CMB Polarization from Patchy ReionizationGil Holder

OutlinePatchy reionizationCMB polarizationCorrelation with redshifted 21cm radiationRemote quadrupole measurements & Hubble volume 3D reconstruction

Patchy ReionizationFirst stars ``blow bubbles in cosmic webStrongly inhomogeneousBubbles growing, becoming more numerous, range in bubble sizesFurlanetto et al

CMB Polarization quadrupoleanisotropy+ Thomson scattering =polarization

Polarization from Patchy ReionizationVery small scalesVery small signalDore et al

CMB Pol. & Patchy ReionizationUnlikely to be a problem for inflation B modesMainly confined to single Stokes componentDore et al

Thomson optical depth/21cm anti-correlationHolder, Iliev & MellemaMass densityThomson optical depth21 cm emission(slice dz~1; 100 Mpc on a side)

Some equations21 cm fluctuationsOptical depthOptical depth fluctuations21 cm - (optical depth) anti-correlation

Thomson optical depth/21cm anti-correlationHolder, Iliev & MellemaEarly times: blowing bubbles (ionize and awe)Late times: last throes of neutral overdense regions

The benefits of alien collaborators at z~10Surface of last scattering at z=10 has little overlap with oursMore than 1/2 of signal from dark agesGood enough data over large patch of sky allows reconstruction of initial conditions for most of Hubble volumeNeeds polarized 0.1 uK on arcminute scales and mK redshifted 21 cm

Comparison with Galaxy ClustersZ~9 : mean density x1000, comoving 10 Mpc=1 MpcAt z=0, this is a galaxy cluster!Remote quadrupoles with galaxy clusters suggested by Kamionkowski & LoebZ=10 has less overlap with z=0 CMBOptical depth from 21cm instead of ???No galaxy cluster in the field (radio halos, AGN, CMB lensing) SZ Image by Laurie Shaw

How hard is this?Need 100 nK in CMB polarization on arcminutes scales (basically 100 times the collecting area of APEX)Need few mK at wavelengths of few m (likely needs SKA)Radio point sources will be particularly nastyBig bubbles around largest sources could have 10x larger signal and detectable with current technology

Summary

Fine-scale polarization measurements allow new cosmological insightsRedshifted 21cm emission well anti-correlated with CMB polarization Cross-comparison allows measurement of quadrupoles at z~10 (but signals are small)21cm gives you optical depthCMB polarization=optical depth * quadrupolemK radio signal and 100 nK CMB pol on 1 scales