TAP Members

The TAP welcomes new faculty, postdoc, and student members. Member benefits include opportunities to participate in visitor program events, collaborative development of major funding proposals, events with colloquia speakers, and other ongoing TAP programs.

Theorists and theory students in the TAP member departments are strongly encouraged to participate in TAP Initiatives as these collaborations will be the source of future research directions and new funding proposals in addition to directing the TAP Visitor Program. In addition to theorists, experimentalists, and observers interested in expanding their research programs/proposals through collaborations with theorists are encouraged to apply for membership and participate in TAP Initiatives.

The aim is to expand UArizona’s strength in theoretical astrophysics and computational methods and build productive interdisciplinary collaborations across the member departments. To support this, membership is organized as follows:

TAP General Faculty:

Faculty in the Astronomy, Physics, or Planetary Sciences departments who lead research programs using theoretical and/or computational methods to study astronomical objects and/or astrophysical processes.

TAP Postdocs and Students:

Postdocs, graduate students, and undergraduate students who are working on research with a TAP General Faculty Member in Astronomy, Physics, and Planetary Sciences. TAP Students can apply for all program opportunities, including the annual Small Matching Grants and the TAP Student Research Prize.

TAP Partners in AST, LPL, and PHY:

Faculty, postdocs, or students from a TAP department participating in TAP Initiatives and interested in collaborative research efforts. 

TAP Partners in Other Units:

Faculty, postdocs, and students from other departments or external organizations.

Apply for TAP Membership:

New member applications are reviewed regularly. New members will receive a confirmation email with member level and benefits.

TAP New Member Application

Complete the short application to become a TAP member.

Current TAP Members

TAP General Faculty Members

Faculty in the Astronomy, Physics, or Planetary Sciences departments who lead research programs using theoretical and/or computational methods to study astronomical objects and/or astrophysical processes.


Erik Asphaug, Planetary Sciences
Travis Barman, Planetary Sciences
Peter Behroozi, Astronomy
Gurtina Besla, Astronomy
CK Chan, Astronomy
Kate Daniel, Astronomy
Keith Dienes, Physics
Tim Eifler, Astronomy
Federico Frashcetti, Planetary Sciences
Joe Giacalone, Planetary Sciences
Sam Gralla, Physics
Kris Klein, Planetary Sciences
Tommi Koskinen, Planetary Sciences
Kaitlin Kratter, Astronomy
Elisabeth Krause, Astronomy, Physics
Renu Malhotra, Planetary Sciences
Mark Marley, Planetary Sciences, Head
Isasmu Matsuyama, Planetary Sciences
Fulvio Melia, Physics
Vasileios Pachalidis, Astronomy
Eduardo Rozo, Physics
Ina Sarcevic, Physics
Jerry Sellwood, Astronomy
Shufang Su, Physics, Head
Andrew Youdin, Astronomy
Ann Zabludoff, Astronomy


TAP Postdoc and Student Members

Postdocs, graduate students, and undergrad students who are working on research with TAP general faculty members in Astronomy, Physics, and Planetary Sciences.

