Reionization science from the CMB after Planck Michael Mortonson University of Chicago July 2, 2009

Reionization Science from the CMB After Planck Outline 1 Michael Mortonson U Chicago/KICP 2 Outline July 2, 2009 Reionization report from June 2008 Fermilab CMBPol workshop: Zaldarriaga, Colombo, Komatsu, Lidz, Mortonson, Oh, Pierpaoli, Verde, & Zahn arXiv: Current reionization constraints and expected improvements from Planck and CMBPol (large-scale polarization)  optical depth  physical parameters (reionization sources)  model-independent information Separating reionization from other phenomena (e.g. inflation)

Reionization Science from the CMB After Planck Reionization July 2, 2009 Michael Mortonson U Chicago/KICP 3 The End of Reionization Fan, Carilli, & Keating (2006)

Reionization Science from the CMB After Planck Michael Mortonson U Chicago/KICP 4 Reionization peak Reionization from Large-Scale E-modes July 2, 2009 Free electrons from reionization rescatter CMB photons Local quadrupole generates polarization Scattering at low redshifts projects onto large angular scales

Reionization Science from the CMB After Planck Usual approach: inst. reion. Michael Mortonson U Chicago/KICP 5July 2, 2009 WMAP Optical depth:  = 0.09 ± 0.02 Mortonson & Hu (2008) Allowed effects of reionization at 6<z<30

Reionization Science from the CMB After Planck Usual approach: inst. reion. Michael Mortonson U Chicago/KICP 6July 2, 2009 Planck and CMBPol Expect improved constraints on: optical depth (time of reionization) parameters of physical reionization models general reionization histories

Reionization Science from the CMB After Planck Usual approach: inst. reion. Michael Mortonson U Chicago/KICP 7July 2, 2009 Optical Depth WMAP   = Planck   = CMBPol   = [Fermilab report] WMAP CMBPol

Reionization Science from the CMB After Planck Usual approach: inst. reion. Michael Mortonson U Chicago/KICP 8July 2, 2009 Optical Depth Does the optical depth come from high z or low z? [Fermilab report] WMAP Planck CMBPol

Reionization Science from the CMB After Planck Usual approach: inst. reion. Michael Mortonson U Chicago/KICP 9July 2, 2009 Physical Models Simple model – assume that DM halos of mass M > M min host radiation sources that ionize regions of mass  M: [Fermilab report] WMAP Planck CMBPol

Reionization Science from the CMB After Planck Usual approach: inst. reion. Michael Mortonson U Chicago/KICP 10July 2, 2009 General Reionization Histories Models of reionization may not capture all relevant physical processes How much information about the general evolution of the ionization fraction can we get from large-scale CMB polarization (regardless of what it tells us about particular models)?

Reionization Science from the CMB After Planck Usual approach: inst. reion. Michael Mortonson U Chicago/KICP 11July 2, 2009 General Reionization Histories Models of reionization may not capture all relevant physical processes How much information about the general evolution of the ionization fraction can we get from large-scale CMB polarization (regardless of what it tells us about particular models)? CAMB/CosmoMC module for general reionization models:

Reionization Science from the CMB After Planck Usual approach: inst. reion. Michael Mortonson U Chicago/KICP 12July 2, 2009 General Reionization Histories

Reionization Science from the CMB After Planck Usual approach: inst. reion. Michael Mortonson U Chicago/KICP 13July 2, 2009 General Reionization Histories

Reionization Science from the CMB After Planck Second parameter Michael Mortonson U Chicago/KICP 14 Reducing Reionization Confusion Stronger constraints on reionization parameters will improve constraints on parameters degenerate with reionization Example: inflationary features in CMB temperature and polarization July 2, 2009

Reionization Science from the CMB After Planck Second parameter Michael Mortonson U Chicago/KICP 15 Adams et al (2001), Covi et al. (2006) July 2, 2009 Inflationary features and reionization

Reionization Science from the CMB After Planck Second parameter Michael Mortonson U Chicago/KICP 16 Inflationary features and reionization Mortonson, Dvorkin, Peiris, & Hu (2009) July 2, 2009 Planck: 2-3  CMBPol: 5-6 

Reionization Science from the CMB After Planck Summary Michael Mortonson U Chicago/KICP 17 Summary Future polarization data will improve constraints on reionization parameters – several times more precise than WMAP. Can measure up to ~5 parameters describing the ionization history. Precise determination of physical parameters or reconstruction of the ionization history will likely require additional information. Potential confusion between effects of reionization and other large-scale polarization parameters can be greatly reduced. July 2, 2009