Astronomy &amp; Astrophysics

Indigenous Initiatives

Indigenous

Truth and Reconciliation

Subheadline

The groundwork is currently being laid for a coding club and mentoring programs, among other initiatives

A group of astronomers from the ��Ƶ and students, teachers and caregivers from Toronto’s Kâpapâmahchakwêw – Wandering Spirit School recently shared a once-in-a-lifetime experience: witnessing a total solar eclipse.

The April 8 gathering, which took place in Chiefswood Park on Six Nations of the Grand River, saw the astronomers bring telescopes with solar filters that allowed viewers to observe sunspots and watch as the moon slowly eclipsed the sun. The event also served as a forum for young learners and community members to share traditional knowledge and ask plenty of questions.

It was one of many engagements planned as part of a partnership between U of T’s Dunlap Institute for Astronomy & Astrophysics and the Kâpapâmahchakwêw – Wandering Spirit School, which was founded in 1977 and gives students from kindergarten to Grade 12 the opportunity to learn about Anishinaabe cultural traditions.

Totality at Chiefswood Park (photo by Kara Manovich)

In the future, there are also plans for a coding club, mentoring and tutoring programs, and training for teachers.

“Kâpapâmahchakwêw – Wandering Spirit School is grateful for the growing partnership with Dunlap because it provides an opportunity to practise reciprocity in knowledge sharing,” said Elise Twyford, the school’s principal. “The students and community learned about – and experienced – astrophysics and astronomy, and also had the opportunity to build their skills in sharing traditional knowledge and world views.

“I appreciate the care and thoughtfulness of the Dunlap and ��Ƶ team in collaborating with Kâpapâmahchakwêw students as partners in learning.”

The roots of the partnership stretch back to 2022 when Emma Stromberg, Indigenous partnership adviser at the Faculty of Arts & Science, and Associate Professor Susan Hill, director of the Centre for Indigenous Studies, approached Dunlap with an opportunity to work with teachers and students from Kâpapâmahchakwêw.

A close-up photo of the moon totally eclipsing the sun on April 8 above Chiefswood Park (photo by Suresh Sivanandam)

“We wanted to see if we could match up the needs and interests of the school to resources at U of T, to build something that can be sustained,” Stromberg says. “Consistent with U of T’s commitments to reconciliation, it is incumbent on all of us to think of ways to redress, in small and big ways, the impacts of settler colonialism and push resources into the community wherever possible.”

Some 20 members of the Dunlap community have since volunteered to help, with many of them recently participating in a workshop with John Croutch from the Office of Indigenous Initiatives to learn about the continued impacts of settler colonialism and what it means to be an ally to Indigenous Peoples.

The U of T astronomers said the opportunity to share a total solar eclipse was a memorable moment for everyone involved.

“You could hear lots of kids screaming in excitement and people gasping in awe at seeing totality,” said Associate Professor Suresh Sivanandam, interim director of the Dunlap Institute for Astronomy & Astrophysics in the Faculty of Arts & Science. “When I walked out of there, I thought, ‘These are the moments in my job where I feel completely fulfilled because I helped other people experience the joy of astronomy.’”

Students recreate the total solar eclipse with paint and pastels on black paper (photo by Emma Stromberg)

Professor Roberto Abraham, chair of the faculty’s David A. Dunlap department of astronomy and astrophysics, said he was the same age as some of the students when he first saw a total solar eclipse.

“It was magic,” he said. “Once you see a total solar eclipse, you won’t be the same person afterwards.”

Earlier this year, Sivanandam and Abraham visited the school to meet students, teachers and staff and hear about how astronomers at U of T can best support them.

For Twyford, the relationship with U of T immerses Kâpapâmahchakwêw students in the fields of astronomy and astrophysics in ways that wouldn’t be possible in the classroom.

“I know that many students now see the wonder and possibility of these sciences and are even more motivated to continue their learning,” Twyford said. “It also helps to complement the traditional and cultural.”

'A black box in astronomy knowledge': PhD researcher probes the earliest stars in the universe

Christopher.Sorensen — Tue, 26 Mar 2024 18:20:25 +0000

'A black box in astronomy knowledge': PhD researcher probes the earliest stars in the universe

Christopher.Sorensen Tue, 03/26/2024 - 14:20

Cutline

PhD researcher Margaret Ikape presents at the Astronomy on Tap T.O. event (photo by Alicia Richardson)

Michael Pereira

Topic

Graduate Students

Subheadline

Margaret Ikape is working to determine the properties of the first stars and how they influenced everything that followed

As a child, Margaret Ikape had a prime view of the stars from her hometown of Lagos, Nigeria.

“When I was really young, I saw a shooting star. And that got me looking up at the night sky a lot more,” Ikape says. She recalls thinking: “Can I count all the stars? Can I really go to a star? What would it be like if I could really go to a star? How long would it take?”

Today, Ikape is still looking at stars with the same curiosity, albeit ones that are much farther away. A PhD researcher at the ��Ƶ’s Dunlap Institute for Astronomy & Astrophysics and David A. Dunlap Department of Astronomy & Astrophysics, she’s working to tell the story of the first stars in the universe, and how they influenced everything that followed.

