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Hansik Kim (UMelb) C. Power(ICRAR), S.Wyithe(UMelb), GALFORMers(ICC)

Physical processes Drive the Abundance and Clustering of Neutral Atomic Hydrogen in Galaxies in hierarchical galaxy formation model. Hansik Kim (UMelb) C. Power(ICRAR), S.Wyithe(UMelb), GALFORMers(ICC). hansikk@unimelb.edu.au. 01/12/2011 Workshop on East-Asian Collaboration for SKA. Outline.

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Hansik Kim (UMelb) C. Power(ICRAR), S.Wyithe(UMelb), GALFORMers(ICC)

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  1. Physical processesDrive the Abundance and Clustering of Neutral Atomic Hydrogen in Galaxiesin hierarchical galaxy formation model Hansik Kim (UMelb) C. Power(ICRAR), S.Wyithe(UMelb), GALFORMers(ICC) hansikk@unimelb.edu.au 01/12/2011 Workshop on East-Asian Collaboration for SKA

  2. Outline • Recipe of making Galaxy into the DM haloes. • Distribution of predicted galaxy samples and its implication. (Kim et al. 2010) • Feedbacks to Abundance and Clustering of Galaxies. • Summary.

  3. Semi-Analytic Galaxy Formation Model Properties of galaxy

  4. Semi-analytic model • Rapid exploration of the parameter space of galaxy formation physics. • Large, statically useful samples. • Wide range of properties, multi-wavebands. Baugh 2006

  5. Cole et al. 2000

  6. Distribution of Galaxies • Cold gas galaxies located in small mass of dark matter haloes. • Most of cold gas galaxies are central galaxies. Kim et al. 2011

  7. HI mass from the simulation • Cold Gas to HI mass. • Fixed H2/HI ratio (cf. Baugh et al. 2004) • Variable H2/HI ratio (cf. Obreschkow et al. 2009) • Self-consistent predictions (cf. Lagos et al. 2010)

  8. HIMF from self-consistent prediction Vcut=30km/s Zcut=10 4 times better resolution than Millennium Simulation. Thanks to Lagos

  9. Performance prediction for the next generation surveys. Cover 20000deg2 in 1 yr The forecast constrains on the dark energy equation of state Kim et al. 2011

  10. Abundance and Clusteringof Neutral Atomic Hydrogen in Galaxies • Feedback processes. Supernovae(SNe) feedback Active Galactic Nuclei(AGN) feedback Photo-ionization(PI) feedback Kim et al. 2011 (Preparation)

  11. SNe feedback • SNe feedback is effective in low mass galaxies. • SNe feedback is modelled in GALFORM as • Vhot=485km/s and ahot=3.2

  12. Changed overall range of LF.Changed intermediate of HIMF. Resolution Mass cut

  13. The Halo Occupation Distribution (HOD)is a parameter of the halo model of galaxy clustering. The halo model provides one view of the large scale structure of the universe as clumps of dark matter, while the HOD provides a view of how galactic matter is distributed within each of the dark matter clumps. The HOD is used to describe three related properties of the halo model: the probability distribution relating the mass of a dark matter halo to the number of galaxies that form within that halo; the distribution in space of galactic matter within a dark matter halo; the distribution of velocities of galactic matter relative to dark matter within a dark matter halo. Zehavi et al. 2010

  14. Clustering strength depends on the strength of SNe feedback

  15. AGN feedback • To understand the bright end of LF. • Suppress the cooling flows in massive haloes.

  16. AGN feedback leads changing bright end of LF & High mass end of HIMF

  17. Small effect on the clustering of HI galaxy

  18. PI feedback • Ionization of the IGM suppresses cooling onto dark matter haloes. • Vcut (the host halo’s circular velocity, 30km/s) • Zcut (redshift, 10) in GALFORM.

  19. Changed faint end of LF & low mass end of HIMF by PI feedback strength

  20. PI feedback give a huge difference to HI poor galaxy clustering

  21. Summary & Future works Future HI survey results can predicted by physically motivated semi-analytic model. Semi-analytic model makes useful Mocks for the next generation HI galaxy surveys. Abundance and Clustering of HI galaxies are changed by Feedbacks. HI galaxy survey is one of important tools to constrain the galaxy formation models. Morphological type dependence. Environment dependence. Self-consistent PI feedback. References Power, Baugh & Lacey (2010, MNRAS, 406, 43), Kim et al. (2011, MNRAS, 414, 2367) Lagos et al. (2011, MNRAS, 416, 1566), Lagos et al. (2011, accepted to MNRAS) Kim et al. (preparation)

  22. Active Galaxy Mock Galaxy Normal Galaxy Thank you!!

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