20100929_J.Yin

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					The Chemical evolution
     of late-type
   dwarf galaxies
        Yin Jun
       2010.09.29
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…
Model description
  The Chemical
Evolution of IC10

    (arXiv:1005.3500)
   The Chemical
Evolution of Dwarf
Irregular and BCGs

    (submitted to A&A)
 Observations

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

Observations II.
     abundance ratios   Y-Z relation
 Model results

Model without wind

  μ-Z & Y-Z relations   M-Z relation
   Model results

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




                                        Y-Z rel.
 Model results

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

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




                                      Y-Z rel.
   Model results

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




                                       Y-Z rel.
 Model results

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

Best models I.
 Model results

Best models II.
abundance ratios
 Model results

Best models III.
 Model results

Best models IV.
 abundance ratios
     (DLAs)
 Model results

Models with continuous SF
    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.
The nature of Long-GRB
  host galaxies from
 chemical abundances

       (arXiv:1007.4435)
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?
 Model results

Evolution of metallicity I.
         SFE=1                  SFE=0.05




          SFE=0.1               SFE=0.01
           Irregular galaxies
 Model results

Evolution of metallicity II.




           Spiral galaxy
 Model results

Abundance ratios
 Model results

Enrichment history
 Model results

SN I b/c rate
  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
Thank you!
  Discussion:
Work in Future…

				
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