a brief history of the cmb

April 2, 2015 Ganga/CMB & Planck 2

A Brief History of the CMBPenzias & Wilson

discovered it.

COBE Measured it.

WMAP Used it.

Planck Refines it.

April 1, 2015/Ganga Cosmological Parameters 3

Visualize the Evolution of the Universe

The microwave background light we see today was

created “just after” the Big Bang (~380k yr)

As such, it is a “baby picture” of the early Universe. By studying it, we hope to understand it's birth.

http://map.gsfc.nasa.gov/media/060915/index.html


Many Different Effects Together

TT

EE

BB

Lensing GWB

max compressionmax rarefaction

photondiffusion

scale

reionization: peaklocation ~ (SLS horizon) x

sqrt(z_reion / z_rec) ~ 10

inflationpotential

curvature,acoustic horizon

baryon density

damping from photondiffusion, sensitive to

matter density

SLS thickness (~ 860)

Sachs-Wolfe effect

SLS horizonscale (~ 100)

oscillations out of phase:TT ~ density extrema,EE ~ velocity extremaoscillationfrequencydiffers by factorof sqrt(3): sound vs. light speed

gravitational waveson small scales decay away(amplitude ~ 1/a)

ratio of quadrupolemoment power = T/S( = 0.05 in this plot)

Cynthia Chiang


IntroductionPrecursors COBRAS

and SAMBA

conceived in 1993.

Selected in 1996, with inputs from

failed WMAP

competitors FIRE and

PSIhttp://www.cosmos.esa.int/documents/387566/387653/Ferrara_Dec1_09h50_Bersanelli_Planck_mission.pdf


IntroductionHFI

became polarization sensitive in

2001 (~when

WMAP was launched).

Planck was launched 14 May

2009. (~13 years from selection to

launch.)http://www.cosmos.esa.int/documents/387566/387653/Ferrara_Dec1_09h50_Bersanelli_Planck_mission.pdf


LaunchPlanck was launched May 14, 2009 aboard an

Ariane 5 along with the Herschel Space Observatory, which is also orbiting around L2.


Voyage and OrbitPlanck traveled the 1.5 million

kilometers to the second Sun-

Earth Lagrange point in about three months


Planck's Orbit around L2Planck orbits around the

second Sun-Earth Lagrange point, about 1.5 million kmfurther from the Sun than

the Earth

A diagram from Wikipedia showing the Sun–Earth L2 point, which lies

well beyond the Moon's orbit around the Earth


Planck's Scanning Strategy

Planck scans the sky in (almost)

great circles in a plane defined by the Sun-

Earth axis. The full sky is (almost) covered each six months.


Frequency/wavelength coveragePlanck fills

the SubMM

range, so in addition

to CMB science,

Planck will be able to say a lot

about dust emission

in our Galaxy and in

others.



the SubMM


to CMB science,


about dust emission


others.


Planck MapsPlanck has twoinstruments:

- LFI:-- 30,-- 44,-- 70 GHz

- HFI-- 100,-- 143,-- 217,-- 353,-- 545,-- 857 GHz


Asteroids and Zodiacal Emission


The CMB and Galactic Dust


Vibrational & Spinning Galactic Dust


Polarized Foregrounds


Galactic Synchrotron & Free-Free


Galactic Carbon Monoxide & Spectra

arXiv:1303.5088v1This has been updated with the “PCCS2”

We often treat these emissions as annoyances, but many people find them

quite interesting!


2013 Temperature Power Spectrum


2014 Temperature Power Spectrum


Power Spectra and Parameters● H0 = 67.8 ± 0.9 kms-1Mpc-1

● Ωm = 0.308 ± 0.012

● ns = 0.968 ± 0.006● τ = 0.066 ± 0.016● Neff= 3.15 ± 0.23

● Σmν < 0.23 eV

● This spectrum can be reconstructed using only six parameters – Amplitude, simple spectrum of “input” variations, baryonic & cold

dark matters, oscillation scale & optical depth (+Λ)– This simple agreement extends to polarization as well– There is no convincing evidence for extensions to the standard

model of cosmology


Non-Gaussianity● We do find the ISW

bispectrum expected in a CDM Universe

● We do see non-Gaussianity from point sources

● We don't see any– Local: 0.8 ± 5.0– Equilateral: -4 ± 43– Orthogonal: -26 ± 21– (68%CL)

http://arxiv.org/abs/1502.01592


Gravitational Lensing● Mass between the last

scattering surface and us lenses the CMB

● We use the deflections to infer the effective potential seen by the CMB



Cosmic Infrared Background

● Dominates the extragalactic sky in the higher Planck frequencies

● Has a spectrum similar to Galactic dust● Tracer of star formation, much of it around z~2.● Represents material at higher redshifts than many catalogs● arXiv:1309.0382v1


