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| Paper: |
Evolution of the Milky Way: Some Open Issues for Gaia |
| Volume: |
458, Galactic Archaeology: Near-Field Cosmology and the Formation of the Milky Way |
| Page: |
147 |
| Authors: |
Gilmore, G. |
| Abstract: |
Chemical element distribution functions provide essential information
to develop our understanding of galaxy formation and evolutionary
processes. Current determination of the [Fe/H] and elemental abundance
distribution functions of representative samples of the main stellar
populations is surprisingly limited - most observational focus is on
either the very local or the very extreme. One robust result is
however the extremely small scatter in element ratios,
especially [α/Fe], about what are also very small
amplitude trends, over the whole observed range –4 ≤ [Fe/H]
≤ +0.3. Another is that the thin disc really does lack a
significant metal-poor tail: the G-dwarf problem is still
providing us with information. Small elemental abundance scatter
requires extremely efficient ISM mixing on large scales at all
times. At face value this is not consistent with significant merger or
accretion events being an important aspect of Galaxy evolution,
contrary to expectation. Future progress in our understanding is
expected to be rapid, with the launch of Gaia in 2013, and the
beginning of large dedicated spectroscopic surveys, to complement
Gaia, and to define the typical. Subaru, with an appropriate
multi-object spectrograph, could become the northern hemisphere leader
in this exciting scientific opportunity. |
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