Joe Adamo, Astronomy, Graduate (Eifler)
Namya Baijal, Planetary Sciences, Graduate (Asphaug)
Jonah Barber, Physics, Graduate (Keith)
Supranta Bourah, Astronomy, Postdoc (Eifler, Rozo)
Haley Bowden, Astronomy, Graduate (Behroozi)
Jane Bright, Astronomy, Graduate (Paschalidis)
Teddy Broeren, Applied Math, Graduate (Klein)
Zarah Brown, Planetary Sciences, Graduate (Koskinen)
Joyce Byun, Astronomy, Graduate (Eifler)
Yangyang Cai, Physics, Graduate (Gralla)
Edgar Canizales, Physics, Graduate (Rozo)
Jose Daniel Castro Cisneros, Physics, Graduate (Malhotra)
Katherine Chamberlain, Astronomy, Graduate (Besla)
Eonho Chang, Applied Math, Graduate (Youdin)
Xiaohang Chen, Planetary Sciences, Graduate (Giacalone)
Emmanouil Drimalas, Physics, Graduate (Youdin)
Hayden Foote, Astronomy, Graduate (Besla)
Maria Gabriela Cota, Astronomy, Graduate (Krause )
Aaron Goldtooth, Astronomy, Graduate (Eifler)
Waverly Gorman, Physics, Graduate (Klein)
Elaheh Hayati, Physics, Graduate (Behroozi)
Yu-Hsiu Huang, Astronomy, Graduate (Krause )
Hung-Jin Huang, Astronomy, Postdoc (Eifler)
Lori Huseby, Planetary Sciences, Graduate (Barman)
Soley Hyman, Astronomy, Graduate (Daniel)
Chia-Lin Ko, Astronomy, Graduate (Zabludoff)
Yosuke Kobayashi, Astronomy, Postdoc (Krause)
Leonardo Krapp, Astronomy, Postdoc (Youdin, Kratter)
Rahul Kumar, Physics, Postdoc (Gralla)
Genevieve Kuo, Astronomy, Graduate (Pascucci)
Jingwei Liu, Physics, Graduate (Melia)
Kunal Lobo, Physics, Graduate (Gralla)
Vikram Manikantan, Astronomy, Graduate (Paschalidis)
Ian Matheson, Planetary Sciences, Graduate (Malhotra)
Robert Melikyan, Planetary Sciences, Graduate (Asphaug)
Annie Moore, Physics, Graduate (Krause)
Ashraf Moradi, Planetary Sciences, Postdoc (Giacalone)
Matthew Murphy, Astronomy, Graduate (Advisor)
Maria Mutz, Astronomy, Graduate (Paschalidis)
Mahdi Naseri, Astronomy, Graduate (Paschalidis)
Eleanor Puzzoni, Planetary Sciences, Postdoc (Federico)
Pranjal Rajendra Singh, Astronomy, Graduate (Krause)
Himansh Rathore, Astronomy, Graduate (Besla)
Paul Rogozenski, Physics, Graduate (Krause)
Thomas Routt, Astronomy, Graduate (Zabludoff)
Marc Rovira Navarro, Planetary Sciences, Graduate (Matsuyama)
Tanner Saadi, Physics, Graduate (Rozo)
Andres Salcedo, Astronomy, Postdoc (Krause, Rozo)
Niranjana Shankarappa, Physics, Graduate (Klein)
Manpreet Singh, Planetary Sciences, Postdoc (Federico)
Maggie Smith, Physics, Graduate (Paschalidis)
Amy Smock, Astronomy, Graduate (Daniel)
Peter Stephenson, Planetary Sciences, Postdoc (Koskinen)
Yang Sun, Astronomy, Graduate (Zabludoff)
Tomomi Sunayama, Astronomy, Postdoc (Eifler)
Connor Sweeney, Physics, Graduate (Rozo)
Wolfgang Kurt Vallazzq-Margl, Physics, Graduate (Su)
Jada Walters, Planetary Sciences, Graduate (Klein)
Erik Wessel, Physics, Graduate (Paschalidis)
Jiachuan Xu, Astronomy, Graduate (Eifler)
Ningyuan Xu, Astronomy, Graduate (Chan)
Jackson Zariski, Applied Math (Kratter )
Haowen Zhang, Astronomy, Graduate (Behroozi)
Xiaozhou Zhao, Planetary Sciences, Postdoc (Federico)


TAP Partners in AST, PHY, LPL

Faculty, postdocs, and students from a TAP department and who are participating in TAP Initiatives and/or collaborating with theorists:

Jeff Andrews-Hannah, Planetary Sciences
Daniel Apai, Astronomy
Xiaohui Fan, Astronomy
Alyson Ford, Astronomy
Brenda Frye, Astronomy
Richard Greenberg, Planetary Sciences
Pierre Haenecour, Planetary Sciences
Christopher Hamilton, Planetary Sciences
Lon Hood, Planetary Sciences
Ivan Hubeny, Astronomy
Buell Januzzi, Astronomy, Head
Jozsef Kota, Planetary Sciences
Mihailo Martinovic, Planetary Sciences
Sumit Mazumdar, Physics
Alfred McEwen, Planetary Sciences
Ilaria Pascucci, Planetary Sciences
Johann Rafelski, Physics
Kaushik Satapathy, Physics
Peter Strittmatter, Astronomy
Timothy Swindle, Planetary Sciences
Rodger Thompson, Astronomy
Tyler Trent, Physics
Kathryn Volk, Planetary Sciences

TAP Partners in Other Units

Faculty, postdocs, research scientists from other UA departments collaborating with TAP faculty:


Kobus Barnard, Computer Science
Bruce Bayly, Mathematics
Ali Berangi, Hydrology and Atmospheric Sciences
Misha Chertkov, Applied Mathematics
Laura Condon, Hydrology and Atmospheric Sciences
Solange Duhamel, Molecular and Cellular Biology
Chris Gniady, Computer Science
John Hartman, Computer Science
Kwan-Sung Jun, Computer Science
Tod Lauer, NOIRLab
Barney Maccabe, Institute for the Future of Data and Computing
Nirav Merchant, Data Science Institute
Edwin Skidmore, BIO5 Institute
Tyson Swetnam, BIO5 Institute
Xubin Zeng, Hydrology and Atmospheric Sciences
Helen Zhang, Mathematics


TAP Initiative Chairs

Chair persons are leading the TAP Initiatives and the TAP Visitor program and thereby interdisciplinary grant development efforts from the TAP Initiatives.   

