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 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

arXiv e-prints 2026

Correlation between baryonic process and galaxy assembly bias

Xiao, Zilan, A. Benson, et al.

This study establishes a direct link between baryonic processes and galaxy assembly bias, revealing that gas cooling and stellar feedback are key factors influencing galaxy clustering. The findings offer valuable insights for improving galaxy survey models and understanding the role of baryonic physics in galaxy formation.

ADS · arXiv · DOI

arXiv e-prints 2026

The pre-infall bias of subhalos

Delos, M. Sten, A. Benson, et al.

This study reveals that dark matter halos set to merge with larger hosts are inherently more massive and concentrated than typical halos of the same mass, even before they begin to merge. This finding enhances the understanding of halo formation and evolution in the context of dark energy's influence on structure growth.

ADS · arXiv · DOI

arXiv e-prints 2026

The Sensitivity of Substructure Lensing to SIDM Core-collapse Model Variation

Mace, Charlie, A. Benson, et al.

This study highlights the sensitivity of gravitational lensing to variations in the modeling of core-collapse in self-interacting dark matter subhalos. The findings indicate that small changes in halo evolution can significantly affect lensing predictions, which is crucial for future analyses in understanding dark matter.

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 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

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 →