Modeling Cosmic Reionization (Leave No Photon Behind)

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Modeling Cosmic Reionization(Leave No Photon
Behind)

• Nick Gnedin

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Co-starring
Gayler Harford
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Balancing the Books
(Bunker et al. 2004)
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Simulations
Space
Mass
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Numerical Challenges

• Enough resolution to do reionization right
• (resolving Lyman-limit systems)
• Enough volume to model observable
• (i.e. bright enough) galaxies

Observation
Simulation
Bigger simulation
Deeper observation
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We Do Not Know Everything
The real test for a simulation is to fit two
luminosity functions at two different redshifts
simultaneously!
Free parameter Star Formation Efficiency
z 4
z 6
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Reionization?
P
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Luminosity Functions
P
z 4
z 6
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Balancing the Books
P
(Bunker et al. 2004)
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Conclusions

• Simulations of reionization are consistent with
  the high
• value of SFR at z6 (0.02 M8/Mpc3/yr).
• Simulations are not consistent with the low
  value
• (0.005 M8/Mpc3/yr).
• Our simulations have barely enough resolution to
  make this
• claim. They need to be confirmed by better
  ones.

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The End
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Title