F.R. Bouchet- Cosmic Microwave Background: History, Status and Perspectives

8/3/2019 F.R. Bouchet- Cosmic Microwave Background: History, Status and Perspectives

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COSMIC MICROWAVEBACKGROUND

HISTORY, STATUS& PERSPECTIVES

F. R. BOUCHET

INSTITUT DASTROPHYSIQUE DE PARIS, CNRS

1965

1990

19992002 2008

1917

2020?

1943

1969

F.R. BOUCHET, IAP, CNRS, 27-28/11/07 GENERAL RELATIVITY TRIMESTER @ IHP 2

MENUCosmology has been covered by Silk & Uzan. See in particular Uzan forperturbation theory, which will be discussed in depth by MukhanovInflation & DM also, cf. StarobinskyI will therefore mostly focus on other aspects concerning the CMB

The CMB Introduction & Historical overviewSpectrumAnisotropies

WMAPPlanck & beyondTime permitting:

Secondary fluctuations (Gravitational effects & Thomson (re-) scattering)Component separation

Practical statistics (Estimating C(l), Higher order, E/B separation)Some useful web sites:

http://background.uchicago.edu/~whu (Wayne Hu)http://www.astro.ucla.edu/~wright/cosmolog.htm (Ned Wright)http://space.mit.edu/home/tegmark (Max Tegmark)http://cosmologist.info (Anthony Challinor)http://www.planck.fr (Planck/HFI Consortium site)


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CMB NUMERICAL DOMINATION (~93%)


STANDARD BB REMINDER 1/2

At early times, matter & radiation are in quasi-perfect thermalequilibrium > BB distributionIf deviations are created, then free-free interactions providethermalisation at all z > 3 x 10 7.Afterwards, the ff interaction time scale -1 becomes longerthan the expansion timescale H -1 : this process is frozen .Elastic (Thomson) scattering interaction has a mean free path = 8.3 H-1/[x e(1+z)]. As long as the plasma is ionized, xe =1 at z >1100, the universe is opaque.

At t


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z=1z=3z=20

z=1000

z: Big Bang z=1500

H Ato m protonelectron

photonOne of the 3 pillars of the standard model

z 80

CMB & LAST SCATERING SURFACE


STANDARD BB REMINDER 2/2

Expected temperature can be evaluated simply from basicphysics.Alpher, Beth, Gamow (48) showed that chemical elements could

have formed in the expanding BB, although forgetting thatradiation dominates over matter, which was corrected byGamow the same year & further corrected for a numericalerror by Alpher & Herman, who finally predicted T ~5K.Indeed, to get ~25% He, need to synthesize D first, which canonly happen at T ~109K, when the fusion can take place butwithout immediate photo-dissociation (1MeV ~1010K).Then H-1 ~200s, and substantial production (H -1 ~1/[nB pn>Dv] ,ie the Gamow condition) requires a baryon density n B~1018cm-3,to be compared to today, ~10 -7cm-3, which then fixes 1+z NS ~ 2x 108.Therefore T CMB= 109/(1+zNS) ~5K !


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F.R. BOUCHET, IAP, CNRS, 27-28/11/07 GENERAL RELATIVITY TRIMESTER @ IHP 8From a Ned Wright talk



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Penzias et Wilson antenna(Physics Nobel prize winners in 1978)

Cosmic Background predicted by Gamow in 1948 , and by Ralph Alpher & Robert Herman in 1950 . Serendipitously observed in 1965 par Arno Penzias and Robert Wilson at the Murray Hill Centre (NJ) of the Bell Telephone Laboratories as A source of excess noise in a radio Receiver . Joint interpretation article in Physical Review by Dicke, Peebles, Roll, Wilkinson(Princeton), contacted via Bernie Burke.


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A LONG MARCH ENSUESMany ground-based and mountain-top measurements filled in the0.3-20 cm wavelength range, giving T = 2.730.08 K.

Reworking and reobservingthe CN lines gave 2.780.10 K at 2.64mm. (Thaddeus, 1972, ARAA, 10, 305-334), 2.730.05 K (Oph)and 2.750.04 K (Per) by M.B. Kaiser & EL Wright (1990)Big excesses over blackbody seen or not seenby different rocket and balloon experiments.

