CAPMAPCAPMAPCAPMAPCAPMAP
Measuring the Measuring the Polarization of thePolarization of the
CCosmic osmic
MMicrowave icrowave
BBackgroundackground
Measuring the Measuring the Polarization of thePolarization of the
CCosmic osmic
MMicrowave icrowave
BBackgroundackground
Dorothea Samtleben, Center for Cosmological Physics,University of Chicago
Center for Cosmological Physics Center for Cosmological Physics (CfCP)(CfCP)
Center for Cosmological Physics Center for Cosmological Physics (CfCP)(CfCP)
National Science Frontier CenterNational Science Frontier Center
Founded at the University of Chicago in August Founded at the University of Chicago in August 2001 for initially 5 years2001 for initially 5 years
Creation of an interdisciplinary environmentCreation of an interdisciplinary environment
14 faculty, 10 center fellows, 14 faculty, 10 center fellows, graduate students, associated graduate students, associated postdocs ...postdocs ...
National Science Frontier CenterNational Science Frontier Center
Founded at the University of Chicago in August Founded at the University of Chicago in August 2001 for initially 5 years2001 for initially 5 years
Creation of an interdisciplinary environmentCreation of an interdisciplinary environment
14 faculty, 10 center fellows, 14 faculty, 10 center fellows, graduate students, associated graduate students, associated postdocs ...postdocs ...
Research FocusResearch FocusResearch FocusResearch Focus
TheoryTheory
Structures in the UniverseStructures in the Universe
Cosmic Radiation BackgroundsCosmic Radiation Backgrounds
High Energy Particles from SpaceHigh Energy Particles from Space
TheoryTheory
Structures in the UniverseStructures in the Universe
Cosmic Radiation BackgroundsCosmic Radiation Backgrounds
High Energy Particles from SpaceHigh Energy Particles from Space
Four major research components:Four major research components:
Activities of the CenterActivities of the CenterActivities of the CenterActivities of the Center
Various formal and informal seminarsVarious formal and informal seminars
Workshops (Auger-workshop, COSMO-02)Workshops (Auger-workshop, COSMO-02)
VisitorsVisitors
Dedicated outreach and education effortsDedicated outreach and education efforts
Opportunities for sabbaticals for High Energy Opportunities for sabbaticals for High Energy Physicists Physicists
Various formal and informal seminarsVarious formal and informal seminars
Workshops (Auger-workshop, COSMO-02)Workshops (Auger-workshop, COSMO-02)
VisitorsVisitors
Dedicated outreach and education effortsDedicated outreach and education efforts
Opportunities for sabbaticals for High Energy Opportunities for sabbaticals for High Energy Physicists Physicists
Motivation What do we want to learn from our experiment?
Experimental approach Which strategy to choose?
Experimental design What does our experiment look like?
Motivation What do we want to learn from our experiment?
Experimental approach Which strategy to choose?
Experimental design What does our experiment look like?
Talk Outline Talk Outline
How can we improve our How can we improve our understanding of nature?understanding of nature?How can we improve our How can we improve our understanding of nature?understanding of nature?
Set up an experiment to study a well defined Set up an experiment to study a well defined configurationconfiguration e.g. High Energy Physicse.g. High Energy Physics
Study the outcome of an experiment which nature Study the outcome of an experiment which nature has set up has set up e.g. Astrophysicse.g. Astrophysics
Set up an experiment to study a well defined Set up an experiment to study a well defined configurationconfiguration e.g. High Energy Physicse.g. High Energy Physics
Study the outcome of an experiment which nature Study the outcome of an experiment which nature has set up has set up e.g. Astrophysicse.g. Astrophysics
Setup of nature‘s ‘experiment‘Setup of nature‘s ‘experiment‘
How can we find out what happened How can we find out what happened in the early universe?in the early universe?How can we find out what happened How can we find out what happened in the early universe?in the early universe?
We do have witnesses!We do have witnesses!
We will learn about the conditions in the infant We will learn about the conditions in the infant universe by a thorough questioning of the universe by a thorough questioning of the witnesses witnesses
We can compare our theories with the We can compare our theories with the information they provide and improve our information they provide and improve our understanding of the evolution of the universeunderstanding of the evolution of the universe
We do have witnesses!We do have witnesses!
