Meaghan MacSween

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

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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

Breaking Research

Astronomy

Astronomy & Astrophysics

Dunlap Institute for Astronomy & Astrophysics

Faculty of Arts & Science

Global

Research

Space

Astronomers in the Canadian-led CHIME/FRB Collaboration – including researchers from the University of Toronto – 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, University of Toronto 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 �山ǿ��’s Dunlap Institute for Astronomy and Astrophysics, among other sources.

Fast radio bursts used as 'searchlights' to detect gas in Milky Way

Christopher.Sorensen — Thu, 30 Mar 2023 15:21:10 +0000

Fast radio bursts used as 'searchlights' to detect gas in Milky Way

Christopher.Sorensen Thu, 03/30/2023 - 11:21

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By tracking fast radio bursts, �山ǿ�� PhD candidate Amanda Cook and her colleagues discovered that the Milky Way’s halo contains much less gas than previous models had predicted (photo courtesy of Amanda Cook)

Meaghan MacSween

Topic

Breaking Research

Dunlap Institute for Astronomy & Astrophysics

Faculty of Arts & Science

Milky Way

Research & Innovation

Space

University of Toronto researcher Amanda Cook has found a way to use bright signals coming from across the universe to weigh the atmosphere of the Milky Way galaxy.

The radio signals she used come from the astronomical phenomenon known as fast radio bursts (FRBs) – enigmatic celestial objects that generate brief flashes of radio waves and are considered one of the biggest mysteries in astronomy.

Since an FRB simultaneously generates both high frequency radio waves (the equivalent of blue light) and low frequency radio waves (the equivalent of redlight), the different colours of radio waves might be expected to arrive at a telescope at the same time. But that’s not what happens. As an FRB passes through gas, it slows down – more so for the high frequencies than the low frequencies. The result is a delay between the different frequencies or colours reaching our telescope, effectively smearing the radio burst’s signal out in time.

Astronomers like Cook call this smearing “dispersion” and are able to use it as a tool to detect otherwise invisible gas throughout the cosmos.

“Using smearing to study the universe is like using your home heating bill to work out what the weather must have been like over the winter,” says Cook, who is a PhD candidate in the David A. Dunlap department of astronomy and astrophysics, and the Dunlap Institute for Astronomy & Astrophysics, in the Faculty of Arts & Science. “In the same way that your heating bill tells you whether it was a harsh winter or a mild winter – but not what the temperature was like on any individual date – the smearing that we see allows us to infer the total amount of material that the FRB signal has encountered on its journey from the FRB to Earth. It just can’t tell us how that material was distributed along the way.”

“The key thing is that regardless of how gas in front of the FRB is distributed, an FRB signal that is smeared more by the time it reaches our telescopes must be produced by an FRB that is farther away in the same way that an expensive heating bill must have meant a cold winter overall.”

An illustration of a radio signal from a fast radio burst as it moves toward telescopes on Earth (image courtesy of J. Josephides/Swinburne University of Technology, with minor edits from the Dunlap Institute)

In this case, Cook used the dispersion method to measure how much gas is present in the Milky Way’s halo – an “atmosphere” of the Milky Way that extends outwards by around a half a million light-years in all directions.

Using FRB signals collected by the Canadian Hydrogen Intensity Mapping Experiment (CHIME) radio telescope, Cook and her team discovered that the Milky Way’s halo contains much less gas than previous models had predicted. The results were published in the Astrophysical Journal in a study titled, “An FRB Sent Me a DM.”

Though there had been earlier studies applying related techniques, this is the first time that the halo’s gas has been measured using a large uniform sample of FRBs – thanks to the CHIME telescope.

The team used FRB signals at different distances from Earth to get the result. Cook likens this approach to trying to work out the average driving distance from different Canadian border crossings to Toronto by having friends from different American states drive to Toronto, telling you only the total distance they drove. The information from your Texan friend is not going to be particularly useful, but the experience from your Michigan and New York friends may be far more insightful. And if you have friends that live right on the border, in Buffalo or Detroit, then their answers will pretty much give you the information you need.

Cook and her supervisor, Professor Bryan Gaensler, have been working on this research since she was a first-year graduate student. “It ended up being a lot more difficult than we thought,” Cook says.

Difficult enough, that she, Gaensler and their colleagues actually stepped outside of conventional astronomical models. They turned to researchers in an entirely different field – statistics – and asked those colleagues for a new set of methods to apply to their approach.

