The cosmic background radiation II: The WMAP...
Transcript of The cosmic background radiation II: The WMAP...
![Page 1: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/1.jpg)
The cosmic background radiation II:The WMAP results
Alexander Schmah 27.01.05
![Page 2: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/2.jpg)
General Aspects
- WMAP measures temperatue fluctuations of the CMB around 2.726 K - Reason for the temperature fluctuations are density fluctuation in the early universe
- The CMB comes from the age of the decoupling of the photons from the matter
- The CMB data is described with cosmological models
![Page 3: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/3.jpg)
WMAP: Overview
Wilkinson Microwave Anisotropy Probe: WMAP
-Named after Dr. David Wilkinson, pioneer in the study of CMB and member of the science team, died in September 2002
- WMAP weight: 840 kg
-Angular resolution: 0.3°
- Sensitivity: 20 K/(0.3°)2
![Page 4: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/4.jpg)
Launch
Launch of the Delta II rocket on 30 June 2001
![Page 5: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/5.jpg)
Measuring position
Orbit around the second Lagrange point (L2) of the Earth-Sun system
- 1.5 million km away from earth- scans ~30% of the sky per day- full sky coverage after ½ year
![Page 6: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/6.jpg)
WMAP: Detectors I
![Page 7: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/7.jpg)
WMAP: Detectors II
-Two back to back symmetric telescopes
-Differential microwave radiometers
- Angle between opposite feed horns: ~ 141°
![Page 8: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/8.jpg)
Frequency Bands
K-band: ~22 GHz (13.6 mm) (1)Ka-band: ~30 GHz (10.0 mm) (1)Q-band: ~40 GHz (7.5 mm) (2)V-band: ~60 GHz (5.0 mm) (2)W-band: ~90 GHz (3.3 mm) (4)
![Page 9: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/9.jpg)
Thermal spectrum
K-band
W-band
![Page 10: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/10.jpg)
Cosmic Backgroundcharged particles interacting with magnetic fields
hot gas(thermal Bremsstrahlung)
thermalemission
![Page 11: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/11.jpg)
Map making
DT=T A −T B Measured signal
T 1 A =DT 1T B1T 2 A =DT 2T B2 ..T n A =DT nT Bn
T A =DTT B Absolute temperature
⟨T A ⟩=1n∑i=1
n
T i A
estimated
Iterative procedure
![Page 12: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/12.jpg)
Map projection
![Page 13: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/13.jpg)
Scan strategy
![Page 14: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/14.jpg)
Observation Map
![Page 15: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/15.jpg)
Galactic Plane Map
![Page 16: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/16.jpg)
Dipole Map
![Page 17: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/17.jpg)
K-band Map (23 GHz)
![Page 18: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/18.jpg)
Ka-band Map (33 GHz)
![Page 19: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/19.jpg)
Q-band Map (41 GHz)
![Page 20: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/20.jpg)
V-band Map (61 GHz)
![Page 21: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/21.jpg)
W-band Map (94 GHz)
![Page 22: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/22.jpg)
Final Map
![Page 23: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/23.jpg)
Comparison COBE-WMAP
53 GHz
94 GHz(30 times finer)
![Page 24: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/24.jpg)
Difference Map
![Page 25: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/25.jpg)
Spherical harmonics
![Page 26: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/26.jpg)
Power Spectrum I
T n =∑l∑m=−l
l
almY lm n
C Θ ≡⟨T n1⋅T n2 ⟩ n1⋅n2=cos Θ
∑m=−l
l
Y lm¿ n1⋅Y lm n2 =
2 l14π
P l n1⋅n2
C Θ = 14π∑l
al2 P l cos Θ al
2=∑m
∣alm∣2
![Page 27: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/27.jpg)
Power Spectrum II
C l=⟨∣alm∣2⟩m=
12 l1∑m
∣alm∣2= 1
2 l1al
2
C Θ = 14π∑l
2 l1 C l P l cos Θ
ΔT l=C l l l1 /2π
![Page 28: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/28.jpg)
Power Spectrum III
Θ~πl
![Page 29: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/29.jpg)
Primordial fluctuation region
Θ2°↔ lldec≈90
Angular scales larger than the causal horizon size at decouplingas observed today (primordial fluctuation spectrum)
![Page 30: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/30.jpg)
Acoustic Peak Region
2°>Θ0 . 2°↔90l900
This region can be described by the physics of a 3000 K plasmawith a number density of ne=300 cm-3 responding to fluctuation in the gravitational potential of dark matter (acoustic peak region)
![Page 31: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/31.jpg)
Silk Damping Tail
Θ0 . 2°↔ l900
The structure is produced by the diffusion of the photons fromthe potential fluctuations, and the washing out of the net observedfluctuations by the large number of cold and hot regions along the line of sight (Silk damping tail)
![Page 32: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/32.jpg)
