Radio signal reveals supernova origin

In the latest issue of the journal Nature, astronomers from Stockholm University reveal the origin of a thermonuclear supernova explosion. Strong emission lines of helium and the first detection of such a supernova in radio waves show that the exploding white dwarf star had a helium-rich companion.

Supernovae of Type Ia are important for astronomers since they are used to measure the expansion of the Universe. However, the origin of these explosions has remained an open question. While it is established that the explosion is that of a compact white dwarf star somehow accreting too much matter from a companion star, the exact process and the nature of the progenitor is not known. The new discovery of supernova SN 2020eyj established that the companion star was a helium star that had lost much of its material just prior to the explosion of the white dwarf.

"Once we saw the signatures of strong interaction with the material from the companion we tried to also detect it in radio emission," explains Erik Kool, post-doc at the Department of Astronomy at Stockholm university and lead author of the paper. "The detection in radio is the first one of a Type Ia supernova -- something astronomers have tried to do for decades."

Supernova 2020eyj was discovered by the Zwicky Transient Facility camera on Palomar mountain, where the Oskar Klein Centre at Stockholm University are members.

"The Nordic Optical telescope on La Palma was fundamental for following up this supernova," says Professor Jesper Sollerman at the Department of Astronomy and co-author of the paper. "As were spectra from the large Keck telescope on Hawai'i that immediately revealed the very unusual helium-dominated material around the exploded star."

"This is clearly a very unusual Type Ia supernova, but still related to the ones we use to measure the expansion of the universe," adds Joel Johansson from the Department of Physics.

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Characterizing the earliest galaxies in the universe -- only 200 million years after the Big Bang

An international team of astrophysicists, including Prof. Rennan Barkana from the Sackler School of Physics and Astronomy at Tel Aviv University, has managed for the first time to statistically characterize the first galaxies in the Universe, which formed only 200 million years after the Big Bang. According to the groundbreaking results, the earliest galaxies were relatively small and dim. They were fainter than present-day galaxies, and likely processed only 5% or less of their gas into stars. Furthermore, the first galaxies did not emit radio waves at an intensity that was much higher than that of modern galaxies.

This new study, carried out together with the SARAS observation team, was led by the research group of Dr. Anastasia Fialkov from the University of Cambridge, England, a former PhD student of Prof. Barkana. The results of this innovative study were published in the journal Nature Astronomy.

"This is a very new field and a first-of-its-kind study," explains Prof. Barkana. "We are trying to understand the epoch of the first stars in the Universe, known as the 'cosmic dawn', about 200 million years after the Big Bang. The James Webb Space Telescope, for example, can't really see these stars. It might only detect a few particularly bright galaxies from a somewhat later period. Our goal is to probe the entire population of the first stars."

According to the standard picture, before stars began to fuse heavier elements inside their cores, our Universe was nothing but a cloud of hydrogen atoms from the Big Bang (other than some helium and a lot of dark matter). Today the Universe is also filled with hydrogen, but in the modern Universe it is mostly ionized due to radiation from stars.

"Hydrogen atoms naturally emit light at a wavelength of 21cm, which falls within the spectrum of radio waves," says Prof. Barkana. "Since stellar radiation affects the light emitted by hydrogen atoms, we use hydrogen as a detector in our search for the first stars: if we can detect the effect of stars on hydrogen, we will know when they were born, and in what types of galaxies. I was among the first theorists to develop this concept 20 years ago, and now observers are able to implement it in actual experiments. Teams of experimentalists all over the world are currently attempting to discover the 21cm signal from hydrogen in the early Universe."

One of these teams is EDGES, which uses a fairly small radio antenna that measures the average intensity on the entire sky of radio waves arriving from different periods of the cosmic dawn. In 2018, the EDGES team announced that it had found the 21cm signal from ancient hydrogen.

