1. March 27, 2008 Milan Raicevic ICC, Durham University Studying the role of inhomogeneous reionization in galaxy formation with GALFORM and SimpleX Collaborators: Tom Theuns, Cedric Lacey, Wong Tam, John Helly, J.-P. Paardekooper Milan Raicevic

2. March 27, 2008 Milan Raicevic ICC, Durham University Motivation: 1) employ a detailed model of early galaxies as source of reionization 2) include photo-ionizing feedback from inhomogeneous reionization 3) follow the model to the present day 4) quickly explore the parameter space

3. March 27, 2008 Milan Raicevic ICC, Durham University Scheme: + a detailed semi-analytic galaxy formation and evolution model an efficient radiative transfer method

4. March 27, 2008 Milan Raicevic ICC, Durham University How the coupling works:

5. March 27, 2008 Milan Raicevic ICC, Durham University How the coupling works:

6. March 27, 2008 Milan Raicevic ICC, Durham University semi-analytic galaxy formation and evolution model Processes included in the model: – gas cooling, – star formation, supernova feedback, AGN feedback – galaxy mergers, – chemical enrichment, – stellar population evolution, – dust extinction and emission.

7. March 27, 2008 Milan Raicevic ICC, Durham University GALFORM models reproduce many z = 0 observables Baugh et al. 2005Bower et al. 2006

8. March 27, 2008 Milan Raicevic ICC, Durham University Halo ionizing luminosities in GALFORM

9. March 27, 2008 Milan Raicevic ICC, Durham University How is reionization modeled in GALFORM itself: zcut: global redshift at which the suppression of gas cooling in low mass halos is turned on vcut: maximum circular velocity of a halo that can be affected by photo-ionization feedback

10. March 27, 2008 Milan Raicevic ICC, Durham University Effect of zcut:

11. March 27, 2008 Milan Raicevic ICC, Durham University Effect of vcut:

12. March 27, 2008 Milan Raicevic ICC, Durham University Redshift evolution of the emissivity:

13. March 27, 2008 Milan Raicevic ICC, Durham University SF bursts due to galaxy mergers in Baugh et al. 2005:

14. March 27, 2008 Milan Raicevic ICC, Durham University Transports photon packets on an unstructured grid created to match the mean free path of the photons Independent from the number of sources very fast (due to precomputed photon paths)‏ version for this project:  OpenMP parallelized  sub-cell prescription for very optically thick cells  vertices selected directly from the N-body particles

15. March 27, 2008 Milan Raicevic ICC, Durham University SimpleX grid is adaptive by construction:

16. March 27, 2008 Milan Raicevic ICC, Durham University Full coupled run: 20 Mpc/h side box 512 3 DM particles 128 3 SimpleX RT grid min. halo mass: 8x10 7 M_sun

17. March 27, 2008 Milan Raicevic ICC, Durham University Result: reionization redshift for each halo

18. March 27, 2008 Milan Raicevic ICC, Durham University Effect of patchy reionization:

19. March 27, 2008 Milan Raicevic ICC, Durham University Effect of patchy reionization:

20. March 27, 2008 Milan Raicevic ICC, Durham University Effect of patchy reionization:

21. March 27, 2008 Milan Raicevic ICC, Durham University Effect of patchy reionization:

22. March 27, 2008 Milan Raicevic ICC, Durham University Stumbling blocks: We need a large, highly resolved DM simulation ran to z=0: We need a bigger machine for high resolution RT runs: Millenium 2: 100 Mpc/h box size ~ 2x10 8 M_sun/h minimum halo mass MPI version in the works a few potential large shared memory machines available

23. March 27, 2008 Milan Raicevic ICC, Durham University Conclusions / future work: including ionization heating as a parameter to galaxy formation model study the parameter space of reionization make 21cm signal predictions Lyα emitter correlation-functions running on the Aquarius simulation to study the fate of satellites during reionization