Anthony Aguirre

Professor Aguirre's astrophysics work has focused on numerically modeling enrichment of the intergalactic medium with metals and dust using numerical and semi-analytic calculations, and in analyzing QSO spectra to assess the observed metallicity of the IGM at all redshifts.

David Koo

Faint surveys of galaxies and active galactic nuclei (AGN) continue to be the primary focus of my research in observational cosmology. Besides using the Keck Telescopes to obtain deep spectroscopic surveys (e.g., DEEP2 & DEEP3) of the distant universe, my research also exploits the exquisite optical and near-infrared images from the Hubble Space Telescope (e.g. CANDELS) as well as complementary panchromatic (multiwavelength) imaging ranging from the X-ray using Chandra in space to the radio using the VLA from the ground (see AEGIS program). The science goals are to answer the basic questions of 1) how did galaxies acquire their stars, gas properties, dust, and morphologies? 2) what has been and explains their evolution in star formation, supermassive black hole growth, infall and outflow of gas, chemical abundances, and development and assembly of galactic structures such as bulges, disks, bars, clumps, and halos? and 3) can we explain what we observe with the most advanced theoretical simulations?

Mark Krumholz

Professor Krumholz's research focuses on star formation and the interstellar medium. The big questions he hopes to answer are what sets the global rate of star formation in gas clouds and galaxies? What determines the mass distribution of newly-formed stars? What processes control the formation of the most massive stars, which are the dominant source of luminosity in the universe? How long do star-forming clouds live, and what ultimately destroys them? He tries to answer these questions using a mixture of analytic investigations and numerical simulations

Doug Lin

Professor Lin's research interests include studies of star formation, the ISM of dwarf galaxies, and stellar accretion disks.

Piero Madau

Professor Madau's research focuses on theoretical astrophysics and cosmology. Specific topics within these broad areas are: the physics of the intergalactic medium, first light and the dawn of galaxies, high-energy radiation backgrounds, the formation and evolution of massive black holes, the cosmic history of star formation. Other recent interests include the "Via Lactea Project", a suite of extremely high-resolution simulations of the assembly of the dark matter halo of the Milky Way.

Bill Mathews

Emeritus Professor Mathews has worked on many problems involving the dynamics and physics of the ISM, quasar clouds and hot gas in galaxy clusters. In recent years he has studied AGN feedback in galaxy groups and clusters involving gas dynamics, cosmic rays, and dust cooling.

Joel Primack

Professor Primack works on simulating the large scale structure of the universe (including running and analyzing simulations like Bolshoi and Bolshoi-Planck) and the evolution of galaxies based on ΛCDM, and comparing these simulations with observations, especially from CANDELS. He develops semi-analytic models (SAMs) of the entire evolving galaxy population and compare with observations. He co-leads the Assembling Galaxies of Resolved Anatomy (AGORA) international collaboration to compare high-resolution hydrodynamic galaxy simulations, and he is developing analysis and visualization tools for AGORA with support from the University of California High-Performance AstroComputing Center (UC-HiPACC), which he directs. He also studies the extragalactic background light (EBL, all the radiation emitted by galaxies from the UV to the far-IR), both by calculating the EBL from SAMs and directly from observations, and also by using attenuation of high-energy gamma rays to measure the EBL.

J. Xavier Prochaska

Professor Prochaska's research examines the nature of gas both within and outside of galaxies, primarily during the first few billion years of the universe. The analysis relies on high resolution spectroscopy of distant, intrinsically bright sources (quasars, gamma-ray bursts). In this manner, we use the absence of light to study the metallicity, molecular fraction, depletion, ionization state, and velocity fields of gas in the young universe.

Enrico Ramirez-Ruiz

Professor Ramirez-Ruiz's research focuses on the violent universe with an emphasis on stellar explosions, gamma-ray bursts and accretion phenomena. I am particularly interested in understanding the physical processes that govern accretion onto relativistic objects such as black holes and neutron stars.


Zheng Cai

Dr. Cai is an IMPS fellow. He develops the novel technique to pinpoint the most massive proto-clusters at z=2-3, by utilizing intergalactic neutral hydrogen absorption and quasar groups. In addition, he is leading a number of other projects in high-redshift galaxies and IGM, including the studies of the intergalactic medium in emission, the early metal enrichment of IGM at z=4-6; constraining the Population III stars in galaxies at z=7; and probing the quasar host galaxies at z=2-3.

Ryan Cooke

Dr. Cooke is a Hubble Fellow at IMPS. He is primarily interested in Big Bang Nucleosynthesis, and the properties of the first stars and galaxies. His other current research interests include quasar absorption line systems, damped Lyman-alpha systems, stellar nucleosynthesis and Reionization.

Marcel Neeleman

Dr. Neeleman is an IMPS fellow.

Nicolas Tejos

Dr. Tejos is an IMPS Fellow working on the connection between the intergalactic medium (IGM) and galaxies. He is mainly focused on how this relationship depends on large-scale environment and cosmic time. In order to gather statistical samples of intergalactic material and galaxies, he mainly uses spectroscopy on telescopes such as HST, Keck, VLT, Gemini, Magellan among others. He is also interested in the use of gamma-ray bursts (GRBs) as background sources to observe the IGM, as a complement to the quasar (QSO) absorption line technique.

