Article
The imprint of clump formation at high redshift - I. A disc alpha-abundance dichotomy
Authors
Adam J. Clarke, Victor P. Debattista, David L. Nidever, Sarah R. Loebman, Raymond C. Simons, Susan Kassin, Min Du, Melissa Ness, Deanne B. Fisher, Thomas R. Quinn, James Wadsley, Ken C. Freeman, Cristina C. Popescu
Publication
Monthly Notices of the Royal Astronomical Society
Abstract
The disc structure of the Milky Way is marked by a chemical dichotomy, with high-alpha and low-alpha abundance sequences, traditionally identified with the geometric thick and thin discs. This identification is aided by the old ages of the high-alpha stars, and lower average ages of the low-alpha ones. Recent large-scale surveys such as APOGEE have provided a wealth of data on this chemical structure, including showing that an identification of chemical and geometric thick discs is not exact, but the origin of the chemical dichotomy has remained unclear. Here we demonstrate that a dichotomy arises naturally if the early gas-rich disc fragments, leading to some fraction of the star formation occuring in clumps of the type observed in high-redshift galaxies. These clumps have high star formation rate density. They therefore enrich rapidly, moving from the low-alpha to the high-alpha sequence, while more distributed star formation produces the low-alpha sequence. We demonstrate that this model produces a chemically defined thick disc that has many of the properties of the Milky Way's thick disc. Because clump formation is common in high-redshift galaxies, we predict that chemical bimodalities are common in massive galaxies.
Links
How is this information collected?
This collection of Montana State authored publications is collected by the Library to highlight the achievements of Montana State researchers and more fully understand the research output of the University. They use a number of resources to pull together as complete a list as possible and understand that there may be publications that are missed. If you note the omission of a current publication or want to know more about the collection and display of this information email Leila Sterman.