CIB × Lensing Potential● The CIB is the remnant of

star formation, much around z~2

● This material lenses the CMB● A cross-correlation shows

this:

● Correlations can also be done with your favorite catalog of sources, or other tracers of mass

ArXiv: 1303.5078v1

545 GHz × Φ


SZ Catalog

Sunyaev-Zeldovich Effect● Hot electrons in

clusters give CMB photons “a kick”

● This allows us to detect 1653 clusters and candidates of clusters of galaxies

http://spiff.rit.edu/classes/phys443/lectures/cluster_2/sunyaev.png -- Michael Richmond


Spectra Zoo

r = 0.2

Scalar TT

Tensor TT

Scalar TE

TensorTE

ScalarEE

TensorEE

Tensor BB

Lens BB

Scalar & Tensor TT, TE, EE & BB Spectra

Reionization changes the

amplitude of the anisotropies

and adds signal at the largest

angular scales


Optical Depth from Large Ang. Scales

http://webcast.in2p3.fr/videos-establishing_the_planck_only_likelihood

5 10 15 20 25

70 GHz DataPlanck 2013 (τ~0.9)Planck 2015 (τ~0.7)

LFI Noise Level


ReionizationLFI polarization data, together with Planck lensing and high-multipole temperature data gives a reionization optical depth, τ=0.066±0.016 and a reionization redshift of zre=8.8+1.7

-1.4. These numbers are in good agreement with those inferred from the WMAP9 polarization data cleaned for polarized dust emission using the HFI 353 GHz maps, as well as Planck temperature and lensing data (i.e., not using polarization data).

Early WMAP was here


CMB: Primordial vs. Recent● The CMB has

traditionally be used to probe the early Universe– First to understand the

Universe at t > 400k years and the total energy density of the Universe

– Now to try to understand what led to our Universe (i.e., is Inflation correct, or is it something else?)

● The CMB is being used more and more as a tool to understand what is between us and the surface of last scattering– SZ effect and clusters– SZ and baryons– Lensing and Galaxy

formation– Lensing and neutrinos


Relic Gravitational Waves – B-Modes

http://bicepkeck.org/visuals.html


Polarization of the CMB


Spectra Zoo & B-Modes

r = 0.2

Scalar TT

Tensor TT

Scalar TE

TensorTE

ScalarEE

TensorEE

Tensor BB

Lens BB

Dorothea Samtleben will discuss this as well

'r' quantifies

the fraction of power in

tensors versus scalars


Inflation● ns = 0.968 ± 0.006● Tensor-to-scalar ratio: r < 0.11 (95% C.L.)● Further measurements of B-mode polarization will

improve limits on “r”

arXiv:1502.02114n

s →

r


BICEP Sees r ~ 0.2

● “The observed B-mode power spectrum is well-fit by a lensed-LCDM + tensor theoretical model with tensor/scalar ratio r=0.20+0.07

-

0.05.” -- BICEP2 I: Detection of B-mode Polarization at Degree Angular Scales (2014)

● We were looking for a needle in a haystack, but instead we found a crowbar. -- Clem Pryke

● “... the fractional contribution of tensor modes is limited to r < 0.13 (95% CL)” -- Nine-year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Parameter Results (2012)

● “Planck establishes an upper bound on the tensor-to-scalar ratio of r < 0.11 (95% CL).” -- Planck 2013 results. XXII. Constraints on inflation.


Spectral Subtraction Analysis● We also try a simple

analysis, subtracting the scaled 150x353 spectrum from the 150x150 spectrum– This approximates a map-

based cleaning● The resulting r constraint is

similar (although a little less powerful than that from the “full” analysis)

● r<0.12 from BICEP+Planckhttp://adsabs.harvard.edu/abs/2015arXiv150202114P


Fig. 8: Best Parts of the Polarized Sky● Value of BB spectrum at ℓ=80, normalized to a spectrum with r=1. – Deep red is r~10– Orange/red is r~1– Blue/cyan is r~0.1– Deep blue is r~0.01

● Computed from the 353 GHz data and extrapo-lated to 150 GHz using power law above

Signal

Uncertainty


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Planck Release Schedules● What has been released:

–

–

● High-ℓ Likelihood: CMB+Lensing, Temperature+Polarization – Low-l: Based on LFI 70 GHz (replacing WMAP)

● Lensing● SZ, point sources, ...● Galactic Emissions● ...


Acknowledgements

a brief history of the cmb

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