Theory predicts that ultraviolet light from the first stars was so powerful that it ionized — or split — some of the first hydrogen atoms back into protons and electrons. This period of cosmic history is known as the Epoch of Reionization (EoR). During this time, the first stars and galaxies began to form, and with them, the universe as we know it today.

Ikape is working to determine the properties of these first stars, like how big they were and how long the reionization took. “That period is like a black box in astronomy knowledge. We know it happened, because the universe is ionized today, but we don’t know many details about it,” Ikape says.

A representation of the evolution of the universe over 13.77 billion years (image by NASA / WMAP Science Team)

Current optical telescopes cannot see back far enough to capture the EoR, so Ikape uses thousands of computer simulations to reimagine it and test theories in a kind of virtual sandbox shaped by what we know of the universe. Some of these simulations require significant processing power and must be run through the “Helen” computing cluster, named after renowned Canadian astronomer Helen Sawyer Hogg.

Ikape also learns about the EoR by studying the first light emitted in the universe, the Cosmic Microwave Background (CMB). As light from the CMB travels to Earth, it passes through all that is between us and the point in cosmic history at which the CMB was emitted, approximately 380,000 years after the Big Bang. Ikape can isolate how light from the CMB was impacted by the EoR and analyze it to tell us more about this time.

“Margaret’s work connects models and simulations of how the first stars in the universe lit up and ionized the surrounding gas with our observations of the cosmic microwave light—so she is the detective piecing the story together,” says Associate Professor Renée Hložek, Ikape’s PhD supervisor.

Ikape has forecasted that a new generation of telescopes will unlock more details about this mysterious period and the universe’s first stars, including the Simons Observatory and the fourth-generation ground-based cosmic microwave background experiment, or CMB-S4. She co-authored research that predicts that the CMB-S4 will help scientists close in on when the EoR began and how long it lasted.

A nine-year Wilkinson Microwave Anisotropy Probe (WMAP) heat map of temperature fluctuations in the CMB (photo by NASA/WMAP)

When she isn’t unpacking the mysteries of distant stars, Ikape is involved in outreach initiatives on the ground.

She’s an instructor with the Pan-African School for Emerging Astronomers, a bi-annual school for emerging astronomers in Africa that aims to introduce astronomy undergraduate students to research practices and career avenues in the field, and participated in its inaugural program in Zambia in 2022.

In Toronto, Ikape was recently a speaker at Astronomy on Tap and has given presentations on astronomy at libraries, high schools and even a long-term care home.

“We are lucky to have students like Margaret at the Dunlap Institute; she combines her scientific curiosity with a passion for sharing what she learns with the broader community and training the next generation of bright minds,” Hložek says.

“The universe fascinates me a lot and I’m super excited every time I think about it," Ikape says. "So I think that everybody should know about it.”

U of T researcher seeks out new insights on the universe's oldest galaxies

Christopher.Sorensen — Thu, 08 Feb 2024 19:27:46 +0000

U of T researcher seeks out new insights on the universe's oldest galaxies

Christopher.Sorensen Thu, 02/08/2024 - 14:27

Cutline

Jacqueline Antwi-Danso, a postdoctoral researcher with the David A. Dunlap department of astronomy and astrophysics, is studying massive galaxies that formed “when the universe was still just a baby” (supplied image)

Chris Sasaki

Topic

Black

Indigenous

Statistical Sciences

Subheadline

"We're trying to understand why these galaxies formed the way they did and how they became so big so quickly"

Jacqueline Antwi-Danso remembers a book from her junior high school library describing how stars are born and how the most massive stars die in gigantic explosions called supernovae.

“The book explained that there were objects out in space that gave off so much energy we could see and study them and make precise observations of their physical properties,” says Antwi-Danso, who credits her parents for nurturing her interest in education and reading while growing up in Ghana. “That just blew my mind.”

Today, Antwi-Danso is an NSERC Banting postdoctoral fellow at the ��Ƶ’s David A. Dunlap department of astronomy and astrophysics in the Faculty of Arts & Science. Her work focuses on studying massive galaxies that formed “when the universe was still just a baby.”

She is also active in supporting Black, Latinx and Indigenous women who are interested in a career in science.

She recently spoke to U of T’s Chris Sasaki about her career, research and goals.

Was there an important milestone in your journey to becoming an astronomer?

After high school, my plan was to take a gap year to figure out if I wanted to stay in Ghana and do something in the sciences at the university level or go elsewhere.

That’s when an opportunity came my way. There was a program run by the American Embassy in Accra for Ghanaian high school students interested in studying in the U.S. It provided mentorship for things like how to apply to schools in the U.S., how to write a good college application and how to select courses. They also helped you think about what you wanted to do in your career.

It was a big turning point in my life when I was selected to join the program. That’s how I learned about opportunities outside of Ghana and realized that if I was going to study astronomy, I would have to leave because we don't have astronomy at the collegiate level. And so, I made my decision to study astronomy at Texas Christian University.

Large, relatively nearby galaxies like this one took billions of years to form. Antwi-Danso is trying to determine how large galaxies in the very distant universe formed in a small fraction of that time (photo by ESA/Hubble & NASA, D. Jones Acknowledgement: G. Anand, L. Shatz.)

As an astronomer, what questions are you trying to answer?

I study massive galaxies in the very distant universe – some of the very first structures that formed after the Big Bang nearly 14 billion years ago. We're trying to understand why these galaxies formed the way they did and how they became so big so quickly. We’re finding them at increasingly earlier times, as far back as when the universe was just four per cent of its current age.