“This is an exciting new way of studying our Milky Way,” says Gaensler, who is also an author on the publication. “We’re still trying to figure out what fast radio bursts actually are, but in the meantime we can use them as searchlights to study things much closer to home.”

Cook and Gaensler note that FRB signals could be used to study the structure of everything that the FRB signal passes through on its long journey, including the material between galaxies, the halos of other galaxies and the gas inside of galaxies.

Meanwhile, many more FRB discoveries are anticipated. With even more data, Cook and her team hope to create a 3D map of the Milky Way halo. “Each FRB gives us a measurement of the Milky Way halo in one direction, so as we continue to collect them, we can build up a detailed picture,” Cook says.

Beyond that, she notes that these clues contribute to our understanding of the early universe.

“Improving our knowledge of the Milky Way halo helps us learn about the formation of our galaxy as a whole.”

�山ǿ�� undergrad develops AI tool to accelerate the search for alien life

Christopher.Sorensen — Mon, 30 Jan 2023 15:37:17 +0000

�山ǿ�� undergrad develops AI tool to accelerate the search for alien life

Christopher.Sorensen Mon, 01/30/2023 - 10:37

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Peter Ma, a member of Victoria College, developed an AI algorithm used by an international group of researchers to help speed up the search for signals generated by extraterrestrial life (photo by Polina Teif)

Meaghan MacSween

Topic

Breaking Research

Dunlap Institute for Astronomy & Astrophysics

Faculty of Arts & Science

Research & Innovation

Space

Victoria College

Are we alone in the universe? With the help of artificial intelligence, scientists may be one step closer to finding the answer.

Led by researchers at the University of Toronto, an international team of scientists has streamlined the search for extraterrestrial life by using a new algorithm to organize the data from their telescopes into categories to distinguish between real signals and interference. Through an AI process known as machine learning, the new approach allows the researchers to quickly sort through the information and find patterns.

Since the 1960s, astronomers working on “SETI” (the Search for Extraterrestrial Intelligence) have used powerful radio telescopes to search thousands of stars and hundreds of galaxies for so-called “technosignatures,” or technologically-generated signals, on the assumption that an advanced extraterrestrial civilization would be sophisticated enough to emit such signals. Yet, despite the fact that the telescopes used for these searches are located in areas where there is minimal interference from technology like cell phones and TV stations, human disturbance still poses major challenges.

“In many of our observations, there is a lot of interference,” says Peter Ma, a U of T undergraduate student studying math and physics in the Faculty of Arts & Science who is first author on a new research paper published in Nature Astronomy that explains the technique.

“We need to distinguish the exciting radio signals in space from the uninteresting radio signals from Earth.”

By simulating signals of both types, the team has trained their machine-learning tools to differentiate between extraterrestrial-like signals and human-generated interference. They compared a range of different machine-learning algorithms, studied their precision and false-positive rates and then used that information to settle on a powerful algorithm.

This new algorithm, created by Ma, has resulted in the discovery of eight new radio signals that could potentially be transmissions from extraterrestrial intelligence. The signals came from five different stars located 30 to 90 light years from Earth. The signals were overlooked in a previous analysis of the same data, which did not use machine learning.

To the SETI team, these signals are considered notable for two reasons. “First, they are present when we look at the star and absent when we look away – as opposed to local interference, which is generally always present,” says Steve Croft, project scientist for Breakthrough Listen on the Green Bank Telescope. “Second, the signals change in frequency over time in a way that makes them appear far from the telescope.”

However, Croft notes that when you have a dataset containing millions of signals, signals can occasionally have the same two characteristics just by sheer chance. “It’s a bit like walking across a gravel path and finding a stone stuck in the tread of your shoe that seems to fit perfectly.”

For this reason, even though the eight signals appear the way the team expects extraterrestrial signals to look, the researchers are not yet convinced that they are from extraterrestrial intelligence – at least until they see the same signal again. When brief follow-up observations were done using the Green Bank Radio Telescope, the patterns that could indicate extraterrestrial signals were not found. More observations and analyses are underway.

A member of Victoria College, Ma refers to the algorithm that he created as a combination of two subtypes of machine learning – supervised learning and unsupervised learning. Called “semi-unsupervised learning,” his approach involves using supervised techniques to guide and train the algorithm in order to help it generalize, along with unsupervised learning techniques, so that new hidden patterns can be more easily discovered in the data.