We will learn about the conditions in the infant We will learn about the conditions in the infant universe by a thorough questioning of the universe by a thorough questioning of the witnesses witnesses
We can compare our theories with the We can compare our theories with the information they provide and improve our information they provide and improve our understanding of the evolution of the universeunderstanding of the evolution of the universe
The witnesses: Photons of the Cosmic Microwave Background Radiation
The witnesses: Photons of the Cosmic Microwave Background Radiation
-100 K +100 K
The sky observed at 90 GHz (COBE DMR)The sky observed at 90 GHz (COBE DMR)
What happened 300,000 years What happened 300,000 years after the Big Bang?after the Big Bang?What happened 300,000 years What happened 300,000 years after the Big Bang?after the Big Bang?
The plasma of photons, protons and The plasma of photons, protons and electrons became cold enough so that electrons became cold enough so that electrons and protons formed first atomselectrons and protons formed first atoms
The universe became transparentThe universe became transparent
These photons give us a direct snapshot of These photons give us a direct snapshot of the infant universethe infant universe
Still around today but cooled down (shifted Still around today but cooled down (shifted to microwaves) due to the expansion of the to microwaves) due to the expansion of the universeuniverse
The plasma of photons, protons and The plasma of photons, protons and electrons became cold enough so that electrons became cold enough so that electrons and protons formed first atomselectrons and protons formed first atoms
The universe became transparentThe universe became transparent
These photons give us a direct snapshot of These photons give us a direct snapshot of the infant universethe infant universe
Still around today but cooled down (shifted Still around today but cooled down (shifted to microwaves) due to the expansion of the to microwaves) due to the expansion of the universeuniverse
Expectations from inflationary models Expectations from inflationary models for CMB observationsfor CMB observationsExpectations from inflationary models Expectations from inflationary models for CMB observationsfor CMB observations
Blackbody spectrumBlackbody spectrum
Homogeneous, isotropicHomogeneous, isotropic
On large scales scale-invariant temperature On large scales scale-invariant temperature fluctuations (regions were not yet causally connected)fluctuations (regions were not yet causally connected)
On small scales temperature fluctuations from On small scales temperature fluctuations from ‘accoustic oscillations‘ (radiation pressure vs ‘accoustic oscillations‘ (radiation pressure vs gravitational attraction)gravitational attraction)
Polarization anisotropies, Polarization anisotropies, correlated with temperature anisotropiescorrelated with temperature anisotropies
Blackbody spectrumBlackbody spectrum
Homogeneous, isotropicHomogeneous, isotropic
On large scales scale-invariant temperature On large scales scale-invariant temperature fluctuations (regions were not yet causally connected)fluctuations (regions were not yet causally connected)
On small scales temperature fluctuations from On small scales temperature fluctuations from ‘accoustic oscillations‘ (radiation pressure vs ‘accoustic oscillations‘ (radiation pressure vs gravitational attraction)gravitational attraction)
Polarization anisotropies, Polarization anisotropies, correlated with temperature anisotropiescorrelated with temperature anisotropies
Characteristics of the CMBCharacteristics of the CMBCharacteristics of the CMBCharacteristics of the CMB
Frequency Frequency SpectrumSpectrum
Temperature Temperature AnisotropyAnisotropy
PolarizationPolarization
Frequency Frequency SpectrumSpectrum
Temperature Temperature AnisotropyAnisotropy
PolarizationPolarization
Frequency spectrum of the CMB (Compilation by Richard McCray)
Frequency spectrum of the CMB (Compilation by Richard McCray)
Temperature Anisotropy of the CMBTemperature Anisotropy of the CMB
Dipole due to peculiar velocity of solar system
Emission from the galactic plane
Remaining CMB anisotropy
Dipole due to peculiar velocity of solar system
Emission from the galactic plane
Remaining CMB anisotropy
COBE results
DASI: First Detection of CMB Polarization (September 2002)