This goes against our understanding of the hierarchical formation of large structures – where massive galaxies like our Milky Way galaxy were formed from the merger of galaxies that were formed from stars, which, in turn, formed from clouds of gas and dust.

For our galaxy, it took billions of years to attain its current stellar mass. These distant, massive galaxies had only a fraction of the time to go through this process, so we have no idea how they formed so quickly. So, one of two things is happening: either there's something wrong with our observations or we need to revise our current models. That's the big problem I'm working on and I’m actually looking for a summer undergraduate student to work on this project.

Jacqueline Antwi-Danso speaks to students at a meeting of the American Astronomical Society (supplied image)

You’re working to support Black, Indigenous and Latinx women in science. Can you tell me more about that?

The League of Underrepresented Minoritized Astronomers (LUMA) is a peer mentoring organization for women in astronomy, physics and the planetary sciences that was formed in 2015 by Catherine Espaillat, who is the director of the Institute for Astrophysical Sciences at Boston University. She started LUMA because, as a Dominican American grad student, she felt isolated.

There weren’t many people in her field who looked like her, with whom she shared backgrounds. So, she created LUMA to be a community of people with similar experiences who could provide each other with support. I joined because I also realized there weren't many people in my field who looked like me. There were even fewer African astronomers. And, like Catherine, I wanted a place where we could come together as a community and support each other.

Do have you have plans to do the same type of work here in Canada?

I would like to continue this work, so I've been learning about and trying to understand what the Canadian science landscape looks like. I think the challenge in Canada is similar to the challenge that LUMA faces in the U.S. – there are very few Black, Indigenous or Latinx women in science in either country. So, yes, I would like to do similar work here. I just don't know what that looks like yet.

What about in Ghana?

One thing that I had in mind was trying to create some sort of pipeline for students in Ghana who might be interested in astronomy and might want to study in the U.S. or Canada. There are challenges, of course, but I’m talking to people who have been involved in similar projects and have found solutions to these challenges. For example, it might mean helping by providing mentorship to students who are already interested in physics and to students who are a little further along in their studies. I'm hopeful there are a number of ways to make this work.

How do you feel about receiving the NSERC Banting fellowship?

I’m very grateful and humbled to receive it. For me, it represents an exciting opportunity to work independently on my research, especially at U of T with all the people in the Dunlap Institute (for Astronomy & Astrophysics), the department of astronomy and astrophysics, CITA (Canadian Institute for Theoretical Astrophysics) and the department of statistical sciences. I feel like U of T is the perfect place for me because I’m combining astronomy with statistics and cosmological simulations to understand these really massive, distant galaxies. I’m having the time of my life, and I’m looking forward to seeing what the next few months will bring.

U of T astronomers discover first population of binary stripped stars

rahul.kalvapalle — Wed, 20 Dec 2023 15:22:31 +0000

U of T astronomers discover first population of binary stripped stars

rahul.kalvapalle Wed, 12/20/2023 - 10:22

Cutline

Artist's impression of a massive star stripping the hydrogen envelope of its companion star in a binary system (illustration by Navid Marvi, courtesy of the Carnegie Institution for Science)

Michael Pereira

Topic

Research and Innovation

Subheadline

New findings confirm the existence of hot helium stars long thought to be at the heart of hydrogen-poor supernovae and neutron star mergers

Astronomers at the ��Ƶ have discovered a population of massive stars that have been stripped of their outer hydrogen layer by companion stars.

For over a decade, scientists have theorized that approximately one in three massive stars are stripped of their hydrogen envelope in binary systems (systems where two stars are gravitationally bound to one another). Yet, until now, only one possible candidate had been identified.

The findings, published in Science, shed light on the hot helium stars that are believed to be the origins of hydrogen-poor core-collapse supernovae and neutron star mergers.

“If it turned out that these stars are rare, then our whole theoretical framework for all these different phenomena is wrong, with implications for supernovae, gravitational waves and the light from distant galaxies,” said Maria Drout, assistant professor in the David A. Dunlap department of Astronomy & Astrophysics at the ��Ƶ and an associate at the Dunlap Institute for Astronomy & Astrophysics.

“This finding shows these stars really do exist.”

It also opens up possibilities for more detailed research going forward. “For example, predictions for how many neutron star mergers we should see are dependent on the properties of these stars, such as how much material comes off of them in stellar winds," Drout says. "Now, for the first time, we’ll be able to measure that, whereas people have been extrapolating it before."

Assistant Professor Maria Drout with the Magellan Telescope at Las Campanas Observatory (photo by Tom Holoien/Maria Drout)

Drout and her colleagues propose that these newly discovered stars will eventually explode as hydrogen-poor supernovae. These star systems are also thought to be necessary to form neutron star mergers.

In fact, the researchers believe that a few objects in their current sample are stripped stars with neutron star or blackhole companions. These objects are at the stage immediately before they become double-neutron-star or neutron-star-plus-blackhole systems that could eventually merge.

“Many stars are part of a cosmic dance with a partner, orbiting each other in a binary system. They’re not solitary giants but part of dynamic duos, interacting and influencing each other throughout their lifetimes,” says Bethany Ludwig, a PhD student in the David A. Dunlap department of Astronomy & Astrophysics and third author on the paper. “Our work sheds light on these fascinating relationships, revealing a universe that is far more interconnected and active than we previously imagined.

