Staff Members

Andrew Benson

Andrew Benson is a Staff Scientist at the Carnegie Observatories. His research program is focused on understanding the nature of dark matter and the process of galaxy formation, with a particular emphasis on formulating a coherent picture of the many different aspects of these problems. He has developed a model of dark matter and galaxy formation physics, Galacticus, which is available to the community as an open source project. The approach blends both analytic understanding and significant number-crunching that utilizes both in-house and external compute clusters.

Juna Kollmeier

Juna Kollmeier is the Director of SDSS-V, an unprecedented panoptic spectroscopic survey that will yield optical and infrared spectra of over 6 million objects. Her research is primary focused on the emergence of structure in the universe. She combines cosmological hydrodynamic simulations and analytic theory to figure out how the tiny fluctuations in density that were present when the universe was only 300,000 years old, become the galaxies and black holes that we see now, after 14 billion years of cosmic evolution. 

Anthony Piro

Anthony Piro is interested in a wide range of topics in theoretical astrophysics, including compact objects, astrophysical explosions, accretion flows, and stellar dynamics. His expertise is in nuclear physics, thermodynamics, condensed matter physics, General Relativity, and fluid and magnetohydrodynamics. He uses this background to predict new observational phenomena, as well as to understand the key underlying physical mechanisms responsible for current observations. He uses a combination of analytic and simple numerical models to build physical intuition for complex phenomena.

Current Postdocs

Lauren Anderson

Lauren Anderson works on applying computational data analysis techniques to interesting astronomy problems. She combines data-driven models with physical models to harness both flexibility and interpretability. She also works on making models computationally tractable such that the model parameter space can be explored efficiently. Currently, Anderson is building a 3D dust map of the Milky Way galaxy using scalable Gaussian processes. She is also interested in falsifying dark matter models using stellar streams around the Milky Way galaxy observed by Gaia.

Xiaolong Du

Xiaolong Du is a postdoctoral associate at the Carnegie Observatories. His work focuses on cosmological structure formation in different dark matter models and on constraints on these models from gravitational effects such as substructure lensing. Using idealized numerical simulations and semi-analytic models, he tries to find an accurate, but fast, way to study the behaviors of dark matter on sub-galactic scales, where different dark matter candidates may behave very differently.

Andrew Emerick

Andrew Emerick joined the Carnegie Observatories in 2019 as a Pasadena Fellow, a joint postdoctoral position between Carnegie and Caltech. He is broadly interested in galactic chemical evolution and the role of stellar feedback in driving galactic evolution. Emerick focuses on developing, running, and analyzing detailed hydrodynamics simulations of individual galaxies with particular interest in the physics that give rise to the stellar abundance patterns seen today in nearby dwarf galaxies. He is an active developer to multiple astrophysical codes and libraries, including Enzo, Enzo-E, Grackle, and GIZMO, as a member of the FIRE collaboration.

Ylva Götberg

Ylva Götberg is the Alvin E. Nashman Fellow in theoretical astrophysics. Her research focuses on interacting binary stars and how they impact on their surroundings. She uses computational tools to understand how interacting binaries, for example, affect the surrounding nebulae or contribute to cosmic reionization and to predict new classes of gravitational wave sources.

Fangzhou Jiang

Fangzhou Jiang is a postdoc at the Carnegie Observatories and California Institute of Technology, specializing in the theory of galaxy formation and evolution. He studies the interplay between galaxies and the dark-matter halos that they host using semi-analytic models and cosmological simulations, with an emphasis on halo substructure, galaxy morphology, and the properties of dwarf galaxies and satellite galaxies as testbeds of cosmology and feedback prescriptions. 

Kyle Kremer

Kyle Kremer joined the Carnegie Observatories in 2020 as an NSF Fellow. He develops N-body simulations of dense stellar clusters, with a particular focus upon the dynamical formation and evolution of black hole binaries within these environments. His primary current interest is in applications to gravitational wave astrophysics and high-energy transients.

Lina Necib

Lina Necib joined the Carnegie Observatories in 2020. She works on using Galactic dynamics to understand the properties of dark matter. She has combined cosmological simulations, stellar catalogs, machine learning techniques, and a background of particle physics to build the first map of dark matter in the Milky Way.  

Abigail Polin

Abigail Polin is a postdoctoral fellow joint between the Carnegie Observatories and Caltech. She is interested in supernovae and other astrophysical transients.  She models these events using hydrodynamical and radiative transport simulations, and makes testable predictions that are compared to light curves and spectra of observed supernovae. She is also heavily involved in the interpretation of observed transients, especially sub-Chandrasekhar Type Ia supernovae and Calcium-rich transients.


David Gonzalez-Dysinger

David Gonzalez-Dysinger is a graduate student at the University of Southern California, currently working with Andrew Benson to study the effects of dark matter particle physics on the abundance and distribution of gravitationally bound structure in the dark sector. The goal of his work is to understand how gravitational lensing observations will constrain dark matter particle physics.

Annastasia Haynie

Annastasia Haynie is a graduate student at University of Southern California and works at the LouCarnegie Observatories as a USC-Carnegie Fellow. She is broadly interested in astrophysical explosions and works with Anthony Piro on numerically modeling the shock breakout signal of core-collapse supernovae. At USC, she is also a part of Vera Gluscevic's Cosmolab group, the President of the Women in Physics organization, Vice President of the Graduate Association for Students in Physics, and the Physics Department Liaison for the Women in Science and Engineering organization.

Armen Tokadjian

Armen Tokadjian is a third year graduate student at the University of Southern California and works with Anthony Piro as a USC-Carnegie Fellow. His research is focused on the dynamics of star-planet-moon systems and the influence of tides on their evolution. He is especially interested in prospects for the habitability of extrasolar worlds.

Former Postdocs

TJ Cox (2009-12) now Data Scientist at Voxer

Selma de Mink (2013-14) now Associate Professor in Astrophysics at Harvard University

Andrew Wetzel (2013-17) now Assistant Professor of Physics at the University of California, Davis

Stephanie Tonnesen (2014-17) now Associate Research Scientist at the Center for Computational Astrophysics at the Flatiron Institute

Jennifer van Saders (2014-17) now Assistant Professor at the Institute for Astronomy at University of Hawaii

Yu Lu (2015-18) now Senior Data Scientist at Lam Research Corporation

Stefano Pasetto (2016-2018) now Research Scientist at Moffitt Cancer Center and Research Institute

Coral Wheeler (2020) now Assistant Professor in the Department of Physics and Astronomy at Cal Poly Pomona