1. CMB physics
Zong-Kuan Guo
《现代宇宙学》

2. Outline §Background § CMB anisotropy theory § CMB experiments
Modern cosmology
Cosmic Microwave Background (CMB) radiation
§ CMB anisotropy theory
§ CMB experiments
§ Cosmological implications
Constraints on cosmological parameters
Some anomalies

3. § CMB experiments Ground-based experiments Balloon-borne experiments
Space-based experiments VS
Planck 2013
SPT

4. Ground-based experiments
Project
Location
Year
Status
l range
Frequency (GHz)
Polarization
ACBAR
Antarctic
Completed
150,219,274 No
CBI
Chile
26-36
VSA
Spain
SPT
2007-
Active
95,150,220
ACT
2008-
148,218,277
DASI
Yes
CAPMAP
USA
40,100
QUaD
100,150
BICEP
21-335
100,150,220
QUIET
40,90
BICEP2
150
KECKArray
2010-
ABS
2011-
25-200
145
POLARBEAR
2012-
90,150
SPTpol
95,150
ACTpol
2013-
90,146
BICEP3
2016-
Future -- 95
CLASS
40, 90, 150,220
𝑟~0.01

5. Balloon-borne experiments
Project
Location
Year
Status
l range
Frenquency (GHz)
Polarization
MAXIMA
USA
1995,98,99
Completed
50-700 No
BOOMERanG
Antarctic
90-420
Yes
EBEX
2012-
Active
150,250,410
SPIDER
2013,2015
10-300
90,150,280
PIPER --
2015-
Future
200,270,350,600
MAXIMA
BOOMERanG

6. Space-based experiments
Project
Funded by
Year
Status
l range
Frequency (GHz)
Polarization
COBE
NASA
Completed
2-40
31.5, 53, 90 No
WMAP
2-1200
23, 33, 41, 61, 94
Yes
Planck
ESA
2009-
Active
2-2500
30,44,70,100~857
CMBPol --
Future
COrE
LiteBIRD
JAXA
𝑟~0.001
COBE yr
WMAP yr
Planck yr
2006
NASA: CMBPol
ESA: COrE
JAXA: LiteBIRD

7. COBE (COsmic Background Explorer)

8. in thermal equilibrium
the first generation CMB experiment, launched on 18 Nov. 1989, 4 years
It carried three instruments:
Diffuse Infrared Background Experiment (DIRBE)
Differential Microwave Radiometer (DMR)
Far Infrared Absolute Spectrophotometer (FIRAS)
anisotropy
Hot big bang
in thermal equilibrium
J.C. Mather G.F. Smoot

9. the Nobel Prize in Physics 2006: J.C. Mather and G.F. Smoot
the COBE satellite experiments:
the Far InfraRed Absolute Spectrophotometer (FIRAS) team
the Differential Microwave Radiometer (DMR) team
advantages of satellite experiments:
no atmospheric thermal emission
full-sky map

10. WMAP (Wilkinson Microwave Anisotropy Probe)

11. the second generation CMB experiment, launched on 30 June 2001, 9 years
141°

12. free-free emission: electron-ion scattering
23 GHz
33 GHz
41 GHz
61 GHz
free-free emission: electron-ion scattering
synchrotron emission: the acceleration of cosmic ray electrons in magnetic fields
thermal emission from dust
94 GHz

13. foreground mask
angular power spectrum of CMB

14. WMAP science team publications
2003, WMAP1, 14 papers, arXiv:astro-ph/ has been cited by 7668 records.
2007, WMAP3, 5 papers
2009, WMAP5, 8 papers
2011, WMAP7, 6 papers
2012, WMAP9, 2 papers
2010 Shaw Prize, 2012 Gruber Prize
We have entered a new era of precision cosmology.

