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Marta Gavilán Bouzas Mercedes Mollá Lorente

Gas and Metalliciy in Dwarf Galaxies. Marta Gavilán Bouzas Mercedes Mollá Lorente. Estallidos IV, Granada 2-04-07. What are we looking for?. We are looking for some signs to know if dwarf galaxies lose some of their gas or not. How do we looking for it?.

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Marta Gavilán Bouzas Mercedes Mollá Lorente

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  1. Gas and Metalliciy in Dwarf Galaxies Marta Gavilán Bouzas Mercedes Mollá Lorente Estallidos IV, Granada 2-04-07

  2. What are we looking for? • We are looking for some signs to know if dwarf galaxies lose some of their gas or not. How do we looking for it? • Our aim is to have a large amount of model results (in an autoconsistent way) to obtain the maximum number of clues. • We analized: gas content, metallicity and photometry and compare them with observations.

  3. A short review Galactic Chemical Evolution Model Grid of models

  4. Galactic Chemical Evolution Model The free parameters are: • the collapse time: Tcol • the efficiency in forming molecular clouds: em • the efficiency in transform the clouds into stars: eh The SFR is a RESULT not an INPUT There are no STAR BURSTS: the star forming process is continuous, but not constant

  5. Grid of Models Mass interval: Six values From 8 106 M¤ to 3 109M¤ Collapse time: Four values From 8 Gyr to 60 Gyr Star Formation Parameters: Four values S, M, L, XL TOTAL GRID: 96 Models

  6. SFR HISTORIES Lower Tcol and Higher em and ehè e = 0.9 Higher Tcol and Lower em and ehè e = 0.1 Efficiency=0.88 Efficiency=0.40 Efficiency=0.17

  7. Effective Yield p = 0.0034 The gas fraction estimation

  8. Oxygen Effective Yield

  9. Models Garnett 02 DwGx Garnett 02 S Van Zee 06 Oxygen Abundance Ln(1/m) Tot

  10. e = 0.40 e = 0.30 e = 0.24 e = 0.21 IIZw70 Kherig and col 2007

  11. Other observations What's happening?

  12. CONCLUSIONS • Our models present an effective yield without gas outflow according with most observations. • The models with high efficiency give too much high abundances. It is possible that they do not match with any observations. • In the case of IIZw70 we reproduce the SFR and the (O/H) value with no star burst . • …but the gas content needs additional explanation.

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