CITA News – Canadian Institute for Theoretical Astrophysics The Canadian Institute for Theoretical Astrophysics is a nationally supported research centre located at the University of Toronto that is devoted to studying the origin and evolution of the universe, and the many wonderful phenomena revealed by modern astronomy. Fri, 16 Oct 2026 19:13:15 +0000 en-US hourly 1 https://wordpress.org/?v=7.1.3 Welcoming the 2026 Cohort of CITA Fellows /welcoming-the-2026-cohort-of-cita-fellows/ /welcoming-the-2026-cohort-of-cita-fellows/#respond Fri, 16 Oct 2026 19:08:27 +0000 /?p=19292 Welcoming the 2026 Cohort of CITA Fellows

 

CITA extends a warm welcome to our incoming Fellows and National Fellows. This Fall we are joined by an unprecedented number of talented Postdoctoral and National Fellows. We are committed to providing post-doctoral training for early career researchers in the field of Theoretical Astrophysics and are excited about the contributions these outstanding researchers will bring to CITA.


Weikai Cui

Dr. Weikai Cui joined CITA as a Postdoctoral Fellow in October 2026 after earning his doctorate from the University of Virginia in 2026. His research focuses on astrochemistry, interstellar molecules, chemical processes in the interstellar medium, and reactions occurring on icy grain surfaces. His work combines theoretical and computational chemistry with astrophysical applications to understand the molecular evolution of interstellar environments and the chemical processes that precede star and planet formation.

Paul Huet

Dr. Paul Huet is joining CITA as a Postdoctoral Fellow in November 2026, after earning his doctoral degree at the Paris Observatory. His research focuses on planetary formation, planetary atmospheres, protoplanetary and debris disks, gas accretion onto planets, numerical modeling and observations, and exoplanets. His work combines numerical modeling with observations to investigate the formation and evolution of planetary systems, including the interaction between planets and their surrounding gaseous and dusty environments.

Sóley Hyman

Dr. Sóley Hyman is a CITA National Fellow at Queen’s University. She earned her Ph.D. from the University of Arizona in 2026. Her research focuses on galaxy dynamics, stellar orbits, chaos, and computational methods, with particular interest in the internal dynamics of galaxies. She studies how evolving stellar orbits drive morphological changes in galaxy simulations, including the role of chaotic stellar orbits in the evolution of bars and boxy-peanut-X (BPX) structures in disk galaxies.

Christian Kragh Jespersen

Dr. Christian Kragh Jespersen is a CITA National Fellow and Schmidt AI in Science Fellow. His research focuses on galaxy evolution, astrostatistics, machine learning, and spectroscopy. He develops statistical and machine-learning methods for studying how galaxies and dark-matter halos form and cluster, with research spanning JWST observations of early galaxies to the study of Earth’s own night-sky glow. His work combines astronomical observations with statistical and computational methods to extract physical information from large datasets.

Xuan Ji

Dr. Xuan Ji joined CITA as a Postdoctoral Fellow in October 2026, after receiving her Ph.D. in Geophysical Sciences from the University of Chicago in 2026. Her research focuses on rocky exoplanet atmospheres, climate, and habitability. She uses both low-order mathematical models and numerical simulations to study the coupled dynamics of small rocky exoplanets’ interiors, atmospheres, and orbits. At CITA, she will contribute to an international effort to develop next-generation computational frameworks that connect physics-based models of exoplanet interiors and atmospheres with limited observations.

Ilija Medan

Dr. Ilija Medan joined CITA as a Postdoctoral Fellow in July 2026. He earned his Ph.D. from Georgia State University in 2023 under the supervision of Dr. Sébastien Lépine and subsequently served as a VIDA Postdoctoral Fellow at Vanderbilt University from 2023 to 2026 under the supervision of Dr. Keivan Stassun. His research focuses on low-mass stars, the Solar Neighborhood and stellar populations, binary stars, spectroscopic surveys, astroinformatics and astrostatistics, and Milky Way chemodynamics. At CITA, he works under the advisement of Dr. Juna Kollmeier and contributes to SDSS-V, where he serves as FPS Design Implementation Lead, Solar Neighborhood Working Group Co-Chair, and a member of the Milky Way Mapper Data Analysis team.