2000 MJy/sr excess at 0.8 mm seenby Houck & Harwit(1969, ApJL, 157, L45)No excess seen by MIT group(Muehlner& Weiss 1972)Woody & Richards 2 mm excess in rocket(Phys. Rev. Lett. 42, 925 929 -1979)Berkeley-Nagoya rocket experiment(Matsumoto et al. 1988, ApJ, 329,567)with TB= 2.80 K at 1.1 mm; 2.96 Kat 0.7 mm & 3.18 K at 0.5 mm.


IN PARALLELOriginal COBE design was for a Deltarocket

COBE was directed to use the shuttle andthe design was actually nearly completedin Jan 1986.

Then the Challenger blew up on launchSo back to a Delta

The shuttle version of COBE weighed5,000 kg and also needed a 700 kg vacuumpump in the shuttle bay.It was the full shuttle payload fromVandenberg AFB. A > 500 M$ launch.Redesigned to fit on a Delta implied

The mass went down to 2300 kg.The launch cost went down to about 30M$.No science was lost, but the scheduletook a 2 year hit.


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EARLY FIRAS RESULTS


FINAL SPECTRUM

400 : les barres derreurs ont tmultiplies par 400 pour les rendre

visibles par rapport lpaisseurdu trait montrant un corps noir

parfait 2,728K


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TIGHT CONTRAINTS RESULTCompton scatterings of by hot edepletes low E (Rayleigh-Jeans, h/kT 105, y > 1 (in standard BB), theplasma can reach statistical equilibrium.But when z < 107, there is no photonproduction, therefore nothermodynamical equilibrium; leads to aBose-Einstein spectrum characterisedby a chemical potential Very late energy release, at z


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Chaquepoint estune galaxiecomme laNotre. Laplus proche,M31, est ~2,5 Mal.Il faut 2,7milliardsdannes la lumiredunegalaxie surle cercle

vert pourquelle nousparvienne.

LE MONDE LOINTAIN DES GALAXIES!

NOUS


Inflation ?t = 10-32 sT = 1016 GeV

Surface des derniresdiffusions ( sur e)t = 370 000 ansT = 0,3 eV = 3000 K

Grandes structuresdu voisinage t=13,7 GansT=2,725 K


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F . R

. B o u c h e t , C

C P P @

N Y U

, 2 0 0 4 / 0 5 / 1 7

F . R

. B o u c h e t , C

C P P @

N Y U

, 2 0 0 4 / 0 5 / 1 7

t

t

k

Given initial conditions (type & statistics,e.g. Adiabatic fluctuations only, Gaussianwith P(k) = A k n), and an energy census of the Universe (cosmological parameters, ),one can compute the temporal evolution of each and every (linear) mode and obtain

the evolved matter power spectrum,or its transfer function at LSS (dependingmostly on sound speed history at M < M J).

Idem for the radiation Transfer Function .


Initial CMBCalculations

Matter calculations

PRECISION COSMOLOGY

First numerical CMB calculation (to go through recombination)

1965+5


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CDM & scale-invariant initial conditions in some detail:ApJ, 1984, L45-48 & L 39-43 (Inflation is 1982)


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1987: Detailed Statistics



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SINCE THENAngular power spectra C(l) became the norm

T(n) = lm alm Ylm(n) ; alm = d T Y*lm

=llmmC(l) (If statistical isotropy) = Cpp= (2l+1)/4pi C(l) Pl(np, np)\hat C(l) =1/(2l+1) m |a lm| 2

K 0 calculationsElegant reformulations, introduce E & B to representpolarisation, many gauges (or absence of)Precision of predictions increased ( < 1 %)Speed also (tremendously).Off the shelf codes: CMBFAST [Seljack & Zaldarriaga 96],CAMB [Lewis et al. 2000] & CMBSLOW [Riazuelo],CMBEASY, etc

With further options, e.g. lensing correction, isocurvaturemodes, reionisation (still ongoing)Detailed degeneracy studies


OSCILLATIONS ACOUSTIQUES

MJ

Echelledu degr

M > M J non affectes

M < M J oscille

temps SDD


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OSCILLATIONS ACOUSTIQUES

temps

MJM > M J non affectes

M < M J oscille

Echelle de

~ 1 degr

SDD


Sachs-Wolfe

Doppler SW Intgr(ISW=transit travers GSU)