15. Planck

16. the third generation CMB experiment, launched on 14 May 2009, 30 months, 5 full-sky surveys
LFI
HFI
high sensitivity
wide frequency
full-sky coverage
high resolution ~5′ (15′, 7º)
LHC cost $8 billion;
Planck cost €700 million

17. Planck instrument characteristics
Planck instrument characteristics. The sensitivities (1σ) are goal values for 12 months integration and for square pixels whose sides are given in the row “Angular Resolution”. Polarisation measurement at 100 GHz on HFI is waiting for approval (the sensitivity level without polarisation measurement at 100 GHz is given in parenthesis).

21. Planck science team publications
2013, Planck 2013, 31 papers, arXiv: has been cited by 3796 records.
2015, Planck 2015, 28 papers, arXiv: has been cited by 588 records.
201x, Planck 201x, xx papers

22. 若把宇宙微波背景辐射比喻成一位美丽的少女，1964年的发现只是第一次听到了少女的声音，第一代探测卫星COBE已窥到了少女的身姿，而第二代探测卫星WMAP已揭开了少女的面纱，那么，欧洲航天局2009年5月发射的第三代探测卫星Planck已看到了少女的双眸。
——摘自《大百科物理学第三版》词条“宇宙微波背景辐射”

23. SPT (South Pole Telescope)

24. 3 frequencies (95, 150 and 220 GHz)
arXiv: : (360 citations) DR?
the effective number of neutrino species
arXiv: : (218 citations) Mass?
𝑁 eff =3.86±0.42
∑ 𝑚 𝜈 = 0.32±0.11 eV

25. ACT (Atacama Cosmology Telescope)

26. 3 frequencies (148, 218, and 277 GHz)

27. BICEP2 (Background Imaging of Cosmic Extragalactic Polarization)

28. BICEP1 ( )
BICEP2 ( )
BICEP3 ( )
BICEP Array ( )
SPT
The Dark Sector Lab (DSL)

29. 26 cm aperture
150 GHz
383.7 deg2
4 tiles
8×8 array of detector pairs
antenna networks
band-defining filters
bolometers

30. scan strategy

32. CMB data analysis

33.  the temperature anisotropies can be expanded in spherical harmonics
time-ordered data
full sky map
spectrum
parameter estimates
 time-ordered data
 the temperature anisotropies can be expanded in spherical harmonics
~ 10−5
map making
∆𝑇( 𝑛 ) 𝑇 = 𝑙𝑚 𝑎 𝑙𝑚 𝑌 𝑙𝑚 ( 𝑛 )
𝑑 𝑡 = 𝑃 𝑡𝑖 𝑚 𝑖 + 𝑛 𝑡
𝑎 𝑙𝑚 = 𝑑 𝑛 𝑌 𝑙𝑚 ∗ ( 𝑛 ) ∆𝑇( 𝑛 ) 𝑇
𝑡, elements; 𝑖, pixels
m = ( P 𝑇 N −1 P) −1 P 𝑇 N −1 d

34. Complete documentation of the package can be found at

35.  for Gaussian random fluctuations, the statistical properties of the
temperature field are determined by the angular power spectrum
𝑎 𝑙𝑚 ∗ 𝑎 𝑙 ′ 𝑚 ′ = 𝐶 𝑙 𝑇𝑇 𝛿 𝑙 𝑙 ′ 𝛿 𝑚 𝑚 ′
For a full sky, noiseless experiments,
𝐶 𝑙 𝑇𝑇 = 1 2𝑙+1 𝑚 𝑎 𝑙𝑚 2
 cosmological parameter estimation
likelihood function for a full sky:
−2 ln ℒ = 𝑙 (2𝑙+1) ln 𝐶 𝑙 th + 𝒩 𝑙 𝐶 𝑙 𝐶 𝑙 𝐶 𝑙 th + 𝒩 𝑙 −1
Planck Likelihood code is available at the website
Markov-Chain Monte-Carlo method

36. Metropolis algorithm. From arXiv:astro-ph/0311311

37. CosmoMC package is available at the website http://cosmologist

38. Thanks for your attention!