reionization science from the cmb after planck
DESCRIPTION
Reionization science from the CMB after Planck. Michael Mortonson. University of Chicago. July 2, 2009. Outline 1. Outline. Current reionization constraints and expected improvements from Planck and CMBPol (large-scale polarization) optical depth - PowerPoint PPT PresentationTRANSCRIPT
Reionization science from the CMB after Planck
Michael Mortonson
University of Chicago
July 2, 2009
Reionization Science from the CMB After Planck
Michael MortonsonU Chicago/KICP
2
Outline
July 2, 2009
Reionization report from June 2008 Fermilab CMBPol workshop:Zaldarriaga, Colombo, Komatsu, Lidz,
Mortonson, Oh, Pierpaoli, Verde, & ZahnarXiv:0811.3918
• 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
July 2, 2009 Michael MortonsonU Chicago/KICP
3
The End of Reionization
Fan, Carilli, & Keating (2006)
Reionization Science from the CMB After Planck
Michael MortonsonU Chicago/KICP
4
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
Michael MortonsonU 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
Michael MortonsonU 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
Michael MortonsonU Chicago/KICP
7July 2, 2009
Optical Depth
WMAP = 0.017
Planck = 0.005
CMBPol = 0.0025
[Fermilab report]
WMAP
CMBPol
Reionization Science from the CMB After Planck
Michael MortonsonU 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
Michael MortonsonU Chicago/KICP
9July 2, 2009
Physical Models
Simple model – assume that DM halos of mass M > Mmin hostradiation sources that ionize regions of mass M:
[Fermilab report]
WMAP
Planck
CMBPol
Reionization Science from the CMB After Planck
Michael MortonsonU 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
Michael MortonsonU 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:
http://background.uchicago.edu/camb_rpc
Reionization Science from the CMB After Planck
Michael MortonsonU Chicago/KICP
12July 2, 2009
General Reionization Histories
Reionization Science from the CMB After Planck
Michael MortonsonU Chicago/KICP
13July 2, 2009
General Reionization Histories
Reionization Science from the CMB After Planck
Michael MortonsonU 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
Michael MortonsonU 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
Michael MortonsonU 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
Michael MortonsonU 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