trek episodes and movies says, “I thought that black holes pulled everything into them. Why then do astronomers think that black holes can explain the great outpouring of energy from quasars?” How would you respond?
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Observations of quasars have shown us that many are extremely _________, emitting more energy than all the stars in a galaxy. The energy they give off comes from a very small volume, typically about the size of ___________. Some have long ______, shooting off in opposite directions. Today, astronomers understand that all the properties of quasars can be explained if they are __________ at the centers of galaxies. Astronomers can use _____________ to study images and spectra of the central regions of galaxies more clearly than earlier instruments.
What is the Eddington luminosity of a quasar with a mass of 1 billion Msun ?
Describe a quasar.
Chapter 27 Solutions
Astronomy
Ch. 27 - Describe some differences between quasars and...Ch. 27 - Describe the arguments supporting the idea that...Ch. 27 - In what ways are active galaxies like quasars but...Ch. 27 - Why could the concentration of matter at the...Ch. 27 - Describe the process by which the action of a...Ch. 27 - Describe the observations that convinced...Ch. 27 - Why do astronomers believe that quasars represent...Ch. 27 - Why were quasars and active galaxies not initially...Ch. 27 - What do we now understand to be the primary...Ch. 27 - What is the typical structure we observe in a...
Ch. 27 - What evidence do we have that the luminous central...Ch. 27 - Suppose you observe a star-like object in the sky....Ch. 27 - Why don’t any of the methods for establishing...Ch. 27 - One of the early hypotheses to explain the high...Ch. 27 - A friend of yours who has watched many Star Trek...Ch. 27 - Could the Milky Way ever become an active galaxy?...Ch. 27 - Why are quasars generally so much more luminous...Ch. 27 - Suppose we detect a powerful radio source with a...Ch. 27 - A friend tries to convince you that she can easily...Ch. 27 - Show that no matter how big a redshift (z) we...Ch. 27 - If a quasar has a redshift of 3.3, at what...Ch. 27 - If a quasar is moving away from us at v/c=0.8 ,...Ch. 27 - In the chapter, we discussed that the largest...Ch. 27 - Rapid variability in quasars indicates that the...Ch. 27 - Large redshifts move the positions of spectral...Ch. 27 - Once again in this chapter, we see the use of...Ch. 27 - In the Check Your Learning section of Example...Ch. 27 - In the Check Your Learning section of Example...Ch. 27 - The quasar that appears the brightest in our sky,...
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Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, physics and related others by exploring similar questions and additional content below.Similar questions
- Describe the arguments supporting the idea that quasars are at the distances indicated by their redshifts.arrow_forwardWhy don’t any of the methods for establishing distances to galaxies, described in Galaxies (other than Hubble’s law itself), work for quasars?arrow_forwardWhy are quasars generally so much more luminous (why do they put out so much more energy) than active galaxies?arrow_forward
- 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*10^12 Lsunarrow_forwardSuppose 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.arrow_forward3C 273 was the first quasar identified (1963). When we look at its chemical spectrum, we see that its hydrogen alpha emission line (Hα) has an observed wavelength of λobs = 759 nm.-(By comparing the observed wavelength of Hα with the rest-frame (source) wavelength, find 3C 273’s redshift, z.- How fast is 3C 273 moving away from us in km/s?-Assuming the value of Hubble constant listed in the table at the top of the page, how far away is 3C 273 in Mpc? This was, at the time, the most distant object in the known universe!answer to three significant figuresarrow_forward
- Is the appearance of a quasar changing over time a sign that it has entered a new physical state, or are these objects just the extreme outliers of quasars at low activity?arrow_forwardWhat are the similarities and differences between blazars and quasars?arrow_forwardSuppose 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. Value: L = 1×1012Lsunarrow_forward
- What evidence do we have that quasars are a few parsecs or smaller in size?arrow_forwardWhat observation in astronomy, made AFTER the discovery of quasars, was a big help to astronomers in figuring out what quasars really were? 3 E O the discovery that the Milky Way Galaxy has a black hole at the center with enough mass for 4 million Suns O the understanding that most stars become white dwarfs when they die and white dwarfs are much smaller than main-sequence stars D O the discovery of exoplanets (planets orbiting other stars) throughout the Galaxy O the discovery that the galaxies mostly show a red shift O the discovery of Herbig-Haro objects around newly forming stars 4 F3 C $ 4 49 R F Q Search DII % 5 V F5 T G a V6 A F6 Y B * H F7 & PrtScn U N FB *00 8 J Home - F9 9 End K M F10 O Carrow_forwardWhy do we see most quasars at great distances?arrow_forward
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