Collaborative Research: CDS&E: Constraining the uncertain physics of galaxy formation: cosmic rays, black holes, and beyond

Computer simulations of galaxy formation are powerful tools to help understand, test, and predict the observed properties of galaxies in the local and extremely distant Universe. Given the large number of sensitive wide-area galaxy surveys that have recently started (or are soon to be underway) there is a critical need for simulations that model the formation and evolution of galaxies with the highest accuracy.

The proposed research will build upon the group’s earlier transformative galaxy simulations by adding the effects of gas accretion onto massive black holes, extremely high energy atomic nuclei (cosmic rays), and magnetic fields. These efforts will additionally train graduate and undergraduate students, mentor area high school students, and produce animations for public shows. The team will continue an educational program for prison inmates.

This research represents the further development of a project started several years ago by the FIRE (Feedback in Realistic Environments) collaboration to create state-of-the-art hydrodynamic simulations of galaxy formation and evolution that included a detailed treatment of “feedback” from massive stars and supernovae. That work successfully reproduced a wide range of observed galaxy properties – masses, chemical abundances trends, and scaling relations – for dwarf galaxies up to approximately Milky Way sized (L*) systems.

For more massive galaxies, an accurate treatment of the energy injected by rapidly accreting massive black holes (i.e., active galactic nuclei; AGN) is required. This is one of the primary updates to the original FIRE simulation code proposed here. Other potentially important processes, including magnetic fields and cosmic rays, and a new framework to track chemical abundances are to be implemented as well.

These promise to result in new galaxy simulations with parsec-scale resolution that are more accurate and that allow predictions (i.e., “forward modeling”) for a wide range of physical phenomena, including resolved radio and gamma-ray emission, cosmic ray spectra, Faraday rotation in and around galaxies, the Sunyaev-Zeldovich effect, and the dynamics of the circum-galactic medium. The FIRE team will make publicly available to the scientific community new modules for the GIZMO simulation code developed as part of this work, as well as data products from the project.

In the area of Broader Impacts this project will support four graduate students, a dozen undergraduate students, and a number of high-school students involved in creating scientific animations. The team will also engage inmates in educational activities via a partnership with the Stateville Correctional Center.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.