“Just as humans are social beings, stars too, especially the massive ones, are rarely alone.”

(Left to right): Bethany Ludwig, Anna O’Grady, Maria Drout and Ylva Götberg (all authors on the paper) at the Magellan Telescopes at Las Campanas Observatory in Chile (photo by Ylva Götberg)

As stars evolve and expand to become red giants, the hydrogen at the outer edges of one can be stripped by the gravitational pull of its companion star – leaving a very hot helium core exposed. The process can take tens of thousands or even hundreds of thousands of years.

Stripped stars are difficult to find because much of the light they emit is outside of the visible light spectrum and can be obstructed by dust in the universe or outshone by their companion stars.

Drout and her collaborators began their search in 2016. Having studied hydrogen-poor supernovae during her PhD, Drout set out to find the stripped stars thought to be at the heart of these supernovae during a NASA Hubble postdoctoral fellowship at the Observatories of the Carnegie Institution for Science.

The researchers, who include co-author Ylva Götberg, assistant professor at the Institute of Science and Technology Austria, later designed a survey to look in the ultraviolet part of the spectrum where extremely hot stars emit most of their light. Using data from the Swift Ultra-Violet/Optical Telescope, they collected brightness data for millions of stars in the Large and Small Magellanic Clouds, two of the closest galaxies to Earth.

Ludwig, who developed the first wide-field UV catalogue of the Magellanic Clouds, used UV photometry to detect systems with unusual UV emissions – signaling the possible presence of a stripped star.

The researchers used this ultraviolet dataset of the Large and Small Magellanic Clouds, the two closest major galaxies to our own, to identify the candidate systems (image by NASA/Swift/S. Immler (Goddard) and M. Siegel (Penn State)

The team carried out a pilot study of 25 objects, obtaining optical spectroscopy with the Magellan Telescopes at Las Campanas Observatory between 2018 and 2022, and demonstrated that the stars were hot, small, hydrogen-poor, and in binary systems – all consistent with their model predictions.

Currently, the researchers are continuing to study the stars identified in the paper and expanding their search to find more. They will be looking both within our own Milky Way and nearby galaxies with approved programs on the Hubble Space Telescope, the Chandra X-ray Telescope, the Magellan Telescopes and the Anglo-Australian Telescope.

As part of this publication, all theoretical models and data used to identify these stars have been made public and available to other scientists.

Collaborating institutions include the ��Ƶ, the Observatories of the Carnegie Institution for Science, Max-Planck-Institut für Astrophysik, Anton Pannekoek Institute for Astronomy, Dunlap Institute for Astronomy & Astrophysics and Steward Observatory.

In search of other worlds: Astronomer explores how planets form and evolve

siddiq22 — Thu, 20 Jul 2023 19:16:57 +0000

In search of other worlds: Astronomer explores how planets form and evolve

siddiq22 Thu, 07/20/2023 - 15:16

Cutline

(photo by rbkomar/Getty Images)

Dan Falk

Topic

Planets

Research & Innovation

Solar System

��Ƶ Mississauga

Subheadline

Assistant Professor Marta Bryan is studying the properties of exoplanets to better understand how our planet and species fit into the larger universe

It wasn’t that long ago that astronomers only knew of eight planets (nine before Pluto’s demotion back in 2006) – those here in our own solar system. Now we know of nearly 10,000 planets orbiting stars beyond our sun – known as exoplanets – and that flood of new worlds has ushered in something of a golden age for planetary scientists.

For astronomers like Marta Bryan, an assistant professor at the ��Ƶ Mississauga and in the David A. Dunlap department of astronomy and astrophysics in the Faculty of Arts & Science, it means there’s no better time to be studying these distant worlds.

“This is such a dynamic field,” says Bryan, who joined U of T in January after four years as a postdoctoral researcher at the University of California, Berkeley. Studying the properties of exoplanets provides “a unique opportunity to put ourselves and our world in the broadest of contexts – how does our solar system, our planet and our species fit into our universe?”

Bryan, who specializes in the study of planetary formation and evolution, was recently awarded the Annie Jump Cannon Award from the American Astronomical Society for her work on exoplanets.

As the tally of exoplanets began to grow, astronomers noticed how diverse planetary systems appear to be, with planets varying widely in size, composition and surface temperature. Some orbit very close to their host stars, while others follow orbits comparable to the Earth’s, or to the giant outer planets in our solar system.

“We’ve found thousands of exoplanets, with a huge diversity of properties,” Bryan says. “For me, one of the driving goals in the field is to understand where that diversity comes from. What does the process of planet formation and evolution look like?”

Marta Bryan uses a range of observational techniques to detect and characterize gas giant planets outside our solar system to explore how planetary systems form and evolve (photo by Nick Iwanyshyn)

While much research on exoplanets has focused on the search for Earth-like worlds, Bryan is interested in gas giant planets, analogous to Jupiter and Saturn in our own solar system. That’s because their sheer heft means they play an important role in determining how smaller planets in the same system evolve.

As Bryan puts it, gas giant planets “dominate the dynamics” of whatever system they’re in. Which means that learning about gas giants can, in fact, help us understand something about Earth-like planets – worlds whose evolution may have been affected by the presence of these much more massive bodies.

