CITA - ICAT

How do exploding stars shape the structure of our galaxy?

For decades, the standard assumption in astrophysics has been that galactic turbulence operates top-down. Energy released by massive galactic explosions progressively breaks down into smaller and smaller vortices.

However, new research authored by CITA - ICAT Postdoctoral Fellow Dr. James Beattie, demonstrates that supernova remnants can actually drive an "inverse cascade." By creating microscopic, chaotic swirls at the boundaries of expanding gas shells, these explosions seed turbulence that merges and builds upward.

Powered by the advanced computational capabilities of the at the University of Toronto, these simulations suggest that current models of galaxy evolution and star formation may need to be carefully re-evaluated. As Dr. Beattie notes, "understanding microscopic physical instabilities is essential to understanding the large-scale universe".

Read more in the News section of CITA's website: https://www.cita.utoronto.ca/supercomputer-reveals-exploding-stars-stir-galaxy-bottom/

What a fantastic kickoff to CITA@40!
This morning, the Director of CITA - ICAT, Shantanu Basu, and the University of Toronto President, Melanie Woodin, officially opened our milestone conference, welcoming a distinguished group of astrophysicists from across the globe to the University of Toronto.
Welcoming remarks were also given by the Dean of the University of Toronto Faculty of Arts & Science, Prof. Stephen Wright and the Nobel Laureate in Physics, Arthur B. McDonald.

For half a century, CITA - ICAT Professor Dick Bond has been at the forefront of answering humanity’s biggest questions.

This fantastic piece by Mariam Matti from UofT News highlights his incredible 50-year career as a University Professor at University of Toronto. From the early days of Big Bang cosmology to the establishment of CITA as a global powerhouse, Professor Bond's work has been essential to decoding the universe.

Dive into the story about his research on the cosmic web, and the evolution of astrophysics over the last half-century:

CITA - ICAT & University of Toronto Faculty of Arts & Science researcher Dick Bond has spent 50 years trying to understand the universe. He’s making progress 🌌 uoft.me/bond-d

Connecting with the next generation of scientists is always exciting! It was a pleasure hosting "Voyager" yesterday. This group of 32 undergraduate students, all majoring in astronomy at the University of Groningen in the Netherlands, were eager to learn about current research projects at CITA - ICAT.
On the side of the hosts, CITA Graduate student Alicia Savelli kicked things off by unraveling the mysteries of Black Holes. Postdoctoral Fellow Vera Delfavero guided the students through the bleeding edge of Gravitational Wave Research, Sebastiano von Fellenberg (Postdoctoral Fellow) took everyone on a journey using the NASA's James Webb Space Telescope ( ) to explore the Supermassive Black Hole at the center of our galaxy. And, Biprateep Dey (Postdoctoral Fellow) wrapped up the science sessions with a fascinating look at how Artificial Intelligence is transforming astrophysics research.

A huge thank you to the Voyager students for making the trip across the Atlantic to visit us. We wish you the absolute best in your continued studies! 🚀

What is on the bleeding edge of gravitational-wave astronomy? 🌌🌊
From April 20 to 22, CITA is thrilled to host "GWTC-6: The Bleeding Edge of Gravitational-Wave Populations." This interactive workshop will bring together LIGO-Virgo-KAGRA members to dive deep into forthcoming catalogs of gravitational-wave (GW) data.
📢 Local UofT & CITA Researchers: You’re Invited!
While the main workshop is for LVK members, we are opening the doors for our first morning session on Monday, April 20 (9 AM – 1 PM) to all researchers at CITA and the University of Toronto.
Join us for coffee and a fantastic morning of talks exploring the current state of the field, astrostatistics, and how GW research connects with other branches of astrophysics.
Hear from our very own:
🗣️ Reed Essick – What to Expect from GWTC-5 and 6
🗣️ Claire Ye – A Theorist’s Wish List from GWs
🗣️ Maya Fishbach – Synergies Between GWs and Other Astrophysical Probes
🗣️ Josh Speagle – Why Do Astrostatistics?
🗓️ Date: Monday, April 20
📍 Location: Seminar Room (MP1318A)

Organizers: Aditya Vijaykumar and Amanda Farah

How does a chaotic cloud of cosmic gas turn into a stable, planet-forming solar system? 🪐✨
An international team of researchers—including CITA’s Interim Director, Shantanu Basu—has just published groundbreaking findings in the Astrophysical Journal that solve a decades-old mystery in star formation.
We’ve long known that planets form in flat, spinning disks of gas and dust around young stars. But exactly how the material falling from the massive outer cloud "hits the brakes" and organizes into a stable, spinning disk has been a major puzzle.
Led by Indrani Das at the Academia Sinica Institute of Astronomy and Astrophysics, the team discovered the missing link: EnDTranZ (the Envelope Disk Transition Zone).

Read more on CITA's website: https://www.cita.utoronto.ca/

Why are black holes heavier than 45 solar masses so rare? Because the giant stars that would normally create them don't just die—they completely obliterate themselves in massive 'pair-instability' supernovae, leaving no core behind to form a black hole.
In a paper just published in Nature, CITA - ICAT Professor Maya Fishbach and Postdoctoral fellows Aditya Vijaykumar and Amanda Farah, confirm that black holes with masses larger than 45 times the mass of the sun are the result of previous black hole mergers, rather than the collapse of enormous dying stars.

Read more: https://www.cita.utoronto.ca/new-study-finds-evidence-cosmic-explosions-missing-black-holes/

Picture: Artist's rendition of a pair-instability supernova, a rare and powerful stellar explosion, which can be probed by black hole mergers. Credit: Carl Knox

Dr. James Beattie, Postdoctoral Fellow at - ICAT and Princeton University was awarded a prestigious Hubble Fellowship, announced the Telescope Science Institute on behalf of NASA today.

The fellowship will allow him to build the next generation of supercomputer models to probe how the early Universe may have become magnetized by the first stellar explosions, and how some of the strongest magnetic fields in merging compact objects are created. Dr. Beattie will carry out this groundbreaking research at the Institute for Advanced Study in Princeton, beginning in the fall of 2026.

Please join us in congratulating Dr. Beattie on this outstanding achievement and wishing him the best as he takes his next steps at the Institute for Advanced Study!

Read more: https://www.cita.utoronto.ca/cita-postdoctoral-fellow-james-beattie-wins-hubble-fellowship-decipher-origin-magnetic-fields-early-universe/

How did the grassroots initiative of four friends lead to the building of a world-renowned institute for theoretical astrophysics? In this retrospective video, CITA's founders and early directors (Richard Henriksen, Peter Martin, Dick Bond, and Scott Tremaine) share the story of the Institute's creation.

Register for the CITA@40 Meeting and join us in celebrating the curiosity, courage, and spirit of discovery that established CITA and continue to shape the future of theoretical astrophysics!
Place: University of Toronto
Dates: May 27-29, 2026
https://conference.cita.utoronto.ca/event/2/page/2-registration

https://www.youtube.com/watch?v=NagXi4EY3XE

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