21st Century Astronomy 6E
6th Edition
ISBN: 9780393690675
Author: Laura Kay, Stacy Palen, George Blumenthal
Publisher: W. W. Norton
expand_more
expand_more
format_list_bulleted
Concept explainers
Question
Chapter 19, Problem 39QP
To determine
The lifetime of quasar.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
Problem 2: Black hole – the ultimate blackbody
A black hole emits blackbody radiation called Hawking radiation. A black hole with mass
M has a total energy of Mc², a surface area of 167G²M² /c*, and a temperature of
hc³/167²KGM.
a) Estimate the typical wavelength of the Hawking radiation emitted by a 1 solar
mass black hole (2 × 103ºkg). Compare your answer to the size of the black hole.
b) Calculate the total power radiated by a one-solar mass black hole.
c) Imagine a black hole in empty space, where it emits radiation but absorbs nothing.
As it loses energy, its mass must decrease; one could say "evaporates". Derive a
differential equation for the mass as a function of time, and solve to obtain an
expression for the lifetime of a black hole in terms of its mass.
An astronomical image shows two objects that have the same apparent magnitude, i.e., the same brightness. However, spectroscopic follow up observations indicate that while one is a star that is within our galaxy, at a distance dgal away, and has the same luminosity as the Sun, the other is a quasar and has 100x the luminosity of the entire Milky Way galaxy. What is the distance to the quasar? (You may assume, for this rough calculation, that the Milky Way has 1011 stars and that they all have the luminosity as the Sun.) Give your response in Mpc. Value: dgal = 49 pc
Do it asap
Chapter 19 Solutions
21st Century Astronomy 6E
Ch. 19.1 - Prob. 19.1ACYUCh. 19.1 - Prob. 19.1BCYUCh. 19.2 - Prob. 19.2CYUCh. 19.3 - Prob. 19.3CYUCh. 19.4 - Prob. 19.4CYUCh. 19 - Prob. 1QPCh. 19 - Prob. 2QPCh. 19 - Prob. 3QPCh. 19 - Prob. 4QPCh. 19 - Prob. 5QP
Ch. 19 - Prob. 6QPCh. 19 - Prob. 7QPCh. 19 - Prob. 8QPCh. 19 - Prob. 9QPCh. 19 - Prob. 10QPCh. 19 - Prob. 11QPCh. 19 - Prob. 12QPCh. 19 - Prob. 13QPCh. 19 - Prob. 14QPCh. 19 - Prob. 15QPCh. 19 - Prob. 16QPCh. 19 - Prob. 17QPCh. 19 - Prob. 18QPCh. 19 - Prob. 19QPCh. 19 - Prob. 20QPCh. 19 - Prob. 21QPCh. 19 - Prob. 22QPCh. 19 - Prob. 23QPCh. 19 - Prob. 24QPCh. 19 - Prob. 25QPCh. 19 - Prob. 26QPCh. 19 - Prob. 27QPCh. 19 - Prob. 28QPCh. 19 - Prob. 29QPCh. 19 - Prob. 30QPCh. 19 - Prob. 31QPCh. 19 - Prob. 32QPCh. 19 - Prob. 33QPCh. 19 - Prob. 34QPCh. 19 - Prob. 35QPCh. 19 - Prob. 36QPCh. 19 - Prob. 37QPCh. 19 - Prob. 38QPCh. 19 - Prob. 39QPCh. 19 - Prob. 40QPCh. 19 - Prob. 41QPCh. 19 - Prob. 42QPCh. 19 - Prob. 43QPCh. 19 - Prob. 44QPCh. 19 - Prob. 45QP
Knowledge Booster
Learn more about
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
- velocity curve for a double line spectroscopic binary is shown in the sketch. The system is viewed edge-on, i.e., with an inclination angle of i 90°, so that the maximum possible Doppler shifts for this system are observed. 400 SPo = , Ain i 300 200 l0o = v Ain i 100 -100 -200 -300 400 0 1 2 3 4 10 Time (days) Find the speed of star 2 in km/s. Doppler Velocity (2esu)arrow_forwardA galaxy is found to be receding at a velocity of 3.0 x 104 km-s-1. Calculate the distance to the galaxy.arrow_forwardWhat is the orbital period (in s) of a bit of matter in an accretion disk that is located 6 ✕ 105 km from a 99 M black hole? Hint: Use the circular orbit velocity formula, Vc = GM r . sarrow_forward