DASI: First Detection of CMB Polarization (September 2002)
Map is 5 degrees square
200 K
100
0
-100
- 200 K
5 K
Spherical Spherical HarmonicHarmonicss
Spherical Spherical HarmonicHarmonicss
Description of Description of CMB by using CMB by using spherical spherical
harmonicsharmonics YYlmlm))
Description of Description of CMB by using CMB by using spherical spherical
harmonicsharmonics YYlmlm))
),(),(,2
ϕθϕθ lmml
lmYaT ∑≥
=
Ylm
Pictures by Clem Pryke
Description of AnisotropiesDescription of AnisotropiesDescription of AnisotropiesDescription of Anisotropies
>=<+
=Δ *2
2
)1(lmlmll aaCC
llT
π Usually representation by power
spectrum Cl (variance at the multipole l)
Angular scale: ~ 180°/l
Usually representation by power spectrum Cl (variance at the multipole l)
Angular scale: ~ 180°/l
),(),(,2
ϕθϕθ lmml
lmYaT ∑≥
=
Statistical properties of CMB can be observed and compared with theory
Statistical properties of CMB can be observed and compared with theory
Temperature Power SpectraTemperature Power SpectraTemperature Power SpectraTemperature Power Spectra
Compilation by Wayne Hu
Compilation by Max Tegmark
Dependence on cosmological Dependence on cosmological parametersparametersDependence on cosmological Dependence on cosmological parametersparameters
Change in baryon densityChange in baryon density
Change in curvatureChange in curvature
Animations by Max Tegmark
Why is the CMB polarized?Why is the CMB polarized?Why is the CMB polarized?Why is the CMB polarized?
Thomson scatteringThomson scattering
Radiation incident along this axis
Charge moves along this axis
Radiation primarily scattered along this axis
Charge moves in two directions
Unpolarized radiation incident along this axis
Polarized radiation scattered in this plane
Pictures by Matthew Hedman
Quadrupole patternQuadrupole patternQuadrupole patternQuadrupole pattern
Quadrupole pattern in the radiation will create polarization
Quadrupole pattern in the radiation will create polarization
Quadrupole moment in motion of charge
Radiation scattered along this axis has a polarized component
A view on the dynamic universeA view on the dynamic universeA view on the dynamic universeA view on the dynamic universe
Quadrupole moments from Temperature anisotropies will be washed out
Dynamics in the early universe determine the polarization spectrum
Quadrupole moments from Temperature anisotropies will be washed out
Dynamics in the early universe determine the polarization spectrum
Density fluctuations E-modesGravity waves E- and B-modes, Amplitude determined by scale of inflation
Different Polarization patternsDifferent Polarization patternsDifferent Polarization patternsDifferent Polarization patterns
E-Mode (scalar, even parity)E-Mode (scalar, even parity)
B-Mode (vector or tensor, odd parity)B-Mode (vector or tensor, odd parity)
Why did the CMB polarization Why did the CMB polarization escape detection for so long?escape detection for so long?Why did the CMB polarization Why did the CMB polarization escape detection for so long?escape detection for so long?
Highly sensitive detectorsHighly sensitive detectors
Excellent control of systematics Excellent control of systematics (atmospheric, instrumental) (atmospheric, instrumental)
Excellent angular resolutionExcellent angular resolution
Highly sensitive detectorsHighly sensitive detectors
Excellent control of systematics Excellent control of systematics (atmospheric, instrumental) (atmospheric, instrumental)
Excellent angular resolutionExcellent angular resolution
Tiny fluctuations (1 part in 1 million) on small angular scale Challenge for the experiments:
Tiny fluctuations (1 part in 1 million) on small angular scale Challenge for the experiments:
Comparison of Power SpectraComparison of Power SpectraComparison of Power SpectraComparison of Power Spectra
How to catch and query the witnesses?How to catch and query the witnesses?How to catch and query the witnesses?How to catch and query the witnesses?
Based at ground , balloon, space?Based at ground , balloon, space?
Which frequency to observe?Which frequency to observe?
Which techniques to use Which techniques to use (HEMT,Bolometers)?(HEMT,Bolometers)?
What is an optimal scanning strategy?What is an optimal scanning strategy?
Based at ground , balloon, space?Based at ground , balloon, space?
Which frequency to observe?Which frequency to observe?
Which techniques to use Which techniques to use (HEMT,Bolometers)?(HEMT,Bolometers)?