"There was a problem with their findings, however," says Prof. Barkana. "We could not be sure that the measured signal did indeed come from hydrogen in the early Universe. It could have been a fake signal produced by the electrical conductivity of the ground below the antenna. Therefore, we all waited for an independent measurement that would either confirm or refute these results. Last year astronomers in India carried out an experiment called SARAS, in which the antenna was made to float on a lake, a uniform surface of water that could not mimic the desired signal. According to the results of the new experiment, there was a 95% probability that EDGES did not in fact detect a real signal from the early Universe. SARAS found an upper limit for the genuine signal, implying that the signal from early hydrogen is likely significantly weaker than the one measured by EDGES. We modeled the SARAS result and worked out the implications for the first galaxies, i.e., what their properties were given the upper limit determined by SARAS. Now we can say for the first time that galaxies of certain types could not have existed at that early time."

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Astronomers detect 'galactic space laser'

A powerful radio-wave laser, called a 'megamaser', has been observed by the MeerKAT telescope in South Africa.

The record-breaking find is the most distant megamaser of its kind ever detected, at about five billion light years from Earth.

The light from the megamaser has travelled 58 thousand billion billion (58 followed by 21 zeros) kilometres to Earth.

The discovery was made by an international team of astronomers led by Dr Marcin Glowacki, who previously worked at the Inter-University Institute for Data Intensive Astronomy and the University of the Western Cape in South Africa.

Dr Glowacki, who is now based at the Curtin University node of the International Centre for Radio Astronomy Research (ICRAR) in Western Australia, said megamasers are usually created when two galaxies violently collide in the Universe.

"When galaxies collide, the gas they contain becomes extremely dense and can trigger concentrated beams of light to shoot out," he said.

"This is the first hydroxyl megamaser of its kind to be observed by MeerKAT and the most distant seen by any telescope to date.

"It's impressive that, with just a single night of observations, we've already found a record-breaking megamaser. It shows just how good the telescope is."

The record-breaking object was named 'Nkalakatha' [pronounced ng-kuh-la-kuh-tah] -- an isiZulu word meaning "big boss."

Dr Glowacki said the megamaser was detected on the first night of a survey involving more than 3000 hours of observations by the MeerKAT telescope.

The team is using MeerKAT to observe narrow regions of the sky extremely deeply and will measure atomic hydrogenin galaxies from the distant past to now. The combination of studying hydroxl masers and hydrogen will help astronomers better understand how the Universe has evolved over time.

"We have follow-up observations of the megamaser planned and hope to make many more discoveries," Dr Glowacki said.

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Mysterious object unlike anything astronomers have seen before

A team mapping radio waves in the Universe has discovered something unusual that releases a giant burst of energy three times an hour, and it's unlike anything astronomers have seen before.

The team who discovered it think it could be a neutron star or a white dwarf -- collapsed cores of stars -- with an ultra-powerful magnetic field.

Spinning around in space, the strange object sends out a beam of radiation that crosses our line of sight, and for a minute in every twenty, is one of the brightest radio sources in the sky.

Astrophysicist Dr Natasha Hurley-Walker, from the Curtin University node of the International Centre for Radio Astronomy Research, led the team that made the discovery.

"This object was appearing and disappearing over a few hours during our observations," she said.

"That was completely unexpected. It was kind of spooky for an astronomer because there's nothing known in the sky that does that.

"And it's really quite close to us -- about 4000 lightyears away. It's in our galactic backyard."

The object was discovered by Curtin University Honours student Tyrone O'Doherty using the Murchison Widefield Array (MWA) telescope in outback Western Australia and a new technique he developed.

"It's exciting that the source I identified last year has turned out to be such a peculiar object," said Mr O'Doherty, who is now studying for a PhD at Curtin.

"The MWA's wide field of view and extreme sensitivity are perfect for surveying the entire sky and detecting the unexpected."

Objects that turn on and off in the Universe aren't new to astronomers -- they call them 'transients'.

ICRAR-Curtin astrophysicist and co-author Dr Gemma Anderson said that "when studying transients, you're watching the death of a massive star or the activity of the remnants it leaves behind."

'Slow transients' -- like supernovae -- might appear over the course of a few days and disappear after a few months.

'Fast transients' -- like a type of neutron star called a pulsar -- flash on and off within milliseconds or seconds.

But Dr Anderson said finding something that turned on for a minute was really weird.

She said the mysterious object was incredibly bright and smaller than the Sun, emitting highly-polarised radio waves -- suggesting the object had an extremely strong magnetic field.

