The CMB and Gravity Waves John Ruhl Case Western Reserve University 3/17/2006, CERCA at St. Thomas

WMAP 3yr temperature maps… what the sky really looks like. (What the sky really looks like) 23 GHz 33 GHz 41 GHz 61 GHz 94 GHz

WMAP 3-year map, “galaxy subtracted”

Boomerang “T” maps B03: 150GHz (published) 10’ resolution, ~1000 sq. deg.

Acbar maps 150GHz, 5’ resolution, 10’s of sq. deg, More coming soon.

Power spectra =>  CDM looks good Power Spectrum (uK 2 ) Legendre l

B03 power spectrum =>  CDM still looks good

WMAP(3yr)+others Figure 18, Hinshaw etal, WMAP 3-year release

WMAP 3yr data… theory-scaled to high-ell… Fig 5, Spergel etal, WMAP 3-year release

“Post B03” (pre-WMAP3) parameters MacTavish etal, B03 release

Still of interest r = T/S: primordial gravity waves (tensor modes) n T : spectral index of tensor mode power spectrum n s : spectral index of density perturbation power spectrum, Dark Energy w, w’, etc non-gaussianity Isocurvature modes Suprises: eg “not flat”, obs. disagreements, etc.

n s vs r : current limits Plot from M. Tegmark, TFCR report r  T/S n s CMB “goal” WMAP 3yr, r<0.28 (95%CL) w/SDSS

CMB polarization Two causes: 1.“Normal”  CDM: Density perturbations at z=1000 lead to velocities that create local quadrupoles seen by scattering electrons. => “E-mode polarization” (no curl) 2.Gravity waves: create local quadrupoles seen by scattering electrons, => “B-mode polarization” (curl)

Both are caused by the polarization dependence in Thomson scattering

Anisotropic illumination => polarization Green = probability of emitting in that direction… Observer Vertical pol. No emission to observer Horizontal pol. (in and out of page) Line of sight

Gravity Wave Surface of last scattering Gravity waves at z=1000

… create local quadrupoles around an electron at z=1000.

Flavors of CMB polarization Two patterns: Density perturbations: curl-free, “E-mode” Gravity waves: curl, “B-mode”

IAU convention for Q and U North East + - Q North East U + - Each point on the sphere has a Q or U value determined by the polarization at that point. Linear polarization Stokes parameters

Stokes Parameters vs. E and B mode The E-mode (or B-mode) value at a point on the sphere depends on the polarization pattern all around it. Direction you’re looking on the sky (2 components) Same thing, but variable for integration Polar coordinates of relative to Weighting function (Note: w=0 for theta =0)

E and B mode patterns Blue = + Red = - “local” Q“local” U For a given circle ( ), circumference goes as, while, so the contribution of that circle goes as 1/.

E and B mode patterns Unchanged under parity flip Sign reverses under parity flip E-mode B-mode Seljak and Zaldarriaga, astro-ph/

E-mode polarization (simulation) Seljak and Zaldarriaga, astro-ph/ Color: |E| Bars: E-mode polarization direction and size

B-mode polarization (simulation) Seljak and Zaldarriaga, astro-ph/ Color: |B| Bars: B-mode polarization direction and size

TE-mode polarization (simulation) Seljak and Zaldarriaga, astro-ph/ Color: T Bars: Rotated 45deg to turn E into B.

TE-mode polarization (correlated only) Seljak and Zaldarriaga, astro-ph/ Color: E-field Bars: E pol

CMB Polarization power spectra Primordial B-modes Reionization bump Shape and amplitude of EE are predicted by  CDM. ``Shape” of BB is predicted “scale- invariand GW’s”. Amplitude of BB is model dependent.

The State of CMB polarization measurements

WMAP, Kogut etal Fig 22, Hinshaw etal, WMAP 3yr release

EE power spectrum data

Figure 22, Page etal, WMAP 3-yr release.