William McClymont

Dr. William McClymont joined CITA as a Postdoctoral Fellow in September 2026 after completing his Ph.D. at the Kavli Institute for Cosmology, University of Cambridge. His research focuses on galaxy evolution, high-redshift galaxies, star clusters, supermassive black holes, radiation-hydrodynamic simulations, and Monte Carlo radiative transfer. He combines cosmological radiation-hydrodynamic simulations with observations to investigate why galaxies formed and grew so rapidly in the early Universe and how this relates to the formation of dense star clusters, including the progenitors of globular clusters.

Maja Lujan Niemeyer

Dr. Maja Lujan Niemeyer is an incoming CITA National Fellow at the University of British Columbia, where she will work with the CHIME group. She recently completed her Ph.D. in Physics at the Max Planck Institute for Astrophysics and Ludwig-Maximilians-Universität München, under the supervision of Professor Eiichiro Komatsu. Her research focuses on line-intensity mapping, large-scale structure, and the Lyman-α emission line, using observations of diffuse emission to study galaxies, intergalactic gas, and the evolution of the early Universe. She is a member of the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) collaboration. Her recent work includes the first detection of the galaxy–Lyman-α intensity cross-power spectrum in HETDEX data, providing a precise measurement of line-intensity mapping at cosmological scales.

Catherine Psarakis

Dr. Catherine Psarakis joined CITA as a Postdoctoral Fellow in October 2026 after completing her Ph.D. in the Department of Earth, Planetary, and Space Sciences at UCLA. Her research focuses on magnetic induction, icy moons, interior modeling, planetary habitability, astrobiology, alternative solvents, and planetary geochemistry. She combines planetary-interior and magnetic-induction modeling with laboratory experiments investigating ionic liquids and deep eutectic solvents under planetary conditions. Her work includes research conducted at NASA’s Jet Propulsion Laboratory and seeks to connect planetary geophysics, geochemistry, and astrobiology in understanding where persistent liquid environments may exist within Solar System bodies and exoplanets. She is also an AAUS Scientific Diver, with interests in terrestrial analogue environments for planetary science and astrobiology.

Soumendra Kishore Roy

Dr. Soumendra Kishore Roy is a Canada Impact+ Postdoctoral Fellow and a CITA Postdoctoral Fellow, who joined CITA in July 2026. He earned his Ph.D. from Stony Brook University in 2026. His research focuses on massive stellar evolution, gravitational-wave astrophysics, and gravitational-wave cosmology, with particular interest in population and cosmological-parameter inference. His core expertise is in hierarchical Bayesian inference, which he uses to connect models of binary stellar evolution with observations of compact-binary mergers and investigate their origins. He is involved in research associated with the LIGO–Virgo–KAGRA (LVK) Collaboration.

Sabina Sagynbayeva

Dr. Sabina Sagynbayeva is a CITA National Fellow whose research spans exoplanets, stars, astrostatistics, numerical simulations, theoretical astrophysics, and data analysis. Originally from Kazakhstan, she earned her Ph.D. from Stony Brook University. Her scientific interests include planet formation, the orbital architecture of exoplanets, and stellar magnetic activity. She also maintains an interdisciplinary creative practice in acting and singing.

Hui Tong

Dr. Hui Tong is joining CITA as a Postdoctoral Fellow after receiving his doctorate from Monash University in 2026. His research focuses on gravitational-wave astronomy, compact-object mergers, black-hole populations, and Bayesian inference. His work uses gravitational-wave observations to investigate the properties and origins of merging compact objects and the astrophysical populations that produce them. He is affiliated with the LIGO–Virgo–KAGRA (LVK) Collaboration and the OzGrav ARC Centre of Excellence for Gravitational-Wave Discovery.

Jonathan Zhang

Dr. Jonathan Zhang begins his Postdoctoral Fellowship at CITA after completing his doctorate at the University of Toronto in 2026. His research focuses on fast radio bursts and high-energy astrophysical phenomena, with particular interest in the physical mechanisms that generate these short-duration radio transients and their possible connections to magnetars and extreme magnetic environments.

