COSMOLOGY 566 Astrophysical Constraints on Particle Physics

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COSMOLOGY 566Astrophysical Constraints on
Particle Physics

• Lawrence M. Krauss
• CWRU
• Jan 23- May ? 2002

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Tentative Topics (7 sessions)

• Astrophysics Constraints, FRW Expansion and Age
  of the Universe
• Density of the Universe Dark MatterDark Energy
  
• Nucleosynthesis Constraints
• Stellar Evolution
• Baryogenesis and Inflation
• Large Scale Structure and CMB
• Gravitational Waves

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TERM PLAN

• No make up classes
• Term assignments will be handed out Feb 20
  Students will work in groups 2 and prepare a
  paper and lecture on astrophysical implications
  of a particle scenario. I will choose as many
  different scenarios as there are groups.. Each
  one will have different astrophysical
  implications.
• No classes Feb 27-March 27
• April 17 -May 2nd, student presentations

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1 Outline

• Why Cosmology?
• Observables
• Homogeneity-Number Counts
• FRW and Einsteins Equations
• Hubble Constant Estimates
• Age-Redshift Relation

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1 Why Cosmology?
The Universe as (a) Accelerator (b)
target (c) laboratory
The Discovery Potential of Astrophysics is
immense, as new windows on the Universe are
opening up.
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1 Why Cosmology?
The Observables

• Expansion Rate
• Distance (luminosity, size, age)-redshift
  relation
• Mass Density
• Stellar Luminosities and Distribution
• Large Scale Structure
• Light Element Abundance
• Baryon to Photon Ratio
• Cosmic Microwave Background
• X Ray, Gamma Ray and Gravitational Wave
  Backgrounds
• Dark Matter Density and Distribution
• Dark Energy Density and Distribution
• Neutrino Background

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1 Why Cosmology?
QCD, SUSY?
106 103 100 10-3
LHC
Ecm (GeV)
t
Fermilab
W,Z
CERN
QCD
SLAC, BNL
1975 1985 1995 2005 2015
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1 Why Cosmology?
COSMIC RAYS
BARYONS?
SN
QCD, SUSY?
106 103 100 10-3
DARK MATTER?
LHC
Ecm (GeV)
EW PT
t
BBN
Fermilab
W,Z
CERN
QCD
QCD PT
SLAC, BNL
1975 1985 1995 2005 2015
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1 Why Cosmology?
Luminosity (erg/sec)
eg. CERN 1999 lt I gtbeam 4mA 1016 e/sec
lt E gtbeam 100 GeV 10-1 erg -gt L 1015 erg/sec
108 W
Compare to Earth 1013 W 1020
erg/sec Sun 1033 erg/sec AGN-Quasar
1045 erg/sec Supernova 1053 erg/sec
Astrophysics Rules!!!
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1 Why Cosmology?
Astrophysics
CROSS SECTION
10-42 10-40 10-38 10-36 10-34
? (cm2)
Accelerators
1 10 102 103 104 105 106
(cm)
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1 Why Cosmology?
Target Volumes (MASS)
108 USD 105 Tons
1022
1 SUN 1027 Tons
Interaction Regions LHC/BNL (1 fm)3 at T
100 MeV
1057
Supernova (1019 fm)3 at T 100 MeV
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1 Why Cosmology?
Caveats

• An Observation is NOT an experiment!
• Systematics are EVERYTHING!
• Beware of Over-interpreting the data

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2 The standard model
The Standard Model of cosmology in the 1980s,
developed by a remarkable interplay of ideas from
particle theory, along with particle experiments,
and observations from astrophysics
IS DEAD..
It has been replaced by something far more
bizarre..
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2 The standard model
The Universe is
ISOTROPIC
Homogeneous
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return
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2 The standard model
Hubble (1926) (Euclidean Universe)
Apparent Magnitude
Hence, if no edge, etc
For curvature, Expansion, See Weinberg, Peebles
DATA
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2 The standard model
The Universe is
ISOTROPIC
Homogeneous
1 QUANTITY DESCRIBES UNIVERSE
R(t)
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2 The standard model
General Relativity The most general possible
metric describing an isotropic homogeneous
universe with R(t)
k curvature 0 flat 1 closed -1
open
Only dimensional quantity sets Scale of the
Universe..The most important number in nature?.
Dynamics of R(t) governed by Einsteins
Equations
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2 The standard model
Einsteins Equations
First order
(1)
Second order
(2)
where wi determines the equation of state of
the ith component p w ?
What is physical significance of each equation?
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2 The standard model
Relates Expansion of the Universe to mean
energy density and curvature
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Expansion of the Universe
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Expansion of the Universe
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Galaxies at t1
Galaxies at t2
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2 The standard model
Relates Expansion of the Universe to mean
energy density and curvature
v
Imagine a region small compared to the size of
the Universe, but large enough to be uniform..
R

• vHr and v ltltc -gt
• Relativity irrelevant
• 2. Isot. plus homo. imply that whatever happen
  to this region will happen to whole Universe

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How will the Universe End?