As a result, Bryan says, “gas giant planets are an obvious place to start if we want to understand the physics of planet formation.”

The gas giant planets in our own solar system are thought to have played a crucial role over the past five billion years. Jupiter, for example, is believed to have migrated inward before reversing direction and ending up in its current position. Jupiter’s foray into the inner part of the solar system is thought to have stunted the growth of the inner planets, particularly Mars, by scattering some of the gas and dust that might otherwise have been gravitationally pulled toward the red planet.

“We think that Jupiter and Saturn played a dominant role in the early history of our solar system, helping to shape the formation and evolution of our terrestrial planets,” Bryan says. “As a result, we want to understand in the broader extrasolar context what role gas-giant analogs to Jupiter and Saturn have played in shaping the lives of terrestrial worlds.”

The future looks bright – data from the James Webb Space Telescope is already pouring in. Bryan is especially excited about large, ground-based telescopes with mirrors up to 30 metres across, which are currently being planned. These next-generation telescopes may even reveal “biosignatures” on other worlds – signs of life that can be inferred from the composition of a planet’s atmosphere.

And if astronomers do end up finding conclusive evidence of life beyond our own planet, such a discovery “would definitely be transformational,” Bryan says.

Astronomers discover new link between dark matter and 'clumpiness' of the universe

Christopher.Sorensen — Wed, 28 Jun 2023 17:30:06 +0000

Astronomers discover new link between dark matter and 'clumpiness' of the universe

Christopher.Sorensen Wed, 06/28/2023 - 13:30

Cutline

(image by Volker Springel (Max Planck Institute for Astrophysics) et al)

Chris Sasaki

Topic

Astronomy

Research

Researchers at the ��Ƶ have revealed a theoretical breakthrough that may explain both the nature of invisible dark matter and the large-scale structure of the universe known as the cosmic web.

Their study, published in the Journal of Cosmology and Astroparticle Physics, establishes a new link between these two longstanding problems in astronomy, opening new possibilities for understanding the cosmos.

Keir Rogers (supplied image)

The research suggests that the “clumpiness problem,” which centres on the unexpectedly even distribution of matter on large scales throughout the cosmos, may be a sign that dark matter is composed of hypothetical, ultra-light particles called axions.

The implications of proving the existence of hard-to-detect axions extend beyond understanding dark matter and could address fundamental questions about the nature of the universe itself.

“If confirmed with future telescope observations and lab experiments, finding axion dark matter would be one of the most significant discoveries of this century,” says lead author Keir Rogers, Dunlap Fellow at the Dunlap Institute for Astronomy & Astrophysics in the Faculty of Arts & Science .

“At the same time, our results suggest an explanation for why the universe is less clumpy than we thought – an observation that has become increasingly clear over the last decade or so, and currently leaves our theory of the universe uncertain.”

Dark matter, comprising 85 percent of the universe’s mass, is invisible because it does not interact with light. Scientists study its gravitational effects on visible matter to understand how it is distributed in the universe.

A leading theory proposes that dark matter is made of axions, described in quantum mechanics as “fuzzy” due to their wave-like behaviour. Unlike discrete point-like particles, axions can have wavelengths larger than entire galaxies. This fuzziness influences the formation and distribution of dark matter, potentially explaining why the universe is less clumpy than predicted in a universe without axions.

A computer simulation of a section of the universe with and without axions, showing how the dark matter cosmic web structure is less clumpy if containing axions. For scale, the Milky Way galaxy would sit inside one of the small green dots that are called halos (image by Alexander Spencer London/Alex Laguë)

This lack of clumpiness has been observed in large galaxy surveys, challenging the other prevailing theory that dark matter consists only of heavy, weakly interacting sub-atomic particles called WIMPs. Despite experiments like the Large Hadron Collider, no evidence supporting the existence of WIMPs has been found.

“In science, it’s when ideas break down that new discoveries are made and age-old problems are solved,” Rogers says.

For the study, the research team – led by Rogers and including members of associate professor Renée Hložek’s research group at the Dunlap Institute, as well as from the University of Pennsylvania, the Institute for Advanced Study, Columbia University and King’s College London – analyzed observations of relic light from the Big Bang, known as the Cosmic Microwave Background (CMB), obtained from prior telescope surveys.

The researchers compared these CMB data with galaxy clustering data from the Baryon Oscillation Spectroscopic Survey (BOSS), which maps the positions of approximately a million galaxies in the nearby universe. By studying the distribution of galaxies, which mirrors the behaviour of dark matter under gravitational forces, they measured fluctuations in the amount of matter throughout the universe and confirmed its reduced clumpiness compared to predictions.

A map of galaxies in the local universe as seen by the Sloan Digital Sky Survey, which the researchers used to test the axion theory. Each dot is the position of a galaxy and the Earth sits in the middle of the map
(image courtesy Sloan Digital Sky Survey)

The researchers then conducted computer simulations to predict the appearance of relic light and the distribution of galaxies in a universe with long dark matter waves. These calculations aligned with CMB data from the Big Bang and galaxy clustering data, supporting the notion that fuzzy axions could account for the clumpiness problem.