SilkDamping

COSMOMTRIE : SPECTRE DE PUISSANCE ANGULAIRE

DES ANISOTROPIES DE TEMPRATURE

Hauteurdes vagues/ longueurdonde l

NB1 : Ici, cas restreintde fluctuationsScalairesuniquement(sinon il existe un termeadditionnel)NB2 : SW & ISW sontanti-corrls

( 1/ ) Fig. Riazuelo


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RECAPWe can (maybe) compute properties of Initial conditions, or at least parametrizethem > As, ns, At, ntPerturbation theory

Linear regime (As ~10-5

) > can conveniently analyse Fourier modes independentlyWell understood physicsThomson elastic scatterings, coupling of electron and photonsRecombination (simplest = Saha equilibrium)General relativity, in linear regimeStatistical mechanics Boltzmann eq. for angular distribution of photons

Few scales involvedSound wave travel distance ~c st- determines when starts to oscillate (pressure support)Diffusion damping length Ndiff 1/2..- determines smallest surviving fluctuations (in baryons-photon fluids)Time from big bang to last scattering (~300Mpc comoving; ~300 000 years) determines physical size of largest overdensity (or underdensity)Distance of last scattering from us (~14Gpc comoving; 14 Gyr)- determines angular size seen by usThickness of last scattering (~Hubble time, 100Mpc)- determines line of sight averaging- determines amount of polarization (later)

Interplay of several related effects allows rich phenomenology > opportunities

Intrinsic (compressed photons > hotter)SW (redshift to clim out of potential wells at LSDoppler (from oscillating e b fluid)ISW (from evolving potential on los Om .NE.1)+ smaller (second order effects) lensing, SZ, etc


INITIAL CONDITIONS DEPENDENCE

FomT

m

kswbst

NB: there is now a fairnumber of off-the-shellcodes with variousadvantages:-CMBFAST > cmbfast.org-CAMB > camb.info-CMBEASY > cmbeasy.org-CMBSLOW-COSMICS


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POWER SPECTRUM SHAPE ANDCOSMOLOGICAL PARAMETERS


CENSUS

Baryons Darkmatter

NeutrinoFraction w in p=w


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CMB IS A RICH INFORMATION MINE

Initial conditionsWhat types of perturbations, power spectra, distribution function (Gaussian?); => learn aboutinflation or alternatives.(distribution of T; power as function of scale; polarization and correlation)

What and how much stuffMatter densities ( b, cdm);; neutrino mass(details of peak shapes, amount of small scale damping)

Geometry and topologyglobal curvature K of universe; topology(angular size of perturbations; repeated patterns in the sky)

EvolutionExpansion rate as function of time; reionization- Hubble constant H 0 ; dark energy evolution w = pressure/density(angular size of perturbations; l < 50 large scale power; polarizationr)

AstrophysicsS-Z effect (clusters), foregrounds, etc.


+= m lmobs

l alC 2||

121

)|( obsll C C P

122

||2

2

+

lC

C lobsl

Cosmic Variance

Use estimator for variance:

- inverse gamma distribution(+ noise, sky cut, etc).

WMAP low l

l

d.o.f.12with~ 2 +lC obsl

Cosmic variance gives fundamental limit on how much we can learn from CMB

Assume a lm gaussian:

COSMIC VARIANCE: ONLY ONE SKY

From Challinor


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GEOMETRICAL DEGENERACYAngular diameter distance controls the mapping from k to lModels with same R (and IC & matter content - b & c)

Have very similar spectra, but at Low l (SW)

Constant R lines

values

Efstathiou & Bond 1999


FISHER MATRIX GUIDELINESMicrowave sky = primary + secondary + foregroundsMeasured sky = Microwave sky + random errors +systematic errors.Theory T i = f ( p, ,IC j)Constraining theory with data : P(T|D) L(D|T) P(T)Fisher matrix, , encodes the power of the dataAssume we succeed in isolating only primary fluctuationsand noise..