What is an optimal scanning strategy?What is an optimal scanning strategy?
Height in the atmosphere at which radiation is attenuated by a factor 1/2Height in the atmosphere at which radiation is attenuated by a factor 1/2
Atmospheric TransmissionAtmospheric Transmission
Are there false witnesses?Are there false witnesses?Are there false witnesses?Are there false witnesses?
Dust Synchrotron Point Sources
Dust Synchrotron Point Sources
Gravitational Lensing S-Z from Clusters ???
Gravitational Lensing S-Z from Clusters ???
Compilation by Matthew Hedman
DASI 30(13) 20‘ South PoleCBI 30(13) 3‘ Atacama (Chile)VLA 8.4 6‘‘ Socorro (New Mexico)ATCA 8.7(5) 2‘ AustraliaAMIBA 90(19) 2‘ Mauna Loa (Hawaii)SPORT 22,32,60,90 7° ISS, full skyMAP 22,30,40(2),60(2),90(4) 13‘ L2, full skyPLANCK-LFI 30(4), 44(6),70(12), 100(34) 33,23,13,10 L2, full skyBAR-SPORT 32,90 30‘,12‘ Antarctic LDBPOLAR 30 7° WisconsinCOMPASS 30 7° WisconsinPIQUE 40,90 30‘,15‘ New JerseyCAPMAP 40(4),90(10) 7‘,3‘ New JerseyPLANCK-HFI 100(4),143(12),217(12),
353(6),545(8),857(6) 11‘,8‘,6‘,5‘ L2, full skyB2K+X 150(4), 240(4) 340(4) 10‘ Antarctic LDBMAXIPOL 150(12) 420(4) 10‘ US BalloonBICEP 150(96) 0.7 ° South Pole (?) POLARBEAR 150(~3000) 10‘ South Pole POLATRON 90 2‘ OvroQUEST 100,150(~30) 6‘ Atacama (Chile)
DASI 30(13) 20‘ South PoleCBI 30(13) 3‘ Atacama (Chile)VLA 8.4 6‘‘ Socorro (New Mexico)ATCA 8.7(5) 2‘ AustraliaAMIBA 90(19) 2‘ Mauna Loa (Hawaii)SPORT 22,32,60,90 7° ISS, full skyMAP 22,30,40(2),60(2),90(4) 13‘ L2, full skyPLANCK-LFI 30(4), 44(6),70(12), 100(34) 33,23,13,10 L2, full skyBAR-SPORT 32,90 30‘,12‘ Antarctic LDBPOLAR 30 7° WisconsinCOMPASS 30 7° WisconsinPIQUE 40,90 30‘,15‘ New JerseyCAPMAP 40(4),90(10) 7‘,3‘ New JerseyPLANCK-HFI 100(4),143(12),217(12),
353(6),545(8),857(6) 11‘,8‘,6‘,5‘ L2, full skyB2K+X 150(4), 240(4) 340(4) 10‘ Antarctic LDBMAXIPOL 150(12) 420(4) 10‘ US BalloonBICEP 150(96) 0.7 ° South Pole (?) POLARBEAR 150(~3000) 10‘ South Pole POLATRON 90 2‘ OvroQUEST 100,150(~30) 6‘ Atacama (Chile)
Overview of Polarization ExperimentsOverview of Polarization ExperimentsExperiment Freq in GHz (#chan) Beamsize Location Experiment Freq in GHz (#chan) Beamsize Location TechniqueTechnique
Overview of Polarization ExperimentsOverview of Polarization ExperimentsExperiment Freq in GHz (#chan) Beamsize Location Experiment Freq in GHz (#chan) Beamsize Location TechniqueTechnique
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PrincetonD. Barkats, P. Farese, J. McMahon, S. T. Staggs + undergraduates
ChicagoC. Bischoff, M. Hedman, D. Samtleben, K. Vanderlind, B. Winstein+ undergraduates
MiamiJ. Gundersen, E. Stefaniescu
JPLT. Gaier
PrincetonD. Barkats, P. Farese, J. McMahon, S. T. Staggs + undergraduates
ChicagoC. Bischoff, M. Hedman, D. Samtleben, K. Vanderlind, B. Winstein+ undergraduates
MiamiJ. Gundersen, E. Stefaniescu
JPLT. Gaier
CAPMACAPMAPP
CAPMACAPMAPP
ChicagoChicago
MiamiMiami
JPLJPL
PrincetonPrinceton
Experimental setupExperimental setupExperimental setupExperimental setup Telescope at Crawford Hill (New Jersey), Telescope at Crawford Hill (New Jersey),
7 m dish, off-axis, Cassegrain, 0.05 FWHM 7 m dish, off-axis, Cassegrain, 0.05 FWHM beambeam
Correlation receiverCorrelation receiver
W-Band (84-100 GHz) and Q-Band (36-45 GHz)W-Band (84-100 GHz) and Q-Band (36-45 GHz)
This winter 4 horns, final design 14 hornsThis winter 4 horns, final design 14 horns
Scanning on a small cap (1 degree diameter) Scanning on a small cap (1 degree diameter) around NCParound NCP
