The Chemical evolution of late-type dwarf galaxies

1. The Chemical evolution of late-typedwarf galaxies Yin Jun 2010.09.29

2. Content • Model description • The chemical evolution of IC10 (arXiv: 1005.3500) • The chemical evolution of dwarf irregular and blue compact galaxies (submitted to A&A) • The nature of Long-GRB host galaxies from chemical abundances(arXiv: 1007.4435) • Discussion:work in future…

3. Model description

5. The Chemical Evolution of IC10 (arXiv:1005.3500)

6. The Chemical Evolution of Dwarf Irregular and BCGs (submitted to A&A)

7. Observations Observations I. M-Z relation μ-Z relation

8. Observations Observations II. abundance ratios Y-Z relation

9. Model results Model without wind M-Z relation μ-Z & Y-Z relations

10. Model results Model with normal wind I. – diff. λ abundance ratios μ-Z rel. Y-Z rel.

11. Model results Model with normal wind II. M-Z relation

12. Model results Model with metal-enhanced wind I. – diff. w abundance ratios μ-Z rel. Y-Z rel.

13. Model results Model with metal-enhanced wind II. – diff. λ abundance ratios μ-Z rel. μ-Z rel. Y-Z rel. Y-Z rel.

14. Model results Model with metal-enhanced wind III. M-Z relation

15. Model results Best models I.

16. Model results Best models II. abundance ratios

17. Model results Best models III.

18. Model results Best models IV. abundance ratios (DLAs)

19. Model results Models with continuous SF

20. Summary Summary We studied the chemical evolution of late-type dwarfs: • SF scenario: • Bursting SF:n < ~10, ε~0.5 Gyr-1; • Continuous SF: • mild SF (ε≤0.01 Gyr-1, d~13Gyr) should not be the majority; • higher SFE (0.01~0.2 Gyr-1) and shorter d (4~8 Gyr) are acceptable. • Galactic winds are necessary • normal wind: lose too much gas,rejected; • metal-enhanced wind: preferred, λmw is lower than dSphs’. • M-Z relation: • no wind: increasing amount of SF (n, ε ,d) with galactic mass; • normal wind: increasing λw , unless gas infall continuously; • metal-enhanced wind: constant λmw! • DLAs could be the progenitors of local dIrrs and BCDs.

21. The nature of Long-GRB host galaxies from chemical abundances (arXiv:1007.4435)

22. Questions • Which galaxies are the hosts of LGRBs? • Are the LGRB systems (LGRB associated DLA systems at high redshift and LGRB host galaxies at low redshift) belonging to an evolutionary sequence, in other words, are they the same objects at low and high redshift just seen in different phases of their evolution?

23. Model results Evolution of metallicity I. SFE=1 SFE=0.05 SFE=0.1 SFE=0.01 Irregular galaxies

24. Model results Evolution of metallicity II. Spiral galaxy

25. Model results Abundance ratios

26. Model results Enrichment history

27. Model results SN I b/c rate

28. Summary Summary Which galaxies are the hosts of LGRBs? • Irregular gal. – slowly evolving, SFE=0.05 - 0.1, possible • Spiral gal. – too high absolute abundances, No; but outermost regions, possible; • Elliptical gal. – quick enrichment, passive evolution, No. Are the LGRB-DLAs and local LGRB host galaxies belonging to an evolutionary sequence? • If they are, they should be irregulars

29. Thank you!

30. Discussion: Work in Future…