Future research will involve large-scale surveys to map millions of galaxies and provide precise measurements of clumpiness, including observations over the next decade with the Rubin Observatory. The researchers hope to compare their theory to direct observations of dark matter through gravitational lensing – an effect where dark matter clumpiness is measured by how much it bends the light from distant galaxies, akin to a giant magnifying glass. They also plan to investigate how galaxies expel gas into space and how this affects the dark matter distribution to further confirm their results.

Understanding the nature of dark matter is one of the most pressing fundamental questions and key to understanding the origin and future of the universe.

Presently, scientists do not have a single theory that simultaneously explains gravity and quantum mechanics – a theory of everything. The most popular theory of everything over the last few decades is string theory, which posits another level below the quantum level, where everything is made of string-like excitations of energy. According to Rogers, detecting a fuzzy axion particle could be a hint that the string theory of everything is correct.

“We have the tools now that could enable us to finally understand something experimentally about the century-old mystery of dark matter, even in the next decade or so – and that could give us hints to answers about even bigger theoretical questions,” Rogers says.

“The hope is that the puzzling elements of the universe are solvable.”

Astronomers double number of known 'repeating fast radio bursts' using new data tools

Christopher.Sorensen — Mon, 01 May 2023 15:35:57 +0000

Astronomers double number of known 'repeating fast radio bursts' using new data tools

Christopher.Sorensen Mon, 05/01/2023 - 11:35

Cutline

An artist’s impression of the CHIME telescope, used by researchers from the CHIME/FRB Collaboration in detecting flashes of radio waves known as 'fast radio bursts' (illustration by CHIME/FRB Collaboration, with artistic additions by Luka Vlajić)

Meaghan MacSween

Topic

Astronomy

Global

Research

Astronomers in the Canadian-led CHIME/FRB Collaboration – including researchers from the ��Ƶ – have doubled the number of known repeating sources of mysterious flashes of radio waves, known as fast radio bursts (FRBs). Through the discovery of 25 new repeating sources (for a total of 50), the team has also solidified the idea that all FRBs may eventually repeat.

FRBs are considered one of the biggest mysteries in astronomy, but their exact origins are unknown.

Astronomers do know that they come from far outside of our Milky Way, and are likely produced by the cinders left behind after stars die. Most of the thousands of FRBs that astronomers have discovered to date have only ever been seen to burst once, but there is a small subset that have been seen to burst multiple times.

One of the big questions is whether the repeating FRBs, and those that don’t repeat, have similar origins. One key clue is that the two populations seem to have different characteristics – such as the durations of the bursts they produce and the range of frequencies emitted. This has led to the consensus that there are possibly two distinct categories of FRBs: repeaters and one-offs, with different origins.

Finding more repeating sources is key to answering this question – and in new research published in the Astrophysical Journal, the CHIME/FRB Collaboration presents 25 new sources. While the team had previously established repeating FRBs as a class of sources, this is the first time they have combed through the data to find every repeating source detected so far, including the less obvious ones. To make this happen, the group developed a new set of statistics tools.

The CHIME telescope in Penticton, B.C. (photo by Andre Renard/CHIME/FRB Collaboration)

“We can now accurately calculate the probability that two or more bursts coming from similar locations are not just a coincidence,” explains Ziggy Pleunis, a Dunlap postdoctoral fellow at the Dunlap Institute for Astronomy & Astrophysics and corresponding author of the publication. “These new tools were essential for this study, and will also be very useful for similar research going forward.”

Thanks to radio telescopes like the Canadian Hydrogen Intensity Mapping Experiment (CHIME), the number of detected FRBs has grown from less than a hundred to thousands in recent years due to CHIME’s capacity to scan the entire northern sky every day.

“That’s how CHIME has an edge over other telescopes when it comes to discovering FRBs,” Pleunis says.

In their new research, the CHIME/FRB Collaboration has demonstrated that many repeating FRBs are surprisingly inactive, producing less than one burst per week of observing time.

“Many apparently one-off FRBs have simply not yet been observed long enough for a second burst from the source to be detected,” Pleunis explains.

Repeating sources of FRBs are uniquely valuable to astronomers. First, knowing that a source is a repeater creates an opportunity to observe that same source with other telescopes in more detail. Secondly, more bursts offer more information on the diversity of emission that a source can produce.

“It is exciting that CHIME/FRB saw multiple flashes from the same locations, as this allows for the detailed investigation of their nature,” says Adaeze Ibik, a PhD student in the David A. Dunlap department of astronomy and astrophysics in the Faculty of Arts & Science.

Ibik has led the search for the galaxies in which some of the newly identified repeating FRBs are embedded, as reported in an accompanying research publication currently under review. “We were able to hone in on some of these repeating sources and have already identified likely associated galaxies for two of them.”

Pleunis notes that this new discovery brings astronomers closer to understanding what FRBs are – leading to even further-reaching implications.

“FRBs are likely produced by the leftovers from explosive stellar deaths.” Pleunis says. “By studying repeating FRB sources in detail, we can study the environments that these explosions occur in and better understand the end stages of a star’s life.”

“We can also learn more about the material that’s being expelled before and during the star’s demise, which is then returned to the galaxies that the FRBs live in.”

The CHIME project is co-led by the University of British Columbia, McGill University, ��Ƶ and the Dominion Radio Astrophysical Observatory, with collaborating institutions across North America.

