1. Fingerprints in the CMB from Reionization Gil Holder

2. Outline How reionization affects the CMB Small scale temperature anisotropy from velocities Small scale polarization anisotropy from patchy reionization South Pole Telescope Related talks: Weller, Diego, Iliev

3. Free Electrons and the CMB Screening –Suppresses background fluctuations Scattering –New photons red/blueshifted due to bulk motion of electon cloud –Quadrupole anisotropy in radiation field generates linear polarization South Pole Telescope Picture by Keith Vanderlinde http://photolibrary.usap.gov/

4. Effect on CMB TT Power free electrons with non- zero velocities and density fluctuations Second- order effect (so, small) Varying z of reionization

5. Complications to understanding the OV effect Electron fraction –Ionization history and patchiness important »E.g., Knox et al 1998, Gruzinov & Hu 1998 Velocities –Non-linear velocities damped by pressure »E.g., Ma & Fry 2002, Hu 2000 Cosmological parameters –Sensitive to peculiar velocities, densities »E.g., Jaffe & Kamionkowski 1998

6. Complications I & II: physics Need high resolution to resolve sources Need large volumes to get velocities right Iliev et al 2007

7. Complication III: cosmology WMAP5 allowed range in OV effect: factor of 2 or so - main scaling:  8 (4-6) (Zhang et al 2004, Dudley in prep) 2.0 4.0 1.0 OV Power (uK 2 )Non-linear OV Power (uK 2 ) Dudley

8. CMB Polarization quadrupole anisotropy + Thomson scattering =polarization

9. Thomson optical depth/21cm anti-correlation Holder, Iliev & Mellema densityThomson optical depth21cm fluctuations

10. Some equations… 21 cm fluctuations Optical depth Optical depth fluctuations 21 cm - (optical depth) anti-correlation

11. Quadrupole Sources Primary CMB anisotropy –Coherent over dz of a few –Sensitive to large scale structure inside our horizon Kinematic quadrupole (small) –Doppler effect at second order –Sensitive to peculiar velocities of ionized regions Dore et al 2007 Coherence of local Q along line of sight

12. CMB Pol. & Patchy Reionization Unlikely to be a problem for inflation B modes Patchy reionization signal below lensing! Nearly equal E&B: most of the patchy signal from a narrow range in z Strongly non- Gaussian

13. E-modes/B-modes E-modes vary spatially parallel or perpedicular to polarization direction B-modes vary spatially at 45 degrees CMB scalar perturbations only generate *only* E Patchy reionization: polarization direction set by quadrupole direction but spatial variations set by optical depth fluctuations Image of positive kx/positive ky Fourier transform of a 10x10 deg chunk of Stokes Q CMB map [simulated; nothing clever done to it] E modes

14. Aside: Matched Filtering The best way to look for a signal in noise with a known power spectrum is a matched filter (e.g., Haehnelt & Tegmark) The generalization for a signal that is symmetric in a Stokes parameter (like a bubble during reionization: Signal-to-noise in a temperature map Signal-to-noise in a Stokes Q or U map

15. “Getting around cosmic variance” Remote quadrupoles from galaxy clusters is an old idea (Kamionkowski & Loeb 1997) Reionization bubbles have the same optical depth contrast, but are not coincident with a large galaxy cluster (SZ, radio halos, grav. lensing, cluster galaxies, intracluster dust) Numerology: Reionized bubble: 1 physical Mpc at z=9 at 1000 times current background density Galaxy cluster: 1 physical Mpc at z=0 at 200 times current background density

16. The benefits of collaborators at z~10 Surface of last scattering at z=10 has little overlap with ours More than 1/2 of signal from “dark ages” Good enough data over large patch of sky allows reconstruction of “initial conditions” for most of Hubble volume Kinematic quadrupoles would allow reconstruction of velocity field at reionization Needs polarized 0.1 uK on arcminute scales and mK redshifted 21 cm Comoving distance