Erik Asphaug, LPL, Planet Formation Initiative
Chi-kwan (CK) Chan, AST, Computation and Data Initiative
Ann Zabludoff, AST, Computation and Data Initiative
Gurtina Besla, AST, Cosmology Initiative
Tim Eifler, AST, Cosmology Initiative
Sam Gralla, PHY, Gravity
Vasilis Paschalidis, AST, Gravity
Kris Klein, LPL, Plasma Physics Initiative

TAP Committees

The TAP Steering Committee meets regularly to develop and operationalize TAP activities. Positioned to head up new TAP developments, Initiative Leads form the Steering Committee.

The TAP Colloquia Committee develops the biannual colloquia series, and invites and hosts speakers.

Colloquia Committee

Kris Klein, Planetary Sciences, Colloquia Committee
Kaitlin Kratter, Astronomy, Colloquia Committee
Elisabeth Krause, Astronomy, Physics, Colloquia Committee, Chair

Steering Committee

Gurtina Besla, Astronomy, Steering Committee, TAP Chair
Chi-kwan (CK) Chan, Astronomy, Steering Commitee
Joe Giacalone, Planetary Sciences, Steering Committee
Sam Gralla, Physics, Planetary Sciences, Steering Commitee
Kris Klein, Steering Committee
Eduardo Rozo, Physics, Steering Commitee
Andrew Youdin, Astronomy, Steering Commitee, TAP Deputy Chair



Steering Committee

The TAP is directed by a Steering Committee composed of six members and a chairperson with member representation equally distributed across the departments of physics, astronomy, and planetary sciences. The steering committee is responsible for making significant program decisions, including program funding priorities and allocations, selection of student prize recipients, new member applications, and general planning of annual program priorities and directions.  

Gurtina Besla, TAP Chair

Associate Professor, Steward Observatory

Dr. Gurtina Besla’s research focuses on the formation and evolution of low mass dwarf galaxies. Through numerical simulations, Dr. Besla explores the impact of gravitational interactions on the observed properties of low mass galaxies in various environments.

Dr. Besla is a world expert in the study of the closest example of an interacting pair of dwarf galaxies, the Large and Small Magellanic Clouds.

Gurtina’s research on these galaxies has overturned conventional wisdom, illustrating that the Magellanic Clouds are likely recent interlopers in our neighborhood rather than long term companions to our Galaxy.

Andrew Youdin, TAP Deputy Chair

Associate Professor, Steward Observatory

Dr. Andrew Youdin, received his Ph.D. from the University of California, Berkeley, in 2003. Dr. Youdin is a theoretical astrophysicist whose primary focus is the formation and evolution of planetary systems. Andrew employs various techniques, including analytic derivations, statistical data analysis, and detailed numerical simulations.

Current research topics include planetesimal formation, giant planet formation, exoplanet statistics and atmospheres, circumbinary dynamics, and accretion disks.  In ongoing work, Andrew investigates a range of planet formation mechanisms with an eye to ongoing breakthroughs in exoplanet, disk and Solar System observations.

Chi-Kwan Chan

 Associate Astronomer, Steward Observatory

Dr. Chi-kwan Chan (CK) is an Associate Astronomer/Research Professor at Steward Observatory, University of Arizona, and has been serving as the Secretary of the Event Horizon Telescope (EHT) Science Council since 2020. He recently led the publication of the computational and theoretical modeling/interpretation of our black hole, Sgr A*. Professor Chan created EHT’s computational and data processing infrastructure and continues to lead it to this day, along with EHT’s Software and Data Compatibility Working Group.

CK is a Senior Investigator of Black Hole PIRE, a leader of the Theoretical Astrophysics Program TAP, a Data Science Fellow, and a member of the Applied Mathematics Program. 

Kris Klein

Associate Professor, Lunar & Planetary Laboratory

Dr. Klein’s research focuses on studying fundamental plasma phenomena that governs the dynamics of systems within our heliosphere as well as more distant astrophysical bodies. He has particular interest in identifying heating and energization mechanisms in turbulent plasmas, such as the Sun’s extended atmosphere known as the solar wind, as well as evaluating the effects of the departure from local thermodynamic equilibrium on nearly collisionless plasmas which are ubiquitous in space environments.

Joe Giacalone

Professor, Lunar & Planetary Laboratory

Dr. Giacalone’s core research interests include understanding the origin, acceleration, and propagation of cosmic rays, and other charged-particle species in the magnetic fields of space, and general topics in space plasma physics, and astrophysics.