Quantifies the (remaining) obstacles ( i>= F

ii

-1/2):Degeneracies within the pDegeneracies within the IC, and IC vs. pCosmic variance (one sky), noise (i.e. sensitivity), resolution

F ij = T j T i 2 ln L

F ij = Xl

2(2l + 1) f sky[C l + C N exp 2b(l

2)] 2 T j

C l T j

C l


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Carte diffrence ( chelles < 1 deg):Oscillations acoustiques aux petites chelles< ct quand t=370 000 ans (~150Mpc aujourdhui).Permet de recenser le contenu

Carte lisse (suppression des chelles < 1 deg) :Fluctuations Quantiques imprimes

quand lage de lUnivers tait danslintervalle [10 -43 , 10 -12 ] seconds

Plan Galactique

CE QUON VEUT OBSERVER

PAUSEAPRES

1H+15MN


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TERRATERRA

INCOGNITA INCOGNITA

1992 state


DMR (DIFFERENTIALMICROWAVERADIOMTERS)


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By 1994,Scott & WhiteGive 95% CLthat Doppler Peak ispresent9407073

NB: 1996 is the year of the

selection- by NASA of WMAP (againstFIRE & PSI) and-by ESA of COBRAS/SAMBAas M3 of Horizon 2000+(to become Planck)


LATE 1999 STATE


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F.R. BOUCHET, IAP, CNRS, 27-28/11/07 GENERAL RELATIVITY TRIMESTER @ IHP 60 Bouchet et al. 2000

Bouchet & Bennett 1988


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VSA , may 2002

Compares well with BOOM, MAXIMA, DASI

VSA III, Scott et al. astroph/0205380SA III, Scott et al. astroph/0205380

F.R. BOUCHET, IAP, CNRS, 27-28/11/07 GENERAL RELATIVITY TRIMESTER @ IHP 65SASA -IV,V, Rubinoubino-Martin et al. astroph/0205367artin et al. astroph/0205367

And appears quantitativelyquantitatively consistent with BOOM, MAX & DASI

(All using DMR + similar prior)


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CBI(also May 2002)

Mason et al. astroph/0205384ason et al. astroph/0205384


2 contoursFor DMR

+CBI

BOOMDASI

MAXIMAPREVIOUS( Boom NA+ TOCO +

17 < Apr 99)and

ALL (filled)(& inner 1 )

Left panelsadditionallyinclude an LSS prior (constrainton 8 & eff )

NB: all panelsmade for the weak-h prior (i.e. 0.45 0.1) ns & b panelsadd k =0 hatched regionsnot searched

Sieversieverset al. astroph/0205387t al. astroph/0205387


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France

Italy

U.K.

U.S.A.

CESR, CRTBT, CSNSM, IAP, IAS,ISN, LAL, LAOG, PCC/CdF, OMP, SPP/CEA

Univ. La Sapienza (Rome), IROE CNR

QMW (London Cardiff)

CALTECH, JPL, Univ. Of Minnesota

RussiaLandau Ins. of Theoretical Physics

http://www.archeops.org

P.I. A. Benoit (CRTBT)

THE ARCHEOPSCOLLABORATION

F . R . B o u c h e t , C

C P P @

N Y U

, 2 0 0 4 / 0 5 / 1 7

F . R . B o u c h e t , C

C P P @

N Y U

, 2 0 0 4 / 0 5 / 1 7

CAPP2003, JUNE 11TH 2003 F. R. BOUCHET, IAP, ON BEHALF OF THE ARCHEOPS COLLABORATION 69

Archeops Maps First submillimetric maps at 15 arcmin resolution, 30% skyPointing reconstruction with stellar sensor ( rm s < 1.2 arcmin)

545 GHz0.55 mm

353 GHz0.85 mmPolarized

143 GHz2.1 mm

217 GHz1.4 mm

217 GHz217 GHz

143 GHz143 GHz

Lin-Log Scale


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END OF 2002 STATUS

Octobre 2002

Benoit et al 2003, A & A, 399, L25


THOMSONSCATTERINGS

ARE POLARISED


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POLARISATION

Before recombination, successive scatterings destroy polarization and theradiation arrives at recombination unpolarizedDuring recombination, Gradients in the velocity field can produce a quadrupole inthe rest frame of the scattering electron

Fig. de Bernardis


POLARISATION



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POLARISATION



POLARISATION



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Tensorial perturbations, i.e. gravity waves, also producequadrupole anisotropies. A (faint) stochastic background of

such waves is a generic feature of inflation models.

This component of a CMB polarisation field is called byanalogy the B (or curl) componentVelocity fields (Curl-less) cannot produce B-modes.

