Theoretical Astrophysicist · Carnegie Observatories

Andrew Benson

I am a Staff Scientist at the Carnegie Observatories. My research is focused on understanding the nature of dark matter and the process of galaxy formation — combining analytic models, numerical simulations, and large astronomical surveys.

Email ADS Library GitHub ORCID

Research focus

What I work on

Three threads tie my research together: building a coherent theoretical model of galaxy formation; constraining the microphysics of dark matter; and designing the synthetic universes that next-generation surveys need to interpret their data.

Galaxy formation

The Galacticus model

An open-source semi-analytic model of galaxy formation used to interpret observations across cosmic time.

Dark matter

Constraining dark matter microphysics

Using halo substructure, gravitational lensing, and dwarf galaxies to test warm, self-interacting, and other non-CDM models.

Surveys

Synthetic skies for next-gen surveys

Building galaxy mocks for the Roman GRS Project Infrastructure Team and the NASA Open Universe initiative.

Recent work

Selected recent papers

These cards are rebuilt automatically from my NASA ADS library on a weekly schedule. Summaries and figures are generated from the paper itself.

Figure from Calibrating the self-interacting dark matter gravothermal catastrophe with <inline-formula><mml:math><mml:mi>N</mml:mi></mml:math></inline-formula>-body simulations

Physical Review D 2026

Calibrating the self-interacting dark matter gravothermal catastrophe with N-body simulations

Mace, Charlie, A. Benson, et al.

This study calibrates the heat transfer parameter in self-interacting dark matter models using advanced simulations, revealing that this parameter remains consistent across various conditions. The findings provide a new effective model for predicting dark matter halo evolution, streamlining comparisons with simulations and enhancing our understanding of dark matter density profiles.

ADS · arXiv · DOI

Figure from Connection between Galaxy Morphology and Dark-matter Halo Structure. II. Predicting Disk Structure from Dark-matter Halo Properties

The Astrophysical Journal 2026

Connection between Galaxy Morphology and Dark-matter Halo Structure. II. Predicting Disk Structure from Dark-matter Halo Properties

Liang, Jinning, A. Benson, et al.

This study reveals that the structure of galactic disks can be accurately predicted from the properties of their dark-matter halos, highlighting the influence of baryonic processes on halo characteristics. The findings provide valuable empirical relations for modeling galaxy structures, particularly emphasizing the differences in predictions based on halo mass and redshift.

ADS · arXiv · DOI

The Open Journal of Astrophysics 2026

DiffstarPop: A generative physical model of galaxy star formation history

Alarcon, Alex, A. Benson, et al.

DiffstarPop is a new model that accurately simulates the star formation histories of galaxies by linking them to the mass assembly of dark matter halos. This tool can efficiently generate large catalogs of synthetic galaxies, enhancing our understanding of galaxy formation and evolution in cosmological simulations.

ADS · arXiv · DOI

Monthly Notices of the Royal Astronomical Society 2026

Advancing stellar streams as a dark matter probe ─ I: effects of subhalo density profile

Menker, Paul, A. Benson, et al.

This research develops a more accurate model for predicting gaps in stellar streams caused by dark matter substructures, finding that the number of expected gaps is significantly higher than previously estimated. This advancement enhances the potential of stellar streams as tools for probing dark matter properties.

ADS · arXiv · DOI

The Astrophysical Journal 2026

Stellar Mass Growth in the First Galaxies: Theory and Observation

Dressler, Alan, A. Benson, et al.

This study finds strong agreement between observed stellar mass growth in early galaxies and predictions from the GALACTICUS model, highlighting the importance of stellar mass as a fundamental measure in galaxy formation. The results suggest that significant in situ growth and mergers contributed to stellar mass increases during the early universe, challenging previous claims about the dominance of star formation bursts.

ADS · arXiv · DOI

Monthly Notices of the Royal Astronomical Society 2026

The THESAN project: environmental drivers of Local Group reionization

Zhao, Yu, A. Benson, et al.

The THESAN project reveals that the timing of cosmic reionization in Local Group analogues is significantly influenced by their surrounding environment, with denser regions ionizing earlier. This research enhances understanding of how large-scale structures affect reionization, providing insights into the early histories of galaxies like the Milky Way.

ADS · arXiv · DOI

See all recent papers →

Open source

Galacticus

Most of my modeling work happens inside Galacticus, an open-source semi-analytic model of galaxy formation that I wrote and continue to develop. It's used by groups around the world to study dark matter, galaxy evolution, and forecast observations for upcoming surveys. See the full software stack →