Astronomy and Astrophysics – Astrophysics
Scientific paper
2008-11-14
Astronomy and Astrophysics
Astrophysics
10 pages, 7 figure, invited talk at IAU Symposim 258 "Ages of Stars"
Scientific paper
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.
Matteucci Francesca
Pipino Antonio
No associations
LandOfFree
The timescales of chemical enrichment in the Galaxy does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The timescales of chemical enrichment in the Galaxy, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The timescales of chemical enrichment in the Galaxy will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-10700