Saiyang Zhang

Dr. Saiyang Zhang joins CITA as a Postdoctoral Fellow after completing his Ph.D. in Physics at the University of Texas at Austin in August 2026. His research focuses on dark matter, the early Universe, primordial black holes, Population III stars, supermassive black holes, and large-scale structure, combining theoretical modelling, cosmological simulations, and computational methods to investigate the evolution of cosmic structure. His recent work has examined how primordial black holes may influence the formation of the first stars and galaxies and potentially seed the supermassive black holes observed in the early Universe, including through observations with JWST. He is also increasingly interested in machine learning and scientific discovery, including simulation-based inference and the application of large language models to cosmology and dark-matter research.

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CITA Quarterly: New CITAzens and Other Updates /cita-quarterly-new-citazens-and-other-updates/ Sun, 18 Jan 2026 12:46:17 +0000 https://cita2026.wpenginepowered.com/?p=15060
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July – August – September

In this newsletter you will find a summary of recent faculty and council appointments, notable community engagements, and an overview of some of the excellent research being conducted at CITA. Additionally, our community has recently convened to recognize accomplishments, support emerging scientists, and establish new international partnerships.

We are especially happy to welcome our newest faculty member – Professor Pratika Dayal, who comes to CITA and the University of Toronto following her appointment at the University of Groningen. We also acknowledge the valued expertise joining of new members joining the CITA Council – Professor Evan McDonough, University of Winnipeg, and Professor Doug Johnstone, Principal Research Officer, Herzberg Astronomy and Astrophysics.

New Faculty and CITA Council Memebrs

CITA welcomes Professor Pratika Dayal from the Kapteyn Institute at Groningen University as a CITA faculty member. Prof. Dayal joined CITA on September 1st, 2025 as a tenured Professor cross-appointed with the Department of Astronomy & Astrophysics at the University of Toronto. She is an expert on galactic evolution, dark matter, galaxy formation, 21cm cosmology, multi-messenger astronomy, and astro-particle physics. Prof. Dayal is the Principal Investigator of the DELPHI project. Find out about the project and the team .

Professor Evan McDonough elected to CITA Council (2025-2029) Prof. McDonough is an Associate Professor at the University of Winnipeg and Director of the . He works at the intersection of high energy theoretical physics, astrophysics, cosmology, and particle physics. In his role on CITA Council, Prof. McDonough will make scientific assessments and provide recommendations for funding decisions furthering Canadian theoretical astrophysics.

Professor Doug Johnstone elected to CITA Council (2025-2027) Doug Johnstone is a Canadian astronomer and Principal Research Officer at the Herzberg Astronomy and Astrophysics Institute of the National Research Council of Canada. He is an authority on far-infrared and sub-millimeter astronomy focusing on star and planet formation. He is PI of JWST Planets in Formation Guaranteed Time Program and CPI of JCMT Transient Survey Large Program.

Research and Publication Highlights

  • (September 16) New EHT Images Reveal Black Hole’s Magnetic Field Flips Direction. Dr. Sebastiano D. von Fellenberg, a postdoctoral researcher at the Canadian Institute for Theoretical Astrophysics, Max Planck Institute for Astronomy (MPIfR) and Humboldt Feodor Lynen Fellow is a key contributor to this latest  publication. Leading the calibration of the new 2021 observations, he corrected for atmospheric interferences and slight differences between the telescopes. Other members of the EHT collaboration at the University of Toronto include CITA faculty members Ue-Li Pen and Bart Ripperda, postdoctoral fellows Gibwa Musoke and Rohan Dahale and Aviad Levis, Assistant Professor at the Computer Science Department. Read more on CITA’s website.
  • (August 27 – October 28) 10 Years after the first event detection LVK releases a large catalog of event candidates. Over the summer and fall, the global network of gravitational-wave observatories operated by the LIGO – Virgo-KAGRA (LVK) Collaboration released a huge new logbook of cosmic collisions – its fourth Gravitational-Wave Transient Catalog (GWTC-4.0). This latest update adds 128 new gravitational-wave candidates, more than doubling the count of logged events to date. The CITA Flagship and CITA Inc Gravitational-Wave researchers (Reed Essick, Maya Fishbach, Aditya Vijaykumar, Aryanna Schiebelbein-Zwack, Utkarsh Mali, Amanda Farah, Samar-Safi Harb, Labani Mallick) have a central role in this important international collaboration. Find more details and a list of published papers below: CITA Researchers Spearhead Astrophysical Interpretation of Record-Breaking Gravitational Wave Run;ÌýNew events from LIGO’s 4th Observing Run Match Formation Channel Predicted by CITA Fellow Claire Shi Ye
  • (July 4) Ioana Zelko, CITA Postdoctoral Fellow and Bart Ripperda, faculty member, have been awarded 32K A100 GPU-Hours on  for their project, ”GPU Framework for Real-Time Calculation of 3D Interstellar Radiation Fields”.  is donating the GPU hours to CITA as part of its Academic Grant Program. Check out  visualization created by Ioana Zelko.