CHIME’s research is funded by the Canadian Foundation for Innovation’s Leading Edge Fund, by contributions from the province of British Columbia and Quebec, and by U of T’s Dunlap Institute for Astronomy and Astrophysics, among other sources.

First space images captured by balloon-borne telescope

siddiq22 — Fri, 21 Apr 2023 13:34:16 +0000

First space images captured by balloon-borne telescope

siddiq22 Fri, 04/21/2023 - 09:34

Cutline

A false-colour image of the “Tarantula Nebula” taken in visible and ultraviolet light by the SuperBIT telescope shortly after launch (image courtesy of SuperBIT)

Topic

Astronomy

Astrophysics

Faculty of Arts & Science Staff

Faculty & Staff

Graduate Students

Research

Astronomers have successfully launched a balloon-borne telescope that has begun capturing images of the universe on its first flight above the Earth’s atmosphere.

The Super Pressure Balloon-Borne Imaging Telescope (SuperBIT) was flown to the edge of space by a helium-filled NASA scientific balloon the size of a football stadium. There, it will help researchers investigate the mystery of dark matter.

SuperBIT has already taken its first images on this flight, showing the “Tarantula Nebula” – a bright cluster of gas and dust in a galaxy neighbourhood near our Milky Way – and the collision between the two galaxies NGC 4038 and NGC 4039, known as “the Antennae.”

SuperBIT is a collaboration between the ��Ƶ, Princeton University, Durham University and NASA.

“A dedicated team of students developing one of the world’s great telescopes – it’s inspiring,” says Barth Netterfield, a professor in U of T's David A. Dunlap department of astronomy and astrophysics and the department of physics in the Faculty of Arts & Science, and an associate at the Dunlap Institute for Astronomy and Astrophysics.

“After a decade of tremendous effort, we are getting these exquisite images with a wide range of science goals, which will help us to better understand the universe.”

A false-colour image taken by the SuperBIT telescope shows of a pair of galaxies smashing into each other (image courtesy of SuperBIT)

The balloon aunched from Wānaka, New Zealand earlier this week, following a two-year delay due to the COVID pandemic.

Carried by seasonally stable winds for about three months, SuperBIT will circumnavigate the southern hemisphere several times – imaging the sky all night, then using solar panels to recharge its batteries during the day.

SuperBIT flies at an altitude of 33.5 kilometres, above 99.5 per cent of the Earth’s atmosphere. It takes high-resolution images like those from the Hubble Space Telescope, but with a much wider field of view.

The scientific goal for the first flight is to measure the properties of dark matter, a heavy but invisible type of material.

SuperBIT will test whether dark-matter particles can bounce off each other, by mapping the dark matter around clusters of galaxies that are colliding with neighbouring galaxy clusters.

The SuperBIT telescope in New Zealand prior to the launch (photo courtesy of Columbia Scientific Balloon Facility)

Various theories suggest that some dark matter might either slow down, spread out, or get chipped off during a collision.

Although dark matter is invisible, SuperBIT will map where it is by the way it bends passing rays of light – a technique known as gravitational lensing.

While telescopes on the ground must squint through the Earth’s atmosphere – meaning their view can become blurred – space-based telescopes get a clear view of the light that has travelled billions of years from the distant universe.

Members of the SuperBIT team prepare for a flight test (photo courtesy of SuperBIT)

SuperBIT is the first balloon-borne telescope capable of taking wide-field images – its sharpness of vision is not affected by the atmosphere, but only by the laws of optics.

During its final test flight in 2019, SuperBIT demonstrated extraordinary pointing stability.

“Imagine you’re trying to thread a needle that’s 2.5 kilometres away – so roughly 30 city blocks,” explains Emaad Paracha, a PhD candidate in the department of physics.

“SuperBIT has the ability to point to the exact spot you’d need that needle to be thread, while keeping that thread from touching the sides of the needle for up to 60 minutes.”

SuperBIT cost about US$5 million – almost 1,000 times less than an equivalent satellite. Not only is helium cheaper than rocket fuel, but the ability of SuperBIT to return to Earth via parachute meant the team could tweak its design over several test flights.

“A successful SuperBIT launch paves the way to a future in which individual academic institutions are able to design, develop and operate world-class space instruments at a low cost, while also providing the training opportunity for instrument development and data analysis for the students,” says Ajay Gill, a PhD candidate at the David A. Dunlap department of astronomy and astrophysics and the Dunlap Institute.

SuperBIT can also be upgraded on a regular basis. For example, the development team buys a new camera shortly before each launch, because modern detectors are improving so rapidly.

The team already has funding to upgrade SuperBIT’s 0.5-metre telescope to 1.6 metres, which would boost light gathering power tenfold, with a wider-angle lens and more megapixels.

The relatively cheap cost may even make it possible for a fleet of balloon-borne telescopes to offer time to astronomers around the world. Interested members of the public can track SuperBIT's flight status on NASA's website.

The mission was funded by NASA, the Canadian Space Agency, the Royal Society and U of T's Dunlap Institute for Astronomy and Astrophysics.

