B Polarization Measurement of the CMB at the Concordia Station (Dôme C)
August 31, 20062nd Sino-French workshop B Polarization Measurement of the CMB at the Concordia...
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Transcript of August 31, 20062nd Sino-French workshop B Polarization Measurement of the CMB at the Concordia...
August 31, 2006 2nd Sino-French workshop
B Polarization Measurementof the CMB
at the Concordia Station (Dôme C)
Yannick Giraud-Héraud(APC - Paris)
August 31, 2006 2nd Sino-French workshop
OUTLINE
• reminder of CMB polarization parameters• challenges for CMB polarization measurements• observationnal status and forthcoming observations• BRAIN: an interferometer at Dôme C (Antartica) for measuring B mode polarization of the CMB
August 31, 2006 2nd Sino-French workshop
• Total intensity:
• Linear polarization:
I = <|Ex|2> + <|Ey|2>
Q = <|Ex|2> - <|Ey|2>
U = <|Ex’ |2> - <|Ey’ |2>
Ex(t)
Ey(t) x’
y’
Stokes Parameters
WMAP3 23 GHz
August 31, 2006 2nd Sino-French workshop
Can decompose Q & U into:• E-modes (even-parity): (or grad)
• B-modes (odd-parity): (or curl)
E-modes produced by all quadrupole sources (velocity gradients and gravitational waves)
B-modes produced by gravitational waves and lensing of E-modes
The E/B Decomposition
Pure E Pure B
Wayne Hu
August 31, 2006 2nd Sino-French workshop
Uses of CMB Polarization
• Tighter constraints on cosmological parameters• Gravity waves from inflation
• nature of gravity• test of inflation• energy scale• Planck-era physics?
• Lensing reconstruction• constraints on Dark Energy• neutrino mass measurement
August 31, 2006 2nd Sino-French workshop
CMB observables as probe for inflation
- r : ratio between the amplitude of tensor/scalar power spectrum
- nS, nT spectral indices of scalar and tensor power spectrum
- power spectrum of type B polarized anisotropies
access to primordial gravitational waves
WMAP3 alone: r<0.55 (95% C.L.) (GW<2.0 10-12)
(based on temperature power spectrum)
WMAP3 alone: ns=0.987+0.019-.0.037 (no running contribution)
August 31, 2006 2nd Sino-French workshopC. Rosset
( )17.0=τ
1.0=r
41055.6 −×=r€
E I ~ 2 ×1016GeV
GeVEI15107.5~ ×
€
r ≡T 2
S2∝
E I
M pl
⎛
⎝ ⎜ ⎜
⎞
⎠ ⎟ ⎟
4
What can we get from CMB polarization measurements?
August 31, 2006 2nd Sino-French workshopC. Rosset
Weak lensingE mode B mode
νm
énergie noire
€
τ =0.17( )
What can we get from CMB polarization measurements?
August 31, 2006 2nd Sino-French workshop
Polarization has been measured
Lens
IGW
DASI, CBI, BOOMERanG and CAPMAPhave all published polarization detections.
DASI
WMAP
August 31, 2006 2nd Sino-French workshop
Planck
• Full sky survey– CMB anisotropies
• Temperature and polarization• Resolution: 5’• Sensitivity: ∆T/T = 2.10-6
– Foregrounds
• 15 times more sensitive than WMAP
• Planck will be the ultimate experiment– for T up to l 2000,– for E up to l 1000 …
• … but will be able to detect B mode only if r is closed to its actual upper limit.
