Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The timescales of chemical enrichment in the Galaxy   The time-scales of chemical enrichment are fundamental to understand the
evolution of abundances and abundance ratios in galaxies. In particular, the
time-scales for the enrichment by SNe II and SNe Ia are crucial in interpreting
the evolution of abundance ratios such as [alpha/Fe]. In fact, the
alpha-elements are produced mainly by SNe II on time-scales of the order of 3
to 30 Myr, whereas the Fe is mainly produced by SNe Ia on a larger range of
time-scales, going from 30 Myr to a Hubble time. This produces differences in
the [alpha/Fe] ratios at high and low redshift and it is known as "time-delay"
model. In this talk we review the most common progenitor models for SNe Ia and
the derived rates together with the effect of the star formation history on the
[alpha/Fe] versus [Fe/H] diagram in the Galaxy. From these diagrams we can
derive the timescale for the formation of the inner halo (roughly 2 Gyr), the
timescale for the formation of the local disk (roughly 7-8 Gyr) as well the
time-scales for the formation of the whole disk. These are functions of the
galactocentric distance and vary from 2-3 Gyr in the inner disk up to a Hubble
time in the outer disk (inside-out formation). Finally, the timescale for the
formation of the bulge is found to be no longer than 0.3 Gyr, similar to the
timescale for the formation of larger spheroids such as elliptical galaxies. We
show the time-delay model applied to galaxies of different morphological type,
identified by different star formation histories, and how it constrains
differing galaxy formation models.

32
The categories of this paper are: atom-ph
25
The categories of this paper are: patt-sol
9
The categories of this paper are: nlin
27
The categories of this paper are: comp-gas
4
The categories of this paper are: cond-mat
29
The categories of this paper are: funct-an
36
The categories of this paper are: cmp-lg
3
The categories of this paper are: physics
1
The categories of this paper are: cs
2
The categories of this paper are: math
0
The categories of this paper are: hep-ph
22
The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin
31
The categories of this paper are: ao-sci
28
The categories of this paper are: alg-geom
7
The categories of this paper are: hep-th