17. How hard is this? Need 100 nK in CMB polarization on arcminute scales –Basically ALMA-level collecting area Need few mK at wavelengths of few m (likely needs SKA) for imaging Radio point sources will be particularly nasty Big bubbles around largest sources could have 10x larger signal and detectable with current technology Stacking of CMB and/or radio data would relax these requirements…. Hard, even for SPT-Pol

18. The South Pole Telescope 10m telescope at south pole working at mm wavelengths 960 bolometers, TES/squid readout, frequency multi- plexed 90/150/220 GHz Basically fully online Expect ~100 sq deg per month to ~15 uK sensitivity at 1’ resolution Moon shining behind SPT Photo by Zak Staniszewski and Steve Padin

19. SPT Collaboration

20. Pointed Cluster SZ Maps Chandra X-ray Image 140 hour observation (0.5 Ms) SZ Image of Bullet Cluster z =.297 7 hours of observation ~ 20  K RMS per 60” pixel Brad Benson and Tom Plagge

21. 150 GHz 5h field map150 GHz 23h field map 1 st SPT Survey fields at RA 5h & RA 23h Mapped with interleaved azimuth raster scans (lead-trail on 23h field) ~800 hours of observation each ~100 deg 2 each with ~16 uK noise in 1-arcminute pixels Overlap with optical BCS griz data in each field

22. Zoom in on 23h field map Lots of bright point sources ~15-sigma SZ cluster detection These “large-scale” fluctuations are primary CMB.

23. First Blind Detection I The four most significant SPT 150 GHz detections in region overlapping 40 deg 2 BCS5h30m field Submitted to ApJ; Staniszewski et al, astro-ph/0810.1578

24. First Blind Detection I The four most significant SPT 150 GHz detections in region overlapping 40 deg 2 BCS5h30m field Submitted to ApJ; Staniszewski et al, astro-ph/0810.1578

25. The number counts aren’t crazy Optical follow- up reasonably complete Simulated constraints with area similar to current well- understood, reasonably optically complete sample FAKE Shaw Dudley

26. South Pole Telescope sensitivity Sample variance limited over 4000 square degrees every month to l ~2000 kSZ/OV is buried deep Tom Crawford High  8

27. Clustering of Point Sources Radio and IR/submm sources presumably trace the large scale matter fluctuations Back of the envelope: –Power spectrum contribution: mean T 2 x projected clustering amplitude –Arcminute scales: few Mpc has clustering ~1 in 3D, divide by number of independent cells along line of sight => 1e-3

28. Extrapolate ARCADE results to 150 GHz: 5uK Extrapolate source models: less than 1 uK –=> << 1uK 2 clustering power at 150 GHz Aside: ARCADE extrapolation to 30 GHz: T~200 uK 30 GHz clustering power could be >50 uK 2 However: widely agree that ARCADE results are hard to reconcile with known populations Radio Source Clustering Fixsen et al 2009

29. IR/Submm Source Clustering Mean T cmb ~10 4 uK at 500 um (FIRAS) Clustering amplitude 10 -3 => few 10 5 uK2 BLAST: 10 6 uK 2 Mean T cmb ~50 uK at 150 GHz (FIRAS, number counts) => few uK 2 We do actually have a clustering model BLAST: Viero et al 2009

30. Estimate of the 150 GHz Sky Wow, there is a lot of stuff in the sky! Low   leads to much lower power Multi-frequency observations are essential (and we have them) SZ power spectrum analysis ongoing ~20x more data by end of survey (going until at least end of 2010) 100 deg 2

31. Summary Lots of common signal between 21cm and CMB (both temperature and polarization) CMB sees electrons, 21cm sees !(electrons) CMB signal is small on small scales, but loaded with information about reionization and large scale structure Remote quadrupoles (primordial & kinematic) projected optical depth maps South Pole Telescope is up and running well ~100 galaxy clusters discovered in SZ could hit reionization signal in the next year (if we can dig it out)