Ma first came up with the idea to apply this specific algorithm to the search for extraterrestrial intelligence in a Grade 12 computer science class. Unfortunately, he says, the project confused his teachers, who weren’t sure how it could be used.

“I only told my team after the paper’s publication that this all started as a high-school project that wasn’t really appreciated by my teachers,” Ma says.

Cherry Ng, a research associate at �山ǿ��’s Dunlap Institute for Astronomy and Astrophysics and second author on the paper, says new ideas are very important in a field like SETI. “By poking the data with every technique, we might be able to discover exciting signals,” she says.

Ng, who has been working on this project with Ma since the summer of 2020, says machine learning is the way to go in an era of big data astronomy. “I am impressed by how well this approach has performed on the search for extraterrestrial intelligence,” Ng says.

“With the help of artificial intelligence, I’m optimistic that we’ll be able to better quantify the likelihood of the presence of extraterrestrial signals from other civilizations.”

Looking ahead, Ma, Ng, and the rest of the SETI team hope to expand on their new algorithm and apply it to other datasets and observatories.

Using powerful, multi-antenna radio telescopes like MeerKAT, the Square Kilometre Array, and the Next Generation VL, Ma says the team plans to scale their machine learning approach in a major way.

“With our new technique, combined with the next generation of telescopes, we hope that machine learning can take us from searching hundreds of stars to searching millions.”

The data used in this study come from the Green Bank Telescope in West Virginia, which is one of the major facilities involved in the Breakthrough Listen technosignature search project. The initiative, sponsored by the Breakthrough Prize Foundation, is the most powerful, comprehensive and intensive scientific search ever undertaken for signs of intelligent life beyond Earth.

Researchers study Milky Way's 'feeding habits' in search of clues about its origins

Christopher.Sorensen — Tue, 11 Jan 2022 17:01:10 +0000

Researchers study Milky Way's 'feeding habits' in search of clues about its origins

Christopher.Sorensen Tue, 01/11/2022 - 12:01

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(Photo by Bill Ingalls/ NASA via Getty Images)

Meaghan MacSween

Topic

Breaking Research

Dunlap Institute for Astronomy & Astrophysics

Faculty of Arts & Science

Global

Milky Way

Research & Innovation

Space

Astronomers are one step closer to revealing the properties of dark matter enveloping our Milky Way galaxy thanks to a new map of 12 streams of stars orbiting within our galactic halo.

Understanding these star streams is very important for astronomers. As well as revealing the dark matter that holds the stars in their orbits, they also tell us about the formation history of the Milky Way, revealing that the galaxy has steadily grown over billions of years by shredding and consuming smaller stellar systems.

“We are seeing these streams being disrupted by the Milky Way’s gravitational pull, and eventually becoming part of the Milky Way,” said Ting Li, an assistant professor in the David A. Dunlap department of astronomy and astrophysics in the University of Toronto’ Faculty of Arts & Science.

Li is the lead author of a new paper (preprint available here) that has been accepted for publication in the American Astronomical Society’s Astrophysical Journal.

“This study gives us a snapshot of the Milky Way’s feeding habits, such as what kinds of smaller stellar systems it ‘eats,’ Li says. “As our galaxy is getting older, it is getting fatter.”

Li and her international team of collaborators initiated a dedicated program – the Southern Stellar Stream Spectroscopic Survey (S5) – to measure the properties of stellar streams: the shredded remains of neighbouring small galaxies and star clusters that are being torn apart by the Milky Way.

They are the first group of scientists to study such a rich collection of stellar streams, measuring the speeds of stars using the Anglo-Australian Telescope (AAT), a four-metre optical telescope in Australia. Li and her team used the Doppler shift of light to find out how fast individual stars are moving.

Unlike previous studies that have focused on one stream at a time, “S5 is dedicated to measuring as many streams as possible, which we can do very efficiently with the unique capabilities of the AAT,” says co-author Associate Professor Daniel Zucker of Macquarie University.

The properties of stellar streams reveal the presence of the invisible dark matter of the Milky Way.

“Think of a Christmas tree,” says co-author Professor Geraint Lewis of the University of Sydney. “On a dark night, we see the Christmas lights, but not the tree they are wrapped around. But the shape of the lights reveals the shape of the tree. It is the same with stellar streams – their orbits reveal the dark matter.”

A crucial ingredient for the success of S5 were observations from the European Gaia space mission. “Gaia provided us with exquisite measurements of positions and motions of stars – essential for identifying members of the stellar streams,” says Sergey Koposov, reader in observational astronomy in the University of Edinburgh and a co-author of the study.