Telescope at Crawford Hill (New Jersey), Telescope at Crawford Hill (New Jersey), 7 m dish, off-axis, Cassegrain, 0.05 FWHM 7 m dish, off-axis, Cassegrain, 0.05 FWHM beambeam
Correlation receiverCorrelation receiver
W-Band (84-100 GHz) and Q-Band (36-45 GHz)W-Band (84-100 GHz) and Q-Band (36-45 GHz)
This winter 4 horns, final design 14 hornsThis winter 4 horns, final design 14 horns
Scanning on a small cap (1 degree diameter) Scanning on a small cap (1 degree diameter) around NCParound NCP
Gx Gy (Ea - Eb )Gx Gy (Ea - Eb )
Ex = Ea - EbEx = Ea - Eb
Ey = Ea + EbEy = Ea + Eb
EbEb EaEa
ExEx
EyEy
MultiplierMultiplier
GyGy GxGx
22
Correlation PolarimeterCorrelation Polarimeter
Phase SwitchPhase Switch 1±1±
Signal size ~10 W Amplification crucial
Not affected by drift of relative gains but sensitive to relative phase shifts
Output from multiplier ~ Ex, Ey eliminated by use of phase switch: signal in one line multiplied by square wave, after multiplication demodulated
Signal size ~10 W Amplification crucial
Not affected by drift of relative gains but sensitive to relative phase shifts
Output from multiplier ~ Ex, Ey eliminated by use of phase switch: signal in one line multiplied by square wave, after multiplication demodulated
22 22
-18-18
Sensitivity of experimentsSensitivity of experimentsSensitivity of experimentsSensitivity of experiments
TTsyssys : : System System temperaturetemperature: : BandwidthBandwidthTTintint : : Integration timeIntegration timeG/GG/G : : Relative gain drift Relative gain drift of of amplifier ~ 1/famplifier ~ 1/fSS : : SensitivitySensitivity
TTsyssys : : System System temperaturetemperature: : BandwidthBandwidthTTintint : : Integration timeIntegration timeG/GG/G : : Relative gain drift Relative gain drift of of amplifier ~ 1/famplifier ~ 1/fSS : : SensitivitySensitivityLarge bandwidth and low system temperature desirable
Expected CAPMAP sensitivity: Large bandwidth and low system temperature desirable
Expected CAPMAP sensitivity:
int
2
int min
tt1TT )( S
GG
sys ≈Δ+Δ=Δ ν
smKS 4.0=
Elimination of Elimination of drifts by drifts by ‘chopping‘‘chopping‘
Elimination of Elimination of drifts by drifts by ‘chopping‘‘chopping‘
Taking the difference of two measurements at different spots on the sky (same azimuthal position) gets ríd off drifts
Taking the difference of two measurements at different spots on the sky (same azimuthal position) gets ríd off drifts
PIQUE data
Experimental setupExperimental setupExperimental setupExperimental setup
7m Telescope
Horn Radiometer RF IF IF
box
Data Acquisition
Horn Horn Horn Horn
Predicted and measured Beam Pattern
Model of the hornModel of the horn
15 cm15 cm
Schematics of CAPMAP radiometer
Schematics of CAPMAP radiometer Two different
temperature stages: 20 K and room temperature
In RF part rectangular waveguides, in IF part coaxial cables
Two different temperature stages: 20 K and room temperature
In RF part rectangular waveguides, in IF part coaxial cables
82 GHz
84-100 GHz
2-18 GHz
Setup at ChicagoSetup at ChicagoSetup at ChicagoSetup at Chicago
3 inch (7.6 cm)
IF sectionIF sectionIF sectionIF section
Phase matchingPhase matchingPhase matchingPhase matching
In-phase response
~A cos
In-phase response
~A cos
Out of phase response
(90 degree switch) ~A sin
Out of phase response
(90 degree switch) ~A sin
QuickTime™ and aMotion JPEG A decompressor
are needed to see this picture.