With notes from Meaghan MacSween

Add new author/reporter

Leighton Kitson

Canadian researchers will have access to next-generation radio astronomy observatory

Christopher.Sorensen — Fri, 27 Jan 2023 15:10:58 +0000

Canadian researchers will have access to next-generation radio astronomy observatory

Christopher.Sorensen Fri, 01/27/2023 - 10:10

Cutline

A composite image of the future SKAO telescopes co-located in Australia and South Africa, blending what already exists on site with artists’ impressions (photo courtesy of SKAO)

Topic

Global Lens

Leah Cowen

Global

Research & Innovation

Canada intends to proceed to full membership in the Square Kilometre Array Observatory (SKAO), a next-generation radio astronomy observatory bringing together nations from around the world to build and operate cutting-edge radio telescopes.

SKAO will operate two telescopes – one in Australia and one in South Africa – with headquarters in the United Kingdom. The facility will enable discoveries that will advance our understanding of the universe, the fundamental laws of physics and the prospects for life on other planets. Membership in the SKAO will allow Canada to develop strong scientific, technical and industrial capabilities and collaborations well into the future.

The decision to proceed with full membership, announced this week by Innovation, Science and Industry Minister François‑Philippe Champagne, is expected to provide Canadian astronomers with a six per cent use-share of the SKAO and support establishing a domestic regional centre. The centre will provide direct connections to data collected with the SKA telescopes and science support to enable ground-breaking discoveries.

Bryan Gaensler

“This is tremendously exciting news,” says Bryan Gaensler, director of the ��Ƶ’s Dunlap Institute for Astronomy & Astrophysics in the Faculty of Arts & Science and former science director of the Canadian Square Kilometre Array, a global radio observatory. “Canadian membership in the SKAO was one of the marquee priorities in the Canadian Astronomy Long Range Plan for 2020-2030. Membership will open new opportunities for ��Ƶ leadership at an international scale.”

With full membership, U of T envisages significant involvement in a Canadian SKA Regional Centre as part of its recently established Data Sciences Institute.

“The SKAO is a key part of U of T’s Strategic Research Plan for 2018 - 2023 and an important institutional priority,” says Leah Cowen, U of T’s vice-president, research and innovation, and strategic initiatives. “It is a brilliant example of a high-impact, interdisciplinary research collaboration that is a reflection of our incredible research community.”

U of T also leads the $10-million Canadian Initiative for Radio Astronomy Data Analysis (CIRADA), a consortium of six Canadian universities, the National Research Council Canada and many international partners, whose goal is to establish Canadian capability for processing, archiving and sharing the enormous scientific data sets anticipated for the SKA.

“I’m thrilled to congratulate everyone at U of T for their work over many years in bringing us to this historic commitment,” says Melanie Woodin, dean of the Faculty of Arts & Science. “It’s rewarding to know that the SKAO involves researchers from five Arts & Science units: the Dunlap Institute, the David A. Dunlap Department of Astronomy & Astrophysics, the Canadian Institute for Theoretical Astrophysics, the Department of Physics and the Department of Statistical Sciences.”

The initial phase of the SKAO consists of 197 radio dishes located in South Africa and 131,072 antennas located in Australia. Construction on Phase 1 began in June 2021 and is expected to be completed by 2029.

Canada was one of six founding members of the initial SKAO consortium in 2000 and has maintained substantial involvement and engagement in the SKAO project to date. Canadian astronomers are playing leading roles in designing marquee SKA science programs – including tests of gravity, low-frequency cosmology, cosmic magnetism, dark energy and detecting transient systems. They have multi-wavelength expertise in galaxy evolution, multi-messenger astronomy and planetary system formation.

“Canada's commitment to the SKA secures our position at the forefront of astrophysics for the next few decades. Everybody at U of T that has the slightest interest in astronomy should prepare to get absolutely blown away by what the SKA is going to find,” says Roberto Abraham, chair of the David A. Dunlap department of astronomy and astrophysics. “And what makes it extra exciting is that U of T's leadership in the national consortium means that many of the most amazing discoveries will get made right here. What an exciting time to be an astronomer. To all the young people just getting into the subject: Hold on to your hats – it's going to be a wild ride!”

As well as working on many aspects of the SKA project itself, Canadian astronomers are developing a variety of new facilities and experiments aimed at testing the technology needed for the SKAO. Foremost amongst these is the Canadian Hydrogen Intensity Mapping Experiment (CHIME) of which U of T is a member. CHIME is a unique radio telescope that can detect fast radio bursts and is making a three-dimensional map of the dark energy that is accelerating the expansion of the universe.

The NRC points out that for the SKAO, respecting Indigenous cultures and the local populations has been a key consideration from the start: “These core principles are fully aligned with the priorities of the Canadian astronomical community as expressed in the Canadian Astronomy Long Range Plan 2020-2030.”

A night of big ideas: Celebrating 50 years of the Connaught Fund at U of T

mattimar — Mon, 12 Dec 2022 19:15:26 +0000

A night of big ideas: Celebrating 50 years of the Connaught Fund at U of T

mattimar Mon, 12/12/2022 - 14:15

Cutline

From left: Renée Hložek, Maydianne Andrade and Ronald Deibert discuss the importance of university research and the next big ideas to influence our society, with journalist Mary Ito (all photos by Polina Teif)

Mariam Matti

Topic

Department of Biological Sciences

Leah Cowen

Vice-president of Research and Innovation and Strategic Initiatives

Munk School of Global Affairs & Public Policy

Citizen Lab

Connaught Fund