As well as measuring their speeds, the astronomers can use these observations to work out the chemical compositions of the stars, telling us where they were born.

“Stellar streams can come either from disrupting galaxies or star clusters,” says Assistant Professor Alex Ji at the University of Chicago, a co-author on the study. "These two types of streams provide different insights into the nature of dark matter."

Li says the new observations are essential for determining how our Milky Way arose from the featureless universe after the Big Bang.

“For me, this is one of the most intriguing questions – a question about our ultimate origins,” Li says. “It is the reason why we founded S5 and built an international collaboration to address this”.

Li’s team plans to produce more measurements on stellar streams in the Milky Way. In the meantime, she is pleased with these results as a starting point.

“Over the next decade, there will be a lot of dedicated studies looking at stellar streams,” Li says. “We are trailblazers and pathfinders on this journey. It is going to be very exciting.”

�山ǿ�� astronomer's research suggests 'magnetic tunnel' surrounds our solar system

Christopher.Sorensen — Fri, 15 Oct 2021 19:05:24 +0000

�山ǿ�� astronomer's research suggests 'magnetic tunnel' surrounds our solar system

Christopher.Sorensen Fri, 10/15/2021 - 15:05

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Jennifer West, a researcher at �山ǿ��'s Dunlap Institute for Astronomy & Astrophysics, says two magnetic structures seen on opposite sides of the sky form what looks like a tunnel around the solar system (photo courtesy of Jennifer West)

Meaghan MacSween

Topic

Our Community

Dunlap Institute for Astronomy & Astrophysics

Faculty of Arts & Science

Research & Innovation

A University of Toronto astronomer’s research suggests the solar system is surrounded by a magnetic tunnel that can be seen in radio waves.

Jennifer West, a research associate at the Dunlap Institute for Astronomy & Astrophysics, is making a scientific case that two bright structures seen on opposite sides of the sky – previously considered to be separate – are actually connected and are made of rope-like filaments. The connection forms what looks like a tunnel around our solar system.

The data results of West’s research have been published in the Astrophysical Journal.

“If we were to look up in the sky,” says West, “we would see this tunnel-like structure in just about every direction we looked – that is, if we had eyes that could see radio light.”

Called “the North Polar Spur” and “the Fan Region,” astronomers have known about these two structures for decades, West says. But most scientific explanations have focused on them individually. West and her colleagues, by contrast, believe they are the first astronomers to connect them as a unit.

Made up of charged particles and a magnetic field, the structures are shaped like long ropes, and are located about 350 light-years away from us – and are about 1,000 light-years long.

“That’s the equivalent distance of travelling between Toronto and Vancouver two trillion times,” West says.

Left: A curving tunnel, with lines formed by the tunnel lights and road lane markers, forms a similar geometry to the proposed model of the North Polar Spur and Fan Region (photo by Pixabay/ illustration by Jennifer West). Right: The sky as it would appear in radio polarized waves (image by Dominion Radio Astrophysical Observatory/Villa Elisa telescope/ESA/Planck Collaboration/Stellarium/Jennifer West)

West has been thinking about these features on and off for 15 years – ever since she first saw a map of the radio sky. More recently, she built a computer model that calculated what the radio sky would look like from Earth as she varied the shape and location of the long ropes. The model allowed West to “build” the structure around us, and showed her what the sky would look like through our telescopes. It was this new perspective that helped her to match the model to the data.

“A few years ago, one of our co-authors, Tom Landecker, told me about a paper from 1965 – from the early days of radio astronomy,” West says. “Based on the crude data available at this time, the authors [Mathewson and Milne], speculated that these polarized radio signals could arise from our view of the Local Arm of the galaxy, from inside it.

“That paper inspired me to develop this idea and tie my model to the vastly better data that our telescopes give us today.”

Illustrated map of Milky Way Galaxy shown with the position and size of proposed filaments. Inset shows a more detailed view of the Local environments, and the position of Local Bubble and various nearby dust clouds (image by NASA/JPL-Caltech/R. Hurt/SSC/Caltech with annotations by Jennifer West)

West uses the Earth’s map as an example. The North pole is on the top and the equator is through the middle – unless you re-draw the map from a different perspective. The same is true for the map of our galaxy. “Most astronomers look at a map with the North pole of the galaxy up and the galactic centre in the middle,” West explains. “An important part that inspired this idea was to remake that map with a different point in the middle.”

