Anthony N Aguirre

TitleAssociate Professor
DivisionAcademic Affairs
DepartmentPhysics Department
AffiliationsAstronomy & Astrophysics Department
Web Site Web Page
Office325 Isb
Campus Mail StopPhysics Department
Mail1156 High Street
Santa Cruz, CA
picture of Anthony N Aguirre

Research Interests

My current research falls in three main categories. The first and probably largest is the study of cosmological inflation and eternal inflation. Inflation is a compelling component of the standard model of cosmology with considerable observational success. Eternal inflation, which is generic in inflation models, describes a situation where inflation goes on forever, ending only locally and thus continually creating “pockets” or “bubbles” of non-inflation that might have diverse properties and one of which might contain our observable universe. (See here for a review article of mine.) My current research, which assesses whether collisions between expanding “bubble universes” could leave an observable imprint on the cosmic microwave background or other cosmological observables.

A second set of research focuses on: heavy-element enrichment of the intergalactic medium. Heavy elements, such assilicon, oxygen, and carbon (or “metals” is astro-parlance), are formed inside stars, which are located in galaxies. Yet, these elements are also observed in the "intergalactic medium" between galaxies. These metals may ultimately provide a "fossil record" for star and galaxy formation during the very early universe. I have tackled these issues using theory (such as computer simulations to test various ejection scenarios) and observation (analyzing quasar spectra to see how the elements are distributed outside of galaxies). A major current project seeks to compare a new set of top-notch cosmological simulations to the observations of metal enrichment, to test and constrain these simulations and the physics of metal-ejection that they implement. A second project will use the observed abundances in conjunction with modeling of the intergalactic medium, to test and constrain models of the “ultraviolet background” at high-redshift, which is a combination of radiation from all stars and quasars, and provides a constraint on the history of star and galaxy formation, as well as a crucial input into efforts to model physical cosmology and galaxy formation.

The third category is "other": I’ve also worked on a number of Past projects/topics, including

Dark matter and population III stars

Intergalactic dust

Radically different cosmologies which don’t turn out to be true, but might still be interesting

Black holes (possibly exploding ones)

How to make a universe in your basement (or not)

Can modified gravity substitute for dark matter?