Seven people stand behind a table with a CITA logo on it
Left to right in the back: Prof. Dick Bond, Prof. Ue-Li Pen, Prof. Pratika Dayal, Prof. Norman Murray, Prof. Reed Essick. At the front: CITA Director Shantanu Basu and Professor Jun’ichi Yokoyama, Director of IPMU.

Events, Workshops, Collaborations

  • () Signing Ceremony for a new MoU between CITA and IPMU, University of Tokyo
    Expanding the frontiers of collaboration with a new memorandum of agreement between the Canadian Institute for Theoretical Astrophysics and the Kavli Institute for the Physics and Mathematics of the Universe (IPMU) at The University of Tokyo. Professor Jun’ichi Yokoyama, Director of IPMU, visited from Japan for a special signing ceremony that took place at CITA. As CITA Director, Shantanu Basu, pointed out, the signing of this MoU will enhance personal ties and initiate plans for many collaborations and mutual visits between the two institutes: “Our two institutions are committed to a free flow of ideas and visitors as we jointly explore the most fundamental questions about the Universe.
  • () 2025 Summer Undergraduate Research Fellows Receive their Certificates
    Congratulations to CITA SURFers 2025, who completed their summer research projects with stellar presentations on August 22 and celebrated their achievements with cake! Thank you to all the supervisors and mentors (Reed Essick, Maya Fishbach, Aditya Vijaykumar, Ioana Zelko, PhD, Biprateep Dey, Claire Shi Ye, Neige Frankel, Aryanna Schiebelbein-Zwack) for your hard work and guidance! Another summer to remember at the Canadian Institute for Theoretical Astrophysics.
  • () Celebrating CITA Scholarship and Achievements. The CITA community came together to celebrate a remarkable season of success. We honoured our brilliant faculty and research fellows for their outstanding achievements and recent prestigious awards. CITAzens were especially honoured to be joined by the University of Toronto President Melanie Woodin, who shared in the celebration and personally congratulated Prof. Dick Bond (Shaw Prize in Astrophysics) and Prof. Norman Murray (FCAP, FAAAS, U.S. National Academy of Sciences Member, FAAS) on their exceptional distinctions. Other special guests were Natural Sciences and Engineering Research Council of Canada (NSERC) Director of Discovery Research and Recognition Sarah Overington and Vice-Provost, Strategic Enrolment Management Dwayne Benjamin. It was an inspiring afternoon recognizing the groundbreaking work happening at CITA and the incredible talent that drives it. On October 21st, Prof. Bond accepted the Shaw Prize in Astrophysics at a special ceremony in Hong Kong. Listen to his .
  • () A group of CITAzens visited the vault of the University of Toronto Art Museum. They saw rarely displayed Canadian Heritage artworks. Special thanks to CITA graduate student  for organizing this visit and Alex King (Collections Coordinator at the ) for showing us around!