Joe develops physics-based theoretical and computational models which are used to interpret in situ spacecraft observations. He is interested in the general properties of solar, interplanetary, and galactic magnetic fields.

Currently, he is studying the origin of large solar-energetic particle events (a.k.a. solar cosmic rays) which involves a number of diverse aspects of solar physics and space physics. He has written papers describing the propagation of solar-flare particles from the Sun to the Earth where they are observed by spacecraft such as ACE, Ulysses, Wind, etc.

He is also interested in the general topic of particle acceleration in astrophysical plasmas.

Sam Gralla

 Associate Professor, Physics

Dr. Gralla works on a variety of problems in gravitational physics, plasma physics and astrophysics, with an emphasis on the regime where gravity and electromagnetism are strong. A unifying theme is that strong fields make for interesting physics and theoretical simplification that enables clean study of important processes.

Sam likes to work on problems that have both intrinsic interest and astrophysical application. Recent interests have included the two-body problem in general relativity, electromagnetic and gravitational self-force effects on the motion of bodies, strong-field (force-free) plasmas and quantum-electrodynamical corrections, and physics near rapidly rotating black holes.

Eduardo Rozo

Associate Professor, Physics

Dr. Rozo is an experimental cosmologist, utilizing large scale structure probes to better understand the physics behind the accelerated expansion of the Universe: that is, since gravity pulls, how is it possible for the expansion of the Universe to be accelerating? As of today, there are only two plausible solutions: either the energy budget of the Universe is dominated by a previously unknown form of mass—energy, or general relativity fails to be the correct description of gravity on cosmological scales. Resolving this dichotomy is the single most pressing question in observational cosmology today.

Eduardo’s research directly addresses this problem by utilizing the abundance galaxy clusters as a cosmological. His research exploits both photometric (e.g. Dark Energy Survey and Large Synoptic Survey Telescope), spectroscopic (Dark Energy Spectroscopic Instrument), and multi-wavelength data (Planck, South Pole Telescope, X-ray data from Chandra and XMM) to better understand this observational probe, and thereby safeguard against systematic uncertainties.

Colloquia Organizing Committee

Elisabeth Krause, Chair

Associate Professor, Astronomy & Physics

Dr. Krause joined the University of Arizona in August 2018. Elisabeth’s research focuses on the intersection of theoretical and observational cosmology. She is broadly interested in using observations of the large-scale galaxy distribution to constrain the composition and initial conditions of the Universe.

Elisabeth has worked on a wide range of topics and methods in Large Scale Structure research, from analytic calculations of systematic effects required for the interpretation of data from upcoming photometric and spectroscopic surveys, analysis of numerical simulations, to data processing and clustering measurements. She is leading the Theory and Joint Probes working group within the Large Synoptic Survey Telescopes’ Dark Energy Collaboration and co-coordinates the Theory and Combined Probes working group within the ongoing Dark Energy Survey.

Kristopher Klein

Associate Professor, Lunar & Planetary Laboratory

Dr. Klein’s research focuses on studying fundamental plasma phenomena that governs the dynamics of systems within our heliosphere as well as more distant astrophysical bodies. He has particular interest in identifying heating and energization mechanisms in turbulent plasmas, such as the Sun’s extended atmosphere known as the solar wind, as well as evaluating the effects of the departure from local thermodynamic equilibrium on nearly collisionless plasmas which are ubiquitous in space environments.

These systems are studied with a combination of analytic theory and numerical simulation, including large-scale nonlinear turbulence codes such as AstroGK and HVM. These theoretical predictions are compared to in situ observations from spacecraft including NASA’s Wind and MMS and the upcoming Parker Solar Probe mission. By comparing theory with local plasma measurements, we aim to answer a variety of questions about the behavior of plasma in our solar system.

Kaitlin Kratter

Associate Professor, Steward Observatory

Dr. Kratter is an associate professor in the Astronomy Department/ Steward Observatory at the University of Arizona. She works on a range of topics in theoretical astrophysics related to star formation, planet formation, disk dynamics, and n-body dynamics. I am also affiliated with the Theoretical Astrophysics Program and the Graduate Interdisciplinary Program in Applied Mathematics at the University of Arizona. 

Kaitlin’s research focuses on the formation and evolution of stellar and planetary systems. Kratter employs analytic and computational techniques to tackle topics including accretion disk dynamics, binary formation, few body dynamics, and planet-disk interactions. Her current work is focused on the intersection of binary and planet formation, especially in circumbinary systems. She is also collaborating closely with observers to discover extreme mass ratio binaries, and very young multiple star systems.