Interpretation of the peaksInterpretation in terms of a flat adiabatic ΛCDM-cosmological-model
Only the position of the peaks and their ratios are considered
Physics of the acoustic peaks may be understood in terms of:
ωb ,ωm , ns , τ ,Θ A
mh2bh
2
ωm=ωbωc
baryondensity
matter density
angular scale of thesound horizon atdecouplingspectral
index
optical depth atreionization
![Page 33: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/33.jpg)
Peak ratios
For l>40 the peak ratios are insensitive to the intrinsic amplitudeof the power spectrum and τ due to:
Scattering of free electrons from reionization (z=20)with CMB photons -> lowering the fluctuation by nearly a constant factor
![Page 34: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/34.jpg)
The first acoustic peak- The peaks arise from adiabatic compression of the photon-baryon-fluid as it falls into preexisting wells in the gravitaional potential
- The potential wells are the result of some primordial field fluctuation (e.g. inflation field)
- The wells are enhanced by the dark matter (does not scatter off the baryons and photons)
- The first peak corresponds to the scale of the mode that has compressed once in the age of the universe (the photons decoupled from the electrons, t=379 kyr after Big Bang)
![Page 35: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/35.jpg)
Angular scale of the peaks
Θ A=r s zdec d A zdec
comoving size of the soundhorizon at decoupling
angular diameter distanceto the decoupling surface
![Page 36: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/36.jpg)
Geometric degeneracy
ωm , ωb Are well measured (affect the spectrum at early times)
Geometric degeneracy: Same A for different ωm , ωb
ωm=mh2
ωb=bh2
and h
It can be shown that A is the same for constant mh3 . 4
(assumption: flat geometry)
![Page 37: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/37.jpg)
Age of the Universe
b fixed to 0.023 (1region) (position of the first peak)
b fixed to 0.023 (2region) (position of the first peak)
1 limits on m
1 and 2 region of the full analysis
mh3 . 4=const ΘA
Seperation of m and h
isochrons
t0=6 .52h−1 1−m −1/ 2
ln 11−m
m [Gyr ]
![Page 38: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/38.jpg)
Basic Results
0.02
0.04
0.004
0.04
95% CL
0.002
1
0.04
0.2
8
+220 (-80)
1.02
0.73
0.044
0.27
<0.015
2.725
1089
0.71
13.7
379
180
tot
b
m
tcmb
zdec
h
t0
tdec
tr
Total density
Dark energy density
Baryon density
Matter density
Light neutrino density
CMB Temperature (K)
Redshift at decoupling
Hubble constant
Age of universe (Gyr)
Age at decoupling (kyr)
Age at reionization (Myr)
UncertaintyValueSymbolDescription
mν0 . 23 eV
Standard model of cosmology: flat -dominated universe seeded by a nearly scale-invariant adiabatic Gaussian fluctuation fits the data
![Page 39: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/39.jpg)
Future: Planck
- Start in the first quarter of 2007
- Frequencies from 30 GHz to 857 GHz
-Angular resolution: 5.0 arcmin to 33 arcmin (WMAP: 13.8 arcmin – 55.8 arcmin)
![Page 40: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/40.jpg)
References- The Cosmic Microwave Background Data and their Implications for Cosmology, V.Tudose, Romanian Reports in Physics, Volume 55, Number 2, P.116-142, 2003
- First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Preliminary Maps and Basic Results, C.L. Bennett et al. Astrophysical Journal
- Two-Point Correlations in the COBE DMR Four-Year Anisotropy Maps, G. Hinshaw et al. Astrophysical Journal, 464:L25-L28, 1996 June 10
- First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Interpretation of the TT and TE Angular Power Spectrum Peaks, L. Page et al. Astrophysical Journal
- WMAP-Homepage: http://map.gsfc.nasa.gov
- PLANCK-Homepage: http://www.rssd.esa.int/index.php?project=PLANCK
- First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: The Angular Power Spectrum, G. Hinshaw et al. Astrophysical Journal
- First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Determination of Cosmological Parameters
![Page 41: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/41.jpg)
Angular scale of the peaks II
r s zdec =3997 ωγ
ωmωb
ln1RdecRdecReq
1Req
R z =3 ρb z /4 ργ z
1zeq=5464 ωm /0 .135 T CMB /2.725 4 1 ρν / ργ
redshift at matter-radiation equality
![Page 42: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/42.jpg)
Angular scale of the peaks III
d A=∫0
zdec H 0−1dz
r 1z 4m 1z 3Λ
Λ=1−m−r
matter densitycurrent radiation density
angular diameter distance to the decoupling surface for a flat geometry
![Page 43: The cosmic background radiation II: The WMAP resultscrunch.ikp.physik.tu-darmstadt.de/nhc/pages/... · The cosmic background radiation II: The WMAP results Alexander Schmah 27.01.05.](https://reader033.fdocuments.net/reader033/viewer/2022060603/60585ad43ef7911ae12ba11e/html5/thumbnails/43.jpg)
Age of the Universe I
r s=147±2 Mpc
- First acoustic peak in the CBM power spectrum: known acoustic size:
at redshift: zdec=1089±1
Age: t0=13.7±0 . 2 Gyr
d A=14 .0−0 . 30 . 2 GpcDecoupling surface:
t0=6.52h−1 1−m −1/ 2
ln 11−m
m [Gyr ]