Universe: Stars And Galaxies
6th Edition
ISBN: 9781319115098
Author: Roger Freedman, Robert Geller, William J. Kaufmann
Publisher: W. H. Freeman
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Chapter 23, Problem 18Q
To determine
Importance of Type Ia supernova when finding the distances to very remote galaxies and the limitations of using Type Ia supernova in this process.
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Students have asked these similar questions
An observational survey of distant galaxies is undertaken that involves measuring their
distances using cepheid variables and red-shifts using spectroscopy. Explain how cepheid
variables can be used to measure the distances to galaxies.
A spectral line is observed whose wavelength in the laboratory is de
length of this spectral line observed in each galaxy, Xo, is listed in the table, along with
the distance, d, to the galaxy. Determine the red-shift and the recession velocity of each
galaxy and tabulate your results by making a copy of the table and filling in the blank spaces.
Sketch a Hubble diagram using your results and determine the value of the Hubble constant
Ho in units of km s-1 Mpc.
650 nm. The wave-
Galaxy 1
652.69
Galaxy 2 Galaxy 3 Galaxy 4 Galaxy 5
653.01
do (nm)
d (Mpc)
658.54
662.18
681.63
17
19
54
77
200
v (km s-1)
Consider a galaxy with a density profile of the type
Ро
p(r)
=
(r/ro)[(1+r/ro)²] '
where po is the central density.
1. In a sentence describe what ro represents.
2. Find the mass profile M(r) for such a galaxy.
3. Find the circular velocity profile (r) for such a galaxy.
How astronomers determine the distance of a galaxy? Explain.
Chapter 23 Solutions
Universe: Stars And Galaxies
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- What are the characteristics of an E7 Galaxy? What about E0 galaxy? Explain.arrow_forwardA galaxy with a spherically symmetric distribution of matter has a mass density profile of the type p(r) ∞ 1/r, where r is the radial coordinate from the centre of the galaxy. To what type of circular velocity (r) does this correspond? Select one: a. (r) O b. c. O d. (r) ~ r (r) ~ √r (r): = constantarrow_forwardIndicate whether the following statements are true or false. (Select T-True, F-False. If the first is T and the rest F, enterTFFFFF). A) The three main classifications of galaxies are elliptical, spiral and prime.B) The mass of a spiral galaxy can be found from its rotational velocity. The greater the rotation, the greater the mass.C) Galaxies sometimes collide with each other.D) It wasn't until the 1920s that we knew the Milky Way was only one of many galaxies.E) Most galaxies are elliptical.F) The shorter the pulsation period of a Cepheid variable star, the more luminous it is.arrow_forward
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