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From left to right: Prof. Peter Martin, Prof. Dick Bond, Director Shantanu Basu, President Melanie Woodin, Prof. Norman Murray.
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Renowned planetary scientist Sara Seager joins U of T and the Canadian Institute for Theoretical Astrophysics as North Star Distinguished Professor /renowned-planetary-scientist-sara-seager-joins-u-of-t-and-the-canadian-institute-for-theoretical-astrophysics-as-north-star-distinguished-professor/ Wed, 12 Nov 2025 12:40:01 +0000 https://cita2026.wpenginepowered.com/?p=15058

A pioneer in the study of exoplanets and exoplanet atmospheres,Ìý is returning to her alma mater, the University of Toronto (U of T), to join the Canadian Institute for Theoretical Astrophysics (CITA) as North Star Distinguished Professor, starting September 1, 2026.

“I’m excited to return home as a faculty member, researcher and mentor at the institution where my academic journey began, and to push the boundaries of discovery with forward-thinking collaborators across disciplines,” says Seager, a native Torontonian and U of T alum who grew up a few blocks from the downtown campus.

Seager’s research will be supported through cross-appointments with the Departments of Ìý²¹²ԻåÌý,Ìýas well as the  with funding from the Dunlap Institute for Astronomy & Astrophysics.

She joins CITA from the Massachusetts Institute of Technology (MIT) where she will complete her tenure as Professor of Physics, Professor of Planetary Science and Professor of Aeronautics and Astronautics. Prior to MIT, she was with the Carnegie Institute of Science and the Institute for Advanced Study, Princeton, New Jersey. In 1999, she received her PhD from Harvard University. In 2023, she received an  for her leadership in the fields of astrophysics and planetary science. She earned a bachelor of science in the math and physics specialist program at U of T in 1994.

Throughout her distinguished career, which includes the Kavli Prize in Astrophysics, a MacArthur Fellowship (or “genius grant”) and the distinction of Officer of the Order of Canada, Seager has conducted ground-breaking research into the detection and study of exoplanet atmospheres, with a focus on what those observations reveal about the possibility and presence of life.

Seager’s quest for Earth-like exoplanets — “Earth 2.0”— and signs of life on them guides her efforts in space-based searches. She was Deputy Science Director of the NASA space mission , a space telescope which has discovered hundreds of planets orbiting nearby stars. She led NASA-sponsored Starshade mission concept studies, establishing the feasibility of starshade science and technology for directly imaging Earth-sized exoplanets around nearby Sun-like stars. Her search also includes missions designed to look for signs of life closer to home, within the atmosphere of Venus.

“We are delighted to welcome Professor Seager to the CITA community,” says ,Ìýinterim director of the institute. “Her visionary leadership in exoplanet research, especially her groundbreaking work on atmospheric characterization and the search for biosignatures, aligns perfectly with CITA’s mission to push the frontiers of theoretical astrophysics.”

CITA is Canada’s national research centre based in the Faculty of Arts & Science at U of T and is dedicated to the advancement of theoretical astrophysics and our understanding of the universe. Its dual mission is to foster interactions within the Canadian astrophysics community, in part through its national postdoctoral fellowships, postdoctoral and research associate fellowships, and extensive student supervision.

“Professor Seager’s arrival marks an incredibly exciting moment for the faculty, CITA and the Canadian scientific community,” says Stephen Wright, interim dean of the Faculty of Arts & Science. “Her inventive, interdisciplinary research agenda promises to ignite new collaborations and inspire a new generation of scientists.”

As for what she has planned for when she arrives, Seager will establish an ambitious interdisciplinary research program. This initiative will rethink the habitability of planets and accelerate the search for life across the cosmos. Her program is built upon the synergy of exoplanet astronomy, laboratory organic chemistry, computational physics and aerospace engineering.

She will also continue to lead the , a series of privately and publicly funded space missions to Venus. The first mission, in partnership with Rocket Lab, will launch a spacecraft to Earth’s solar system neighbour, targeted for 2026. The series of missions will study Venus’s atmosphere to search for organic molecules that could indicate the presence of life.

“U of T has consistently led the way in transformative research,” said Seager. “I’m deeply honoured to join this community of visionary thinkers dedicated to innovation and impact.”

Find more details on ,ÌýÌý²¹²ԻåÌý. Listen to an interview with Professor Seager on ,Ìý.

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