Weak Lensing by foreground Large Scale structures afterrecombination can, but with a predictable amplitude from TT Any full sky (polar) map can be decomposed in E & B modes

POLARISATION


From observations, one usually deduces the StokesParameters Q and U (assuming no circular polarization V)This description is not invariant under rotation of thecoordinate system:

But the description in terms of the scalar and pseudo-scalarfields E and B is rotationally invariant

Four independent power spectra can be measured, the othersbeing zero by symmetry:

CTT , CTE, CEE, CBB

POLARISATION


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3 observables : T, E, B

Les modes Bne peuventpas tre gnrs pardes fluctuationsprimordiales scalaires

SPECTRES DE PUISSANCE DU RCF

( 1/ )

E < 0 E > 0

B < 0 B > 0

E < 0 E > 0

B < 0B < 0 B > 0


MOTIFS POLARISS ATTENDUS

w w w . a s

t r o . c a

l t e c h . e d u / ~ l g g

/ b i c e p_

f r o n t . h

t m

T ~ 100 K, E ~ 4 K B ~ 0.3 K

T/S - 0.28

E < 0 E > 0

B < 0 B > 0

E < 0 E > 0

B < 0B < 0 B > 0


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T E

T+ E+ B+

LENTILLAGE DU CMB

Les grandes structures transforment du E en B


3 observables : T, E, B

Les modes Bne peuventpas tre gnrs pardes fluctuationsprimordiales scalairesmais lentillage par lesgrandes structurestransforme du E en B

SPECTRES DE PUISSANCE DU RCF

( 1/ )

~5K.arcmin

E < 0 E > 0

B < 0 B > 0

E < 0 E > 0

B < 0B < 0 B > 0


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Fom

FomT

m

ks

T

m

kswbst

wbst

B

f

M


WHAT CAN WE LEARN FROM POLARISATION?

Consistency check of the paradigm (may also include evolution or lack of- of physical constants)Check whether there are super-horizon perturbationsImprovement in parameter constraints (lifting degeneracies, eg,ns vs tau) and on features in the primordial spectrumIsocurvature perturbations (see later)

Reionization historyHelp with lensing reconstruction of los-projected matterdensity properties (P kk)

Gravitation wave from inflation existence, maybe n T (and indirectly on inflaton potential)


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F.R. BOUCHET, IAP, CNRS, 27-28/11/07 GENERAL RELATIVITY TRIMESTER @ IHP 89Window functions for E & B

Acceptable modelsfrom T analysis

5 away from (0,0) in E,B plane

WindowX model

DASI BANDPOWER ANALYSIS

2002


END OF 2002 POLARISATION KNOWLEDGE


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F . R

. B o u c h e t

@ C

D F , 2 0 0 4 / 0 6 / 0 8

F . R

. B o u c h e t

@ C

D F , 2 0 0 4 / 0 6 / 0 8

Concordancemodel: LCDM

F . R

. B o u c h e t

@ C

D F , 2 0 0 4 / 0 6 / 0 8

F . R

. B o u c h e t

@ C

D F , 2 0 0 4 / 0 6 / 0 8

C (` ) = R + W (k)P ?(k)d ln k

kW (k)


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F . R

. B o u c h e t

@ C

D F , 2 0 0 4 / 0 6 / 0 8

F . R

. B o u c h e t

@ C

D F , 2 0 0 4 / 0 6 / 0 8

Tegmark & Zaldarriaga, astroph/0207047

h 2 m = 0 .12, h2 b = 0 .021, = 0 .71, h = 0 .7, = 0 .05 ( zr = 8) , 8 = 0 .815

values plotted at P ?id / P (k, z) = P ?(k) T 2(k, z)k P ?id = R

+ W i(k) d ln k

di

USING THE CONCORDANCE MODEL PARAMETERS

F . R

. B o u c h e t

@ C

D F , 2 0 0 4 / 0 6 / 0 8

F . R

. B o u c h e t

@ C

D F , 2 0 0 4 / 0 6 / 0 8

Wrong b

T e g m a r

k & Z a l d a r r i a g a , a s t r o p

h / 0 2 0 7 0 4 7


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NOW, LETSTURN TO WMAP

RESULTS

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F.R. Bouchet- Cosmic Microwave Background: History, Status and Perspectives

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