-
ET gt0 escape ETlt 0 return
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How will the Universe End?
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EINSTEINS FIRST ORDER EQUATION !
2ET/mR2 - ? CURVATURE!!!
Open Universe klt0 Egt0 Flat Universe
kE0 Closed Universe kgt0 Elt0
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Geometry Destiny!
Closed Universe Recollapse Open Universe
Expand forever Flat Universe Just at the
edge of collapse
. More later
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2 The standard model
Second order
(2)
Equivalent to first order E.E., PLUS addition of
Conservation of Energy dE -pdV. This
latter condition can be rewritten, and governs
dynamical behavior of various energy densities.
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2 The standard model
For isotropic universe
Matter
Radiation
Matter ultimately dominates over
radiation.. Radiation dominates early on
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Geometry Destiny
A
B
C
For matter and radiation
(i) B -gt expansion decelerates
(ii) aboveA -gt if k0 (open or flat) H2 gt0 for
all time.
B C -gt ??decreases faster than R-2
If k gt 0 (closed), A(I) -gt turning point with
H0, d2R/dt2 lt0
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2 The standard model
Define
Problem 1 Prove this
? determines the future! The chief goal of
observational cosmology in the 20th century!
FLATNESS PROBLEM!!! Why is ? close to 1 today?
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2 The standard model
Define
Deceleration Parameter
Problem 2 Prove
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Geometry ?Destiny!!!
A
B
C
For matter and radiation
Vacuum Energy violates the SEC (w-1)!
Anything possible!
By Lorentz invariance
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Geometry ?Destiny!!!
1. If Expansion Rate gt0 when empty space
dominates it will remain gt0 forever, whether the
Universe is Open or Closed.
2. If present observation is incorrect, so empty
space energy does not dominate, even if universe
is Closed, it may expand forever
W lt1.1 today Rmax- gt11 Rtoday
But normal energy density falls as 1/R3 \ if
energy of empty space is gt 1/1000 energy of
present normal energy density, universe
will expand forever!
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Geometry ?Destiny!!!
3. If present observation is incorrect, and
Universe is Open, it need not expand forever
V
Recollapse even if ?? exp (-1000) today
4. If present observation is correct, the
universe need not expand forever.
Dark energy.
LMK and MST no finite set of observations good
enough
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3. Observational Cosmology..
(1) Measure H0
(2) Measure ?
(3) Determine Eternity
(1) H0 vHr
How to measure r ?
Standard Candles (i) Variable Stars
Cepheid, RR Lyrae
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Hubbles Data!
H 500 km/s/Mpc
Only a factor of 10 wrong!
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• HST-Key Project Use Cepheid Distances to 25
  Galaxies within 25 Mpc to calibrate secondary
  distance indicators
• Tully Fisher (spirals)
• fundamental plane (ellipticals)
• Surface Brightness fluctuations
• Sn 1a

Then use each to measure H0
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H0 70 7 km/s/Mpc
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Other Standard Candles?
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H0 658
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Direct measures?

• SZ Effect

Cosmic Microwave Background scattering on
intervening Galaxy Cluster matter (hot
electrons) -gt shift to higher energy
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SZE
Compare to X-Ray intensity
Use models to determine ne, ne2 .
Derive dl
Physical size
Compare to angular size -gt Distance measure
(assume perp tang.. -gt statistical)
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(2) Gravitational Lensing
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(2) Gravitational Lensing
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(2) Gravitational Lensing
A
B
C
D
AB -CD d TIME DELAY!
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BUT, DOMINANT EFFECT NOT GEOMETRY, RATHER,
GENERAL RELATIVITY!
SHAPIRO EFFECT TIME DELAY DUE TO TRAVEL IN
GRAVITATIONAL POTENTIAL!
H0 69 15
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H0 63 -77
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4. Hubble Age.
If the Universe is decelerating t lt H-1
VHd
td/vH-1
For constant velocity
More generally
Problem 3 Show
a
Flat matter dominated
b
Flat rad. dominated
Flat, matter W0 plus Dark energy Wx
c
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4. Hubble Age.
Note for a cosmological constant
(greater than H-1 because universe Accelerating!)
Also note
For a flat matter dom. U
While for a cosmological constant dominated
universe the Z dependence is different for z a
few! (ref Ap. J. 480, 466)
Thus, limits on H give limits on t! Compare to
other estimates of t to constraint cosmology