Jessica Werk

Dr. Werk is a Hubble Fellow at IMPS. Her interests lie in the extended, gaseous regions of galaxies, and how this gas relates to the gas flows that dominate galaxy formation and evolution. Her focus has been on the circumgalactic medium, which represents the largest baryonic component of a galaxy in both spatial extent and mass. She is an observer with expertise in optical and UV spectroscopy and photometry, who has had experience observing at nearly all wavelengths at many space and ground-based telescopes across the world.

Graduate Students

John Forbes

John Forbes is a PhD student at IMPS. His research currently focuses on the movement of baryons in and around galaxies.

Nathan Goldbaum

Caitlin Johnson

Caitlin Johnson is a graduate student at IMPS. Her research interests include extragalactic very high energy astrophysics and the extragalactic background light. By using a combination of instruments and wavelengths, she studies the processes occurring in AGN jets and how the gamma-ray emission propagates through the universe.

Marie Wingyee Lau

Marie Wingyee Lau is a graduate student at IMPS. Her first project with Professor Prochaska involved using spectroscopy of quasar pairs to study the physics of the circumgalactic medium. She is interested in cosmology or large scale structure initiated research.

Camille Leibler

Anna Rosen

Anna Rosen is a graduate student at IMPS. Her research interests are in the formation of massive star clusters and how the energy and momentum injected by the most massive stars in these clusters—stellar feedback—can potentially eject material from their natal cloud thereby, limiting how much gas will be turned into stars and controling the dynamics of HII regions. The types of feedback mechanisms she focuses on are stellar winds and stellar radiation.

Hassen Yesuf

Hassen Yesuf is a graduate student at IMPS. His interested in studying galaxy quenching processes that transform blue galaxies to red and dead galaxies. He has worked on AGN feedback in post-starburst galaxies and he is currently working on outflows/inflows in high redshift galaxies using deep keck spectroscopic surveys (DEEP3 & HALO7D) and optical and near-infrared images from the Hubble Space Telescope (in AEGIS & CANDELS fields).

Undergraduate Students

Brandon Day

Brandon Day is an undergraduate student working with Ryan Cooke on Lyα deforestation in an attempt to decode and extract precious information regarding the temperature of the IGM, deuterium abundances, neutral baryon distribution, and other factors of cosmology.

Alix Feinsod

Alix Feinsod is an undergraduate student doing research with Professor Prochaska. She is working on developing software to analyze lyman-alpha emission and absorption lines from high redshift galaxies.

Christian Millan

Christian Millan is an undergraduate student doing research with Professor Prochaska and Dr. Tejos. He is working on finding ways to define large-scale structures using the outputs of the cosmological N-body simulation, Bolshoi.

Visitor Scientists

B-G Andersson

Dr. Andersson is the Science Operations Manager and a senior scientist with the SOFIA project. His main research interests focus on observations of interstellar polarization, specifically with the aim of understanding the physical mechanisms behind interstellar dust grain alignment. He also works on high-resolution spectroscopy, using UV to radio wavelengths, with a goal of understanding the physics and chemistry of the transition between the dense and diffuse phases of the ISM.

Joseph Hennawi

Dr. Hennawi, now a research group leader at MPIA, leads several IGM programs related to spectroscopy of quasar pairs. He is a close collaborator of Professor Prochaska and a regular visitor of IMPS at UCSC.

Akio Inoue

Professor Inoue is an associate professor at College of General Education, Osaka Sangyo University, Japan. His research interests cover the cosmic reionization and intergalactic medium, galaxy formation and evolution, and dust in galaxies. He has also published few papers on dust in protoplanetary disks. He is a short-term scholar at UCSC during the fall and winter quarters in 2014/2015.

John O'Meara

Professor O'Meara is an assistant professor of Physics at Saint Michael's College. His research interests include statistics of the Lyman alpha forest, Lyman limit and damped Lyman alpha systems, the IGM/galaxy interface, and observational tests of Big Bang Nucleosynthesis models using the D/H ratio.

Todd Tripp

Professor Tripp is a close collaborator of Professor Prochaska and a visitor of IMPS at UCSC.

Former Members

Serena Bertone

Current position: Tele-communications industry (Germany)

Sebastiano Cantalupo

Current position: Research Team Leader ("Obserassistent") at ETH Zurich

Kathy Cooksey

Current position: Assistant Professor of Physics & Astronomy, University of Hawai'i, Hilo

Michele Fumagalli

Current position: Lecturer, Durham University, UK

Amy Furniss

Current position: Postdoc, Stanford Univeristy

Jason Kalirai

Current position: Staff Scientist, STScI

Kyle Kaplan

Current position: PhD student, U. Texas

Kate Rubin

Current position: Clay Fellow, Harvard University

Sijing Shen

Current position: Postdoctoral Fellow, Cambridge University

Robert da Silva

Current position: Data scientist, Bay Area

Gabor Worseck

Current position: Postdoc, MPIA