- A Cepheid variable in the Andromeda galaxy has a period of 22 days and a mean apparent magnitude of19.5.(a) Calculate the distance modulus of the Andromeda galaxy.(b) Given that the Andromeda galaxy is approaching the Milky Way with a velocity of 119 km/s, roughlyestimate how long before these two galaxies collide? Provide your answer in years.arrow_forwardConsider a Schechter luminosity function of the form where a = 0.9, ΦΣ = -0 (L)dL = D(+) L e-(L/Lx)dL, L 0.012h3 Mpc3 and L - 1010h Lo. Calculate the total number density. Express the final answer in terms of h where h = Ho/(100 km s−¹Mpc¯¹) (Ho is the Hubble constant).arrow_forwardFor the Galactic Center black hole (Sag. A*), which has mass ~4.1 million solar masses, find the maximum luminosity that could be emitted via spherical accretion of ionized gas (i.e., the Eddington limit LEdd). Express your answer as a multiple of the Qmlaxy's total luminous output, = 2.5 x 1010 L. LMW (i.e., enter the ratio LEdd/LMw).arrow_forward
- Time left 1:45:56 A star has initially a radius of 680000000 m and a period of rotation about its axis of 33 days. Eventually it changes into a neutron star with a radius of only 45000 m and a period of 0.3 s. Assuming that the mass has not changed, find Assume a star has the shape of a sphere. (Suggestion: do it with formula first, then put the numbers in) [Recommended time : 5-8 minutes] (a) the ratio of initial to final angular momentum (Li/Lf) Oa. 2.17E+15 Ob. 24 Oc. 0.0416 Od. 4.61E-16 (b) the ratio of initial to final kinetic energy Oa. 4.85E-23 Ob. 396000 Oc. 2.53E-6 Od. 2.06E+22arrow_forwardThe Kormendy relation for ellipticals can be written as He = 20.2+ 3.0 log R. where R. is the half-light radius (in kpc) and 4e is the surface brightness (in magnitudes per square arc second) at R.. An elliptical galaxy obeying this relation will have a total luminosity Lo R for some index 7. What is the correct value of n? O a. n=-6/5 O b. n= 4/5 T23D Oc n= 16/5 O d. n cannot be determined with the information we have.arrow_forwardHow many galaxies like our own would it take if they were placed edge-to-edge to reach the nearest galaxy? (Hint: See Problems 11 and 12.)arrow_forward
- Suppose that a galaxy has 109 M⊙ of neutral HI gas with a temperature of about 10 K. Estimate the luminosity of the 21 cm wavelength radiation that is expected from the galaxy. Answer in watts.arrow_forwardwhat is the answer for sub-item (b) if the radius of the neutron star is 84.66 km?arrow_forwardWhat is the ratio of the percent of metals in extreme Population I stars (3%) to that in extreme Population II stars (0.05%)? NpopI NpopII =arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Foundations of Astronomy (MindTap Course List)PhysicsISBN:9781337399920Author:Michael A. Seeds, Dana BackmanPublisher:Cengage Learning
Stars and Galaxies (MindTap Course List)PhysicsISBN:9781337399944Author:Michael A. SeedsPublisher:Cengage Learning
Foundations of Astronomy (MindTap Course List)
Physics
ISBN:9781337399920
Author:Michael A. Seeds, Dana Backman
Publisher:Cengage Learning
Stars and Galaxies (MindTap Course List)
Physics
ISBN:9781337399944
Author:Michael A. Seeds
Publisher:Cengage Learning