“This is extremely clever work,” says Bryan Gaensler, a professor at the Dunlap Institute and an author of the publication. “When Jennifer first pitched this to me, I thought it was too ‘out-there’ to be a possible explanation. But she was ultimately able to convince me. Now, I’m excited to see how the rest of the astronomy community reacts.”

An expert in magnetism in galaxies and the interstellar medium, West looks forward to the more possible discoveries connected to this research.

“Magnetic fields don’t exist in isolation,” she says. “They all must to connect to each other. So, a next step is to better understand how this local magnetic field connects both to the larger-scale galactic magnetic field, and also to the smaller scale magnetic fields of our sun and Earth.”

In the meantime, West agrees that the new “tunnel” model not only brings new insight to the science community, but also a ground-breaking concept for the rest of us.

“I think it’s just awesome to imagine that these structures are everywhere whenever we look up into the night sky.”

�山ǿ�� astronomy course gazes at the stars through an Indigenous lens

Christopher.Sorensen — Tue, 14 Sep 2021 19:15:10 +0000

�山ǿ�� astronomy course gazes at the stars through an Indigenous lens

Christopher.Sorensen Tue, 09/14/2021 - 15:15

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The Milky Way is captured with an hour-long time exposure over Osoyoos, B.C (photo by Preserved Light Photography via Getty Images)

Meaghan MacSween

Topic

Our Community

Dunlap Institute for Astronomy & Astrophysics

Indigenous

A new course at the University of Toronto offers students the opportunity to learn about astronomy through the lens of Indigenous knowledges – particularly those of Indigenous Peoples from Turtle Island.

Hilding Neilson

Hilding Neilson, an assistant professor at the David A. Dunlap department of astronomy and astrophysics in the Faculty of Arts & Science, created the third-year course called “Indigenous Worldviews & Astronomy” for students who are interested in Indigenous perspectives, ethics and colonization in science.

Neilson, a Mi’kmaw from the Qalipu First Nation, says he believes viewing astronomy exclusively through a Western lens can be limiting.

“We tend to omit Indigenous perspectives and methods in this discussion, even though we live and benefit from being on Indigenous lands,” says Neilson, whose own research focuses on massive star evolution, atmospheres, stellar pulsation, stellar winds, binarity, convection, exoplanets and planet-hosting stars.

“By embracing Indigenous and other knowledges, we bring more lenses – and that can only enrich our view and understanding of the universe.”

Neilson describes Indigenous knowledges as more holistic and relational, reflecting our place on the land and our relation to the world around us.

He compares the inclusion of Indigenous knowledges to an astronomer that uses infrared and ultraviolet telescopes in addition to traditional optical telescopes – and therefore is able to understand far more about the night sky.

The class will teach students about the intersection of western astronomy and ongoing colonization so they can better understand the responsibilities of Western astronomers when it comes to respecting treaties and Indigenous rights, the course description says. It will also present students with an Indigenous lens regarding space exploration.

While Mi'kmaq culture wasn’t a large part of his life growing up, Neilson says he was inspired by a lecture delivered by a Cree astronomer and decided to learn more as a result.

“I feel that learning from Indigenous knowledges have allowed me to relate and connect with the science more deeply, and to think about how I myself relate to that knowledge,” Neilson says.

“It has made me a better scientist.”

CHIME study involving �山ǿ�� astronomers finds fast radio bursts repeat 'on the time scale of weeks'

Christopher.Sorensen — Mon, 22 Jun 2020 15:42:14 +0000

CHIME study involving �山ǿ�� astronomers finds fast radio bursts repeat 'on the time scale of weeks'

Christopher.Sorensen Mon, 06/22/2020 - 11:42

Cutline

The findings, described by �山ǿ�� researcher Dongzi Li as "unexpected," are the first to demonstrate that repeating FRBs can burst predictably (photo courtesy CHIME)

Meaghan MacSween

Topic

Breaking Research

Dunlap Institute for Astronomy & Astrophysics

Faculty of Arts & Science

Graduate Students

Research & Innovation

Space

A Canadian-led team of astronomers, including researchers from the University of Toronto’s Dunlap Institute for Astronomy & Astrophysics, has discovered that a repeating fast radio burst (FRB) originating from a nearby galaxy pulses at regular intervals.

