- •Contents
- •Preface
- •How to use this book
- •Chapter 1 Units, constants, and conversions
- •1.1 Introduction
- •1.2 SI units
- •1.3 Physical constants
- •1.4 Converting between units
- •1.5 Dimensions
- •1.6 Miscellaneous
- •Chapter 2 Mathematics
- •2.1 Notation
- •2.2 Vectors and matrices
- •2.3 Series, summations, and progressions
- •2.5 Trigonometric and hyperbolic formulas
- •2.6 Mensuration
- •2.8 Integration
- •2.9 Special functions and polynomials
- •2.12 Laplace transforms
- •2.13 Probability and statistics
- •2.14 Numerical methods
- •Chapter 3 Dynamics and mechanics
- •3.1 Introduction
- •3.3 Gravitation
- •3.5 Rigid body dynamics
- •3.7 Generalised dynamics
- •3.8 Elasticity
- •Chapter 4 Quantum physics
- •4.1 Introduction
- •4.3 Wave mechanics
- •4.4 Hydrogenic atoms
- •4.5 Angular momentum
- •4.6 Perturbation theory
- •4.7 High energy and nuclear physics
- •Chapter 5 Thermodynamics
- •5.1 Introduction
- •5.2 Classical thermodynamics
- •5.3 Gas laws
- •5.5 Statistical thermodynamics
- •5.7 Radiation processes
- •Chapter 6 Solid state physics
- •6.1 Introduction
- •6.2 Periodic table
- •6.4 Lattice dynamics
- •6.5 Electrons in solids
- •Chapter 7 Electromagnetism
- •7.1 Introduction
- •7.4 Fields associated with media
- •7.5 Force, torque, and energy
- •7.6 LCR circuits
- •7.7 Transmission lines and waveguides
- •7.8 Waves in and out of media
- •7.9 Plasma physics
- •Chapter 8 Optics
- •8.1 Introduction
- •8.5 Geometrical optics
- •8.6 Polarisation
- •8.7 Coherence (scalar theory)
- •8.8 Line radiation
- •Chapter 9 Astrophysics
- •9.1 Introduction
- •9.3 Coordinate transformations (astronomical)
- •9.4 Observational astrophysics
- •9.5 Stellar evolution
- •9.6 Cosmology
- •Index
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Astrophysics |
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9.6Cosmology
Cosmological model parameters
Hubble law |
vr = Hd |
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(9.83) |
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H(t) = |
R(t) |
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(9.84) |
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Hubble |
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R(t) |
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H(z) =H0[Ωm0(1 + z)3 + ΩΛ0 |
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parametera |
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+ (1 − Ωm0 − ΩΛ0)(1 + z)2]1/2 |
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Redshift |
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λobs − λem |
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R(tem) |
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λem |
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ds2 =c2 dt2 − R2(t) |
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Robertson– |
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Walker |
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metricb |
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+ r2(dθ2 + sin2 θ dφ2) |
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¨ |
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4π |
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ρ+ 3 |
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p |
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ΛR |
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R |
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GR |
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c |
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− 3 |
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c |
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Friedmann |
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equations |
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2 |
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8π |
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ΛR |
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R |
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GρR |
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− kc |
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3 |
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Critical |
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ρcrit = |
3H2 |
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(9.90) |
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density |
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8πG |
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ρ |
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8πGρ |
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Ωm = |
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(9.91) |
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ρcrit |
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Density |
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ΩΛ = |
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Λ |
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(9.92) |
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3H2 |
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parameters |
Ωk = − |
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kc2 |
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(9.93) |
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R2H2 |
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Ωm + ΩΛ + Ωk = 1 |
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(9.94) |
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Deceleration |
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¨ |
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Ωm0 |
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q0 = − |
R0R0 |
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(9.95) |
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parameter |
R˙02 |
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vr |
radial velocity |
HHubble parameter
dproper distance
0present epoch
Rcosmic scale factor
tcosmic time
zredshift
λobs |
observed wavelength |
λem |
emitted wavelength |
tem |
epoch of emission |
ds interval
cspeed of light
r,θ,φ comoving spherical polar coordinates
kcurvature parameter
Gconstant of gravitation
ppressure
Λcosmological constant
ρ(mass) density
ρcrit critical density
Ωm |
matter density parameter |
ΩΛ |
lambda density parameter |
Ωk |
curvature density parameter |
q0 |
deceleration parameter |
aOften called the Hubble “constant.” At the present epoch, 60 < H0 < 80kms−1 Mpc−1 ≡ 100hkms−1 Mpc−1, where h is a dimensionless scaling parameter. The Hubble time is tH = 1/H0. Equation (9.85) assumes a matter dominated universe and mass conservation.
b |
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that ds |
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c |
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≡ (d |
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Λ = 0 in a Friedmann universe. Note that the cosmological constant is sometimes defined as equalling the value |
used here divided by c2.
9.6 Cosmology |
185 |
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Cosmological distance measures
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tlb(z)light travel time from |
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Look-back |
tlb(z) = t0 − t(z) |
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an object at redshift z |
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time |
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t0 |
present cosmic time |
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t(z) cosmic time at z |
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dp |
proper distance |
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t0 dt |
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cosmic scale factor |
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distance |
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speed of light |
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dL = dp(1 + z) = c(1 + z) 0 |
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luminosity distance |
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Hubble parameterb |
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z |
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Flux density– |
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k |
curvature parameter |
aAssuming a flat universe (k = 0). The apparent flux density of a source varies as d |
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cDefined as the output power of the body per unit frequency interval. |
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dTrue for all k. The angular diameter of a source varies as d |
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Cosmological modelsa
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H(z) = H0(1 + z)3/2 |
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H |
Hubble |
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q0 = 1/2 |
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redshift |
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and Ωm0 = 1) |
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q |
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R(t) = R0(t/t0) |
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R |
cosmic scale |
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m0 |
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H0 |
0 [(1 + z )3 − 1 + Ωm0−1 ]1/2 |
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Ωm0 |
present mass |
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density |
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k |
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H(z) = H0[Ωm0(1 + z) + (1 − Ωm0)] |
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3(1 |
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q0 = 3Ωm0/2 |
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constant of |
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Ωm0 < 1) |
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t(z) = |
2 (1 Ωm0)−1/2 arsinh |
(9.110) |
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ρ |
mass density |
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3H0 |
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(1 + z)3/2 |
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aCurrently popular.