Dr Hurley-Walker said the observations match a predicted astrophysical object called an 'ultra-long period magnetar'.

"It's a type of slowly spinning neutron star that has been predicted to exist theoretically," she said.

"But nobody expected to directly detect one like this because we didn't expect them to be so bright.

"Somehow it's converting magnetic energy to radio waves much more effectively than anything we've seen before."

Dr Hurley-Walker is now monitoring the object with the MWA to see if it switches back on.

"If it does, there are telescopes across the Southern Hemisphere and even in orbit that can point straight to it," she said.

Dr Hurley-Walker plans to search for more of these unusual objects in the vast archives of the MWA.

"More detections will tell astronomers whether this was a rare one-off event or a vast new population we'd never noticed before," she said.

MWA Director Professor Steven Tingay said the telescope is a precursor instrument for the Square Kilometre Array -- a global initiative to build the world's largest radio telescopes in Western Australia and South Africa.

"Key to finding this object, and studying its detailed properties, is the fact that we have been able to collect and store all the data the MWA produces for almost the last decade at the Pawsey Research Supercomputing Centre. Being able to look back through such a massive dataset when you find an object is pretty unique in astronomy," he said.

"There are, no doubt, many more gems to be discovered by the MWA and the SKA in coming years."

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Seeing with radio waves

Scientists from the Division of Physics at the University of Tsukuba used the quantum effect called "spin-locking" to significantly enhance the resolution when performing radio-frequency imaging of nitrogen-vacancy defects in diamond. This work may lead to faster and more accurate material analysis, as well as a path towards practical quantum computers.

Nitrogen-vacancy (NV) centers have long been studied for their potential use in quantum computers. A NV center is a type of defect in the lattice of a diamond, in which two adjacent carbon atoms have been replaced with a nitrogen atom and a void. This leaves an unpaired electron, which can be detected using radio-frequency waves, because its probability of emitting a photon depends on its spin state. However, the spatial resolution of radio wave detection using conventional radio-frequency techniques has remained less than optimal.

Now, researchers at the University of Tsukuba have pushed the resolution to its limit by employing a technique called "spin-locking." Microwave pulses are used to put the electron's spin in a quantum superposition of up and down simultaneously. Then, a driving electromagnetic field causes the direction of the spin to precess around, like a wobbling top. The end result is an electron spin that is shielded from random noise but strongly coupled to the detection equipment. "Spin-locking ensures high accuracy and sensitivity of the electromagnetic field imaging," first author Professor Shintaro Nomura explains. Due to the high density of NV centers in the diamond samples used, the collective signal they produced could be easily picked up with this method. This permitted the sensing of collections of NV centers at the micrometer scale. "The spatial resolution we obtained with RF imaging was much better than with similar existing methods," Professor Nomura continues, "and it was limited only by the resolution of the optical microscope we used."

The approach demonstrated in this project may be applied in a broad variety of application areas -- for example, the characterizations of polar molecules, polymers, and proteins, as well as the characterization of materials. It might also be used in medical applications -- for example, as a new way to perform magnetocardiography.

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Fast radio bursts shown to include lower frequency radio waves than previously detected

Since fast radio bursts (FRBs) were first discovered over a decade ago, scientists have puzzled over what could be generating these intense flashes of radio waves from outside of our galaxy. In a gradual process of elimination, the field of possible explanations has narrowed as new pieces of information are gathered about FRBs -- how long they last, the frequencies of the radio waves detected, and so on.

Now, a team led by McGill University researchers and members of Canada's CHIME Fast Radio Burst collaboration has established that FRBs include radio waves at frequencies lower than ever detected before, a discovery that redraws the boundaries for theoretical astrophysicists trying to put their finger on the source of FRBs.

"We detected fast radio bursts down to 110 MHz where before these bursts were only known to exist down to 300 MHz," explained Ziggy Pleunis, a postdoctoral researcher in McGill's Department of Physics and lead author of the research recently published in the Astrophysical Journal Letters. "This tells us that the region around the source of the bursts must be transparent to low-frequency emission, whereas some theories suggested that all low-frequency emission would be absorbed right away and could never be detected."