B03 and WMAP 3yr

High-l BB power spectrum data

CMB Polarization power spectra Current “high-l” BB limits

WMAP Polarization data BB limit (1sigma) r=0.3 BB Foreground model Figure 25, Page etal, WMAP 3yr release Current “high-l” BB limits

Measurements to date

Reionization

The Future of CMB polarization measurements Foregrounds Technology

Foregrounds at l=50 S. Golwala, 2005 r = 0.01 Dust Synchrotron

Galactic Foregrounds: l-space From G. Hinshaw, TFCR report

“Future, large angular scale” CMB Polarization Experiments deployed funded proposed Quad: NTD bolo, 90/150 GHz, ~0.2deg, ~100 elements. Spole. Bicep: NTD bolo, 90/150 GHz, ~1deg, ~100 elements, Spole Ebex: SC Bolos, GHz, ~0.2deg, ~1000 elements, balloon Pappa: SC bolos, 90/150GHz, ~1deg, ~20 elements, balloon Clover: SC bolos?, GHz?, ~1deg, ~1000 elements, Chile Quiet: Hemts, ??? freqs/elements, Chile Polarbear: SC bolos, 90/150/220GHz, ~0.2deg, ~? Elements, Chile Spider: SC bolos, GHz, ~1deg, ~1000 elements, balloon CMBPOL: ???, satellite [see TFCR (aka “Weiss”) report]

Sensitivities Plot from T. Montroy

Predicted Future Experiment Sensitivities From G. Hinshaw, TFCR report

Systematics to conquer Table 6.1 from TFCR report

Experiment strengths and weaknesses

On-chip modulator (continuous) Detectorfeed(s)Other optics “on chip” modulatorphotons

On-chip modulator (two state)

“After primary” modulator (continuous) Detectormodulator feed(s)Other optics “on chip” photons

“Ideal” Future experiment to probe Inflation Lots of sensitive detectors and integration time “Good enough” angular resolution (to measure l=100 bump) “Large enough” sky coverage (to measure reionization bump) Low systematics, polarization modulator… optimized for Polarization. Ultimate instrument: CMBPOL satellite Realistic (proposed) instrument…

Spider (CMBPOL on a rope) Canada: U. Toronto, U.BC UK: Cardiff, Imperial Coll. London USA: Caltech, Case, JPL, NIST A balloone-borne “low l” machine

Six frequency bands Six telescopes Clean refractor optics Halfwave plates

CIT/JPL Polarized Array 8x8=64 pixel phased-array “patches”, 2 polarizations on each.

JPL Antenna-coupled bolometer, and crossed dipole elements

Around the world flight from Australia, night time observing only Large sky coverage => get to low l

Half wave plate polarization Modulator High index Low index 6” diameter birefringent sapphire plate Challenges: AR coating “well enough”, cryogenic “fast” rotation

Half wave plate polarization Modulator Linear polarization sent through plate to aligned linearly polarized detector Plate rotation angle (about 1 rotation) Signal R R B B 45

Spider baseline bands and sensitivities 1856 detectors 6 bands

Sensitivities Plot from T. Montroy

Benefit of measuring the Reionization bump Plot from C.L. Kuo (1 year) WMAP 3-year EE: tau = WMAP 3-year all: tau =

Summary 1.CMB polarization may contain “fingerprints” of gravity waves at z=1000 and z=30ish, 2. The technology for such measurements is rapidly being brought to the field, and prospects look very good.

THE END

Epsilon vs. a From the NASA/NSF/DOE Task force on CMB research report, 2005

Epsilon vs. a From the NASA/NSF/DOE Task force on CMB research report, 2005

Reheating Remember: kinetic term exponential expansion. As inflation “starts to end”:

GW Omega(f)

Hi gang, ﾊﾊﾊﾊﾊﾊﾊ vis-a-vis our discussion this morning, here are approximate specs on several experiments that are in operation or being built that will search for B-modes at ell ~ 30 -> 100. ﾊﾊﾊﾊﾊﾊﾊ Of these, the performance estimates for BICEP (Hivon) are the most dated, followed by EBEX (? Bacigallupi?) and then QUIET (?Gorski?), which are the most recent. ﾊ The QUIET site goes into some detail about what effects have and have not been included in their performance estimates. ﾊﾊﾊﾊﾊﾊﾊ I hope to talk to Gorski today to find out what may or may not have been already done for Planck and QUIET.aBICEP20 x 40 degrees at 1 degree resolutionQUIET:20 x 20 degrees at 14 arcmin4 x 4 degrees at 3.5 arcminhttp://quiet.uchicago.edu/index.phpEBEX:20 x 30 degrees at 8 arcminhttp://groups.physics.umn.edu/cosmology/ebex/index.htmlhttp://arxiv.org/abs/astro-ph/