Data AcquisitionData AcquisitionData AcquisitionData Acquisition
PCI card, 32 channels
24 bit resolution
Sampling rate ~100 kHz, demodulation in software
Data rate ~250 Hz
7 GByte/day (final design 24 GByte/day)
PCI card, 32 channels
24 bit resolution
Sampling rate ~100 kHz, demodulation in software
Data rate ~250 Hz
7 GByte/day (final design 24 GByte/day)
Work at the telescope ...Work at the telescope ...Work at the telescope ...Work at the telescope ...
PIQUE setup at the telescopePIQUE setup at the telescopePIQUE setup at the telescopePIQUE setup at the telescope
First Data – Total Power First Data – Total Power ChannelsChannelsFirst Data – Total Power First Data – Total Power ChannelsChannels
Moon JupiterMoon Jupiter
Peak: 200 K Peak: 1 K
First Data – Polarization First Data – Polarization ChannelsChannelsFirst Data – Polarization First Data – Polarization ChannelsChannels
Moon Tau A (Crab Nebula)Moon Tau A (Crab Nebula)
Peak: 1 KPeak: 25 mK
AnalysisAnalysisAnalysisAnalysis
)2
1exp(
)det(
1)|( 1dCd
CCdP T −−∝
Measure temperature/polarization in a region of the sky and compare with expectation (likelihood analysis):
Measure temperature/polarization in a region of the sky and compare with expectation (likelihood analysis):
l-coverage determined by beam sizel-coverage determined by beam size
d : Data vector C = CN + CT
CN : Noise covarianceCT : Theory covariance
d : Data vector C = CN + CT
CN : Noise covarianceCT : Theory covariance
Expected SensitivityExpected SensitivityExpected SensitivityExpected Sensitivity
CAPMAP expectation
DASI result
CAPMAP expectation
DASI result
Summary and OutlookSummary and OutlookSummary and OutlookSummary and Outlook
CMB is the oldest light in the universeCMB is the oldest light in the universe
Provides direct view of the infant universe Provides direct view of the infant universe
Measurement of CMB Polarization is a big Measurement of CMB Polarization is a big experimental challenge, anisotropies of the order experimental challenge, anisotropies of the order of 1 part in 1 millionof 1 part in 1 million
CAPMAP uses a 7m telescope in New Jersey to CAPMAP uses a 7m telescope in New Jersey to observe the polarization at 90 and 40 GHzobserve the polarization at 90 and 40 GHz
Installation of 4 out of 14 horns underwayInstallation of 4 out of 14 horns underway
First data taking winter 2002/2003 First data taking winter 2002/2003
CMB is the oldest light in the universeCMB is the oldest light in the universe
Provides direct view of the infant universe Provides direct view of the infant universe
Measurement of CMB Polarization is a big Measurement of CMB Polarization is a big experimental challenge, anisotropies of the order experimental challenge, anisotropies of the order of 1 part in 1 millionof 1 part in 1 million
CAPMAP uses a 7m telescope in New Jersey to CAPMAP uses a 7m telescope in New Jersey to observe the polarization at 90 and 40 GHzobserve the polarization at 90 and 40 GHz
Installation of 4 out of 14 horns underwayInstallation of 4 out of 14 horns underway
First data taking winter 2002/2003 First data taking winter 2002/2003
Exciting time in cosmology, share it with us at the CfCP!Exciting time in cosmology, share it with us at the CfCP!