Are the most metal-poor galaxies young?
2007 (English)In: Galaxy Evolution Across the Hubble Time, 2007Conference paper (Other (popular science, discussion, etc.))
We review the possibility that metallicity could provide a diagnostic for the age of a galaxy, hence that the most metal-poor star forming galaxies in the local universe may be genuinely young. Indeed, observational evidence for downsizing shows the average age of the stars in a galaxy to decrease with decreasing mass and metallicity. However, we conclude both from observational and theoretical viewpoints that metallicity is not an arrow of time. Consequently the most metal poor galaxies of our local universe are not necessarily young. Current observations suggest that an old stellar population is present in all metal-poor galaxies, although a couple of cases, e.g. IZw18, remain under debate. Further observations with more sensitive equipment should settle this question in the coming years.
Place, publisher, year, edition, pages
IdentifiersURN: urn:nbn:se:su:diva-11266DOI: doi:10.1017/S1743921306005060OAI: oai:DiVA.org:su-11266DiVA: diva2:177785