~100µK RMS
Mode E~4µK RMS
Mode B~300nK RMS
(Hu et al. 2002)
Planck, for a 14 months survey:
r=0.7
August 31, 2006 2nd Sino-French workshop
Planck Polarization(Planck Blue Book)
E spectra
B spectra
August 31, 2006 2nd Sino-French workshop
Which objectives for the CMB physics after Planck
- high-angular resolution Sunyaev-Zel’dovich effect
- increase the number of detectors to measure the polarized anisotropies polarisées with an optimization of the optical scheme to fight the systematic effects
Probe of the inflation epoch and of the Large Scale Structures
August 31, 2006 2nd Sino-French workshop
Sensitivity of forthcoming observations
(Task Force on Cosmic Microwave Background Research - July 2005)
E1 : 1000 detectors ; 1 year ; 6’ ; 4 % of the skyE2 : 1000 detectors ; 1 year ; 1’ ; 0,4 % of the skyE3 : 1000 detectors ; 1 year ; 30’ ; 100 % of the sky
E1
E2
E3
August 31, 2006 2nd Sino-French workshop
Long term effort
BICEPQUaD
ClOVEREBEXPolarBearQUIET
CMBpol (NASA & ESA)SAMPAN (CNES)
~2005
~2008-2010
>2015
eV 03.0=νm(Kaplinghat et al. 2003)
Gravitational wavesGravitational waves
(Ken Ganga 2004)
QUaD, BICEP (2005-2008)
CLOVER, EBEX, POLARBEAR, BRAIN (2008-2011)
SAMPAN, CMBPOL(> 2018)
August 31, 2006 2nd Sino-French workshop
French-ItalianConcordia Station at Dôme C
August 31, 2006 2nd Sino-French workshop
Concordia Station at Dôme C
• 3 traverses (12-15 days) from Dumont d’Urville to
Dôme C (1100 km) every Summer (3x150 tonnes)
4 hours flight from Terra Nova Bay with Twin Otter• first Winter season from February 2006 to
September 2006 with 13 overwinterers• Excellent atmospheric transmission all over the year
winter averagepwv = 250 m
Data South Pole
No measurement during the Winter Season in mm wavelenghts: site testing needed
Dome A
Zhongshang
Dumont d’Urville
August 31, 2006 2nd Sino-French workshop
Optical Depth for3 sites :- Chajnantor (ALMA)- Pôle Sud- Mauna Kea
Transmission = eτ
Peterson et al. 0211134
1 year Dôme C = 2 years South Pole =5 years Atacama Plateau
(e-1/e-3 = 7,4)
August 31, 2006 2nd Sino-French workshop
Polarization of the atmosphere
• Zeeman Effect on the oxygene lines
• Circular Polarization– Estimation:
100µK CMB
(Modes B: <300nK RMS)
August 31, 2006 2nd Sino-French workshop
Sky Coverage
Projection of the foregrounds at 150 GHz (centered on the South Pole)
The 2 circles are at declinations -40° et -80° (Dôme C at -74°30’)
The upper region between the 2 circles is a potential zone for observation
Ability to observe always the same part of the sky
Scanning direction changes with time
August 31, 2006 2nd Sino-French workshop
The instrument at Concordia (January 2006)
BRAIN
Collaboration France-Italy-UK(Rome, Milan, Cardiff, APC, CSNSM, CESR, IAS, LISIF)
August 31, 2006 2nd Sino-French workshop
BRAIN: a prototype of bolometric interferometer
Why an interferometer ?
• sensitivity similar to a photometer
• direct measurement of the Stokes parameters (e.g. Cl)
• differential measurement
reduction of atmospheric noise
• simplified optical set-up (no mirror)
reduction of systematic effects (atmosphere, far side lobes, …)
Horns
Ortho-Mode Transducers
Phase shifters
Beam combiners
Bolometers
August 31, 2006 2nd Sino-French workshop
1) Pathfinder
Objectives:• automatic monitoring of the cryogenic system (300 mK) during the Winter season• achieve the control of the experiment from Europe which implies satellite telemetry (INMARSAT, IRIDIUM, …)• measurement of the atmospheric noise during the Winter at 150 GHz (intensity and polarization)
2) Validation of the interferometry approach in the millimetric domain using bolometers
• at room temperature in the laboratory• at Dôme C with 6 baselines
BRAIN : 2 STEPS - 2006-2008
August 31, 2006 2nd Sino-French workshop (January 2006)
August 31, 2006 2nd Sino-French workshop
BRAIN 2: looking for primordial B modes
• Dôme C (Antartica)
• 3 telescopes at 90, 150 and 220 GHz
• 3 interferometers of 16x16 horns with bolometric read-out
– 50 < l < 150
• Starting in 2009?
R=0.1
R=0.01
R=0.001
(Clément Cressiot, 2006)
August 31, 2006 2nd Sino-French workshop
August 31, 2006 2nd Sino-French workshop
BOOMERanG and CBI Measurements
Montroy, et al.
Neither BOOMERanG nor CBIhave detected any BB at the levelof the EE polarization signals.This limits the foregrounds in theirregions.
August 31, 2006 2nd Sino-French workshop
Optique froide (Cardiff)
Prototype:
Cornets Archeops:
August 31, 2006 2nd Sino-French workshop
Optique froide (Cardiff)
Prototype:
Cornets Archeops:
August 31, 2006 2nd Sino-French workshop
Déphaseur à 4K
• Responsabilité APC-LISIF• Déphaseur diélectrique• Actionneur piézoélectrique• Statut:
– Simulations réalisées
– Design figée
– En réalisation au BE
– Tests en septembre 2005
August 31, 2006 2nd Sino-French workshop
Sensitivity comparison between total power array of bolometers and bolometric interferometer
Total # of photons:A: area main dish: solid angle of single pixel
⋅AN Total # of photons:A’: area input horn’: solid angle of input horn
''⋅AN
sensitivity is equal when ''⋅=⋅ ANAN