Researchers with the Canadian Hydrogen Intensity Mapping Experiment (CHIME) Fast Radio Burst Collaboration used the CHIME telescope in British Columbia to show that the repeating radio source known as FRB 180916.J0158+65 – first discovered in 2018 by the same group – pulsates every 16.35 days.

The findings, described in a study published recently in Nature, are the first to demonstrate that repeating FRBs can burst predictably.

The finding was unexpected. “We were surprised by the fact that the FRB has regular activity on the time scale of weeks,” said Dongzi Li, a PhD student at Dunlap and corresponding author of the paper. “Most people would expect it to be at much shorter time scales, like seconds or even milliseconds, from rotation of a compact star. Any explanation for a 16-day cycle is likely very different.”

FRBs were discovered over a decade ago. First thought to be singular events, astronomers have since learned that some of these high-intensity blasts of radio emissions, in fact, repeat.

Though the explanation for the mysterious phenomenon is still elusive, the new study is another step towards determining what might be causing FRBs.

“There are suddenly lots of concrete questions to ask and to follow-up on,” explains Li. “If any observed properties of the bursts change regularly with the same 16.35-day period, it will tell us about the environment close to the burst.”

Earlier this year, astronomers in Europe, in partnership with the CHIME/FRB Collaboration, were able to pinpoint FRB 180916 to a nearby galaxy located 500 million light years from Earth. Astronomers worldwide are now studying the source with a variety of telescopes, in the hopes of explaining the repetition.

Two �山ǿ�� researchers named CIFAR Azrieli Global Scholars

noreen.rasbach — Thu, 05 Sep 2019 04:00:00 +0000

Two �山ǿ�� researchers named CIFAR Azrieli Global Scholars

noreen.rasbach Thu, 09/05/2019 - 00:00

Cutline

�山ǿ��'s Jean-Philippe Julien (left) and Renée Hložek were among 14 global researchers named 2019-2021 CIFAR Azrieli Global Scholars

Topic

Dunlap Institute for Astronomy & Astrophysics

Faculty of Arts & Science

Faculty of Medicine

Global

Hospital for Sick Children

Immunology

Research & Innovation

Two University of Toronto faculty members have been named 2019-2021 CIFAR Azrieli Global Scholars, an award recognizing early-career researchers on their way to becoming future research leaders.

Renée Hložek, an assistant professor of astrophysics at the Dunlap Institute for Astronomy & Astrophysics, and Jean-Philippe Julien, an assistant professor in the departments of biochemistry and immunology and a scientist at the Hospital for Sick Children, were among 14 global researchers selected to receive a two-year term in a CIFAR research program and $100,000 in support of their research. Hložek will join CIFAR’s “Gravity and the Extreme Universe” program, while Julien will be part of the “Molecular Architecture of Life" program.

The award, a professional skills development program, also provides mentorship from a senior researcher and skills training.

"We are thrilled about this infusion of talent joining our research programs and our global community,” said Alan Bernstein, CIFAR’s president and CEO. "These early-career scholars and scientists are among the world's brightest and most promising leaders of their generation."

CIFAR is a Canadian-based, global charitable organization that brings together a diverse group of experts from around the world to tackle important questions facing science and humanity.

Hložek studies a variety of problems in theoretical and observational cosmology. Her research focuses on understanding what the universe is made of, its structure and how it is changing with time.

"I use observations of bright objects in optical and radio light to understand the extreme energy processes in the universe," she said.

“I’m delighted to be part of this program and this group of amazing scholars. I am so excited for the enriching partnerships, collaborations and challenges the Global Scholars program will bring to my research practice.”

Julien, who received his PhD at �山ǿ�� in 2010, is the Canada Research Chair in Structural Immunology. He researches how the immune system works, with a focus on antibody-producing B cells.

His research "uses a combination of structural and biophysical techniques to characterize how antibodies are made by the immune system, and how they carry out their function of recognizing foreign molecules," he said.

Meaghan MacSween

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

Fast radio bursts used as 'searchlights' to detect gas in Milky Way

�山ǿ�� undergrad develops AI tool to accelerate the search for alien life

Read more in the Globe and Mail

Researchers study Milky Way's 'feeding habits' in search of clues about its origins

�山ǿ�� astronomer's research suggests 'magnetic tunnel' surrounds our solar system

�山ǿ�� astronomy course gazes at the stars through an Indigenous lens

CHIME study involving �山ǿ�� astronomers finds fast radio bursts repeat 'on the time scale of weeks'

Two �山ǿ�� researchers named CIFAR Azrieli Global Scholars