B Polarization Measurement of the CMB at the Concordia Station (Dôme C)

1. B Polarization Measurement of the CMB at the Concordia Station (Dôme C) Yannick Giraud-Héraud (APC - Paris) 2nd Sino-French workshop

2. 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 2nd Sino-French workshop

3. Ey(t) x’ Ex(t) y’  Stokes Parameters WMAP3 23 GHz • Total intensity: • Linear polarization: I = <|Ex|2> + <|Ey|2> Q = <|Ex|2> - <|Ey|2> U = <|Ex’|2> - <|Ey’|2> 2nd Sino-French workshop

4. The E/B Decomposition 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 Wayne Hu Pure E Pure B 2nd Sino-French workshop

5. 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 2nd Sino-French workshop

6. CMB observables as probe for inflation - r : ratio between the amplitude of tensor/scalar power spectrum WMAP3 alone: r<0.55 (95% C.L.) (WGW<2.0 10-12) (based on temperature power spectrum) - nS,nTspectral indices of scalar and tensor power spectrum WMAP3 alone: ns=0.987+0.019-.0.037 (no running contribution) • power spectrum of type B polarized anisotropies • access to primordial gravitational waves 2nd Sino-French workshop

7. What can we get from CMB polarization measurements? C. Rosset 2nd Sino-French workshop

8. What can we get from CMB polarization measurements? Weak lensing E mode  B mode énergie noire C. Rosset 2nd Sino-French workshop

9. Polarization has been measured DASI, CBI, BOOMERanG and CAPMAP have all published polarization detections. WMAP DASI Lens IGW 2nd Sino-French workshop

10. (Hu et al. 2002) ~100µK RMS Mode E ~4µK RMS Mode B ~300nK RMS 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. Planck, for a 14 months survey: r=0.7 2nd Sino-French workshop

11. Planck Polarization (Planck Blue Book) E spectra B spectra 2nd Sino-French workshop

12. 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 2nd Sino-French workshop

13. Sensitivity of forthcoming observations E1 E3 E2 E1 : 1000 detectors ; 1 year ; 6’ ; 4 % of the sky E2 : 1000 detectors ; 1 year ; 1’ ; 0,4 % of the sky E3 : 1000 detectors ; 1 year ; 30’ ; 100 % of the sky 2nd Sino-French workshop (Task Force on Cosmic Microwave Background Research - July 2005)

14. Long term effort QUaD, BICEP (2005-2008) ~2005 BICEP QUaD CLOVER, EBEX, POLARBEAR, BRAIN (2008-2011) ~2008-2010 ClOVER EBEX PolarBear QUIET SAMPAN, CMBPOL (> 2018) Gravitational waves >2015 CMBpol (NASA & ESA) SAMPAN (CNES) (Ken Ganga 2004) (Kaplinghat et al. 2003) 2nd Sino-French workshop

15. French-Italian Concordia Station at Dôme C 2nd Sino-French workshop

16. Concordia Station at Dôme C winter average pwv = 250 m • 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 Dome A Data South Pole Zhongshang No measurement during the Winter Season in mm wavelenghts: site testing needed 2nd Sino-French workshop Dumont d’Urville

17. Optical Depth for • 3 sites : • Chajnantor (ALMA) • Pôle Sud • Mauna Kea Transmission = e-t (e-1/e-3 = 7,4) 1 year Dôme C = 2 years South Pole = 5 years Atacama Plateau Peterson et al. 0211134 2nd Sino-French workshop

18. Polarization of the atmosphere • Zeeman Effect on the oxygene lines • Circular Polarization • Estimation: 100µK CMB (Modes B: <300nK RMS) 2nd Sino-French workshop

19. 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 2nd Sino-French workshop

20. BRAIN The instrument at Concordia (January 2006) Collaboration France-Italy-UK (Rome, Milan, Cardiff, APC, CSNSM, CESR, IAS, LISIF) 2nd Sino-French workshop

21. 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 2nd Sino-French workshop

22. BRAIN : 2 STEPS - 2006-2008 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 2nd Sino-French workshop

23. 2nd Sino-French workshop (January 2006)

24. R=0.1 R=0.01 R=0.001 (Clément Cressiot, 2006) 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? 2nd Sino-French workshop

25. 2nd Sino-French workshop

26. BOOMERanG and CBI Measurements Neither BOOMERanG nor CBI have detected any BB at the level of the EE polarization signals. This limits the foregrounds in their regions. Montroy, et al. 2nd Sino-French workshop

27. Optique froide (Cardiff) Cornets Archeops: Prototype: 2nd Sino-French workshop

28. Optique froide (Cardiff) Cornets Archeops: Prototype: 2nd Sino-French workshop

29. Déphaseur à 4K • Responsabilité APC-LISIF • Déphaseur diélectrique • Actionneur piézoélectrique • Statut: • Simulations réalisées • Design figée • En réalisation au BE • Tests en septembre 2005 2nd Sino-French workshop

30. Sensitivity comparison between total power array of bolometers and bolometric interferometer Total # of photons: A: area main dish : solid angle of single pixel Total # of photons: A’: area input horn ’: solid angle of input horn sensitivity is equal when 2nd Sino-French workshop