Dark matter and dark energy The dark side of the universe

118 Pages·2005·21.84 MB·English

Dark matter and dark energy
The dark side of the universe
Anne Ealet
Lectures
• Lecture I
• Basis of cosmology
• An overview: the density budget and the concordance
model
• Lecture II
• The dark matter
• Lecture III
• The CMB
• Lecture IV
• The dark energy
2
Some basic references
• The seven papers of Wmap
Bennett et al, Spergel et al. , Verde et al, (2003) etc…
astro-ph/0302207 and 7 following…
• Wayne Hu thesis ’95 astro-ph/9507060
• Wayne Hu, Dodelson, astro-ph/0110414
• Lineweaver astro-ph/9702042
• Tegmark astro-ph/9511148
3
Lecture III:
1. The origin of the CMB, spectrum, history
2. Balloons, WMAP satellite and maps
3. The CMB power spectrum
4. Understanding main features, esp 1st peak
position
5. Extraction of cosmological parameters
6. Polarization
7. The future
The Fluctuations
An image of the Universe
at 380,000 years old
The CMB
(Cosmic Microwave Background)
The Structures
The History of CMB observations
1965
Discovery
e
t
i
s
b
e
w

P
COBE
1992 A
M
W

m
o
r
f

c
i
h
p
a
r
2003 WMAPG
• Predicted in 1948
G.Gamow
Discover accidently
in 1964 by
Penzias & Wilson
7
The Cosmic Background Explorer (COBE)
Temperature range 0-4 Kelvin
measured the temperature of the CMB
satellite- all sky
FIRAS: CMB has blackbody spectrum with T=2.728+/-0.004
Kelvin
DMR: temperature measurements with 7o beam
m
variation amplitude is 30+/-3 K
8
Isotropic 3K background.
The most perfect blackbody
we know
Dipole (3.4 mK).
Our motion relative to CMB
Primordial fluctuations
mK
20
9
The Cosmic Background Explorer
(COBE)
Dipole removed but emission
from galaxy still present
Our rest frame ? CMB rest frame
dipole anisotropy of ~0.1%
Foreground sources
most obviously our own Galaxy
Homogeneous early universe
CMB tells us about nature of universe at time of decoupling
recombination occurs when universe is ~300,000 years old
It is the first picture of the universe….
density uniform to ~1 part in 100,000 fluctuation are 10-5
10