The study focussed on an FRB source first detected in 2018 by the CHIME radio telescope in British Columbia. Known as FRB 20180916B, the source has attracted particular attention because of its relative proximity to Earth and the fact that it emits FRBs at regular intervals.

The research team combined the capacities of CHIME with those of another radio telescope, LOFAR, or Low Frequency Array, in the Netherlands. The joint effort not only enabled the detection of the remarkably low FRB frequencies, but also revealed a consistent delay of around three days between the higher frequencies being picked up by CHIME and the lower ones reaching LOFAR.

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How colliding neutron stars could shed light on universal mysteries

An important breakthrough in how we can understand dead star collisions and the expansion of the Universe has been made by an international team, led by the University of East Anglia.

They have discovered an unusual pulsar -- one of deep space's magnetized spinning neutron-star 'lighthouses' that emits highly focused radio waves from its magnetic poles.

The newly discovered pulsar (known as PSR J1913+1102) is part of a binary system -- which means that it is locked in a fiercely tight orbit with another neutron star.

Neutron stars are the dead stellar remnants of a supernova. They are made up of the most dense matter known -- packing hundreds of thousands of times the Earth's mass into a sphere the size of a city.

In around half a billion years the two neutron stars will collide, releasing astonishing amounts of energy in the form of gravitational waves and light.

But the newly discovered pulsar is unusual because the masses of its two neutron stars are quite different -- with one far larger than the other.

This asymmetric system gives scientists confidence that double neutron star mergers will provide vital clues about unsolved mysteries in astrophysics -- including a more accurate determination of the expansion rate of the Universe, known as the Hubble constant.

The discovery, published today in the journal Nature, was made using the Arecibo radio telescope in Puerto Rico.

Lead researcher Dr Robert Ferdman, from UEA's School of Physics, said: "Back in 2017, scientists at the Laser Interferometer Gravitational-Wave Observatory (LIGO) first detected the merger of two neutron stars.

"The event caused gravitational-wave ripples through the fabric of space time, as predicted by Albert Einstein over a century ago."

Known as GW170817, this spectacular event was also seen with traditional telescopes at observatories around the world, which identified its location in a distant galaxy, 130 million light years from our own Milky Way.

Dr Ferdman said: "It confirmed that the phenomenon of short gamma-ray bursts was due to the merger of two neutron stars. And these are now thought to be the factories that produce most of the heaviest elements in the Universe, such as gold."

The power released during the fraction of a second when two neutron stars merge is enormous -- estimated to be tens of times larger than all stars in the Universe combined.

So the GW170817 event was not surprising. But the enormous amount of matter ejected from the merger and its brightness was an unexpected mystery.

Dr Ferdman said: "Most theories about this event assumed that neutron stars locked in binary systems are very similar in mass.

"Our new discovery changes these assumptions. We have uncovered a binary system containing two neutron stars with very different masses.

"These stars will collide and merge in around 470 million years, which seems like a long time, but it is only a small fraction of the age of the Universe.

"Because one neutron star is significantly larger, its gravitational influence will distort the shape of its companion star -- stripping away large amounts of matter just before they actually merge, and potentially disrupting it altogether.

"This 'tidal disruption' ejects a larger amount of hot material than expected for equal-mass binary systems, resulting in a more powerful emission.

"Although GW170817 can be explained by other theories, we can confirm that a parent system of neutron stars with significantly different masses, similar to the PSR J1913+1102 system, is a very plausible explanation.

"Perhaps more importantly, the discovery highlights that there are many more of these systems out there -- making up more than one in 10 merging double neutron star binaries."

Co-author Dr Paulo Freire from the Max Planck Institute for Radio Astronomy in Bonn, Germany, said: "Such a disruption would allow astrophysicists to gain important new clues about the exotic matter that makes up the interiors of these extreme, dense objects.

"This matter is still a major mystery -- it's so dense that scientists still don't know what it is actually made of. These densities are far beyond what we can reproduce in Earth-based laboratories."

The disruption of the lighter neutron star would also enhance the brightness of the material ejected by the merger. This means that along with gravitational-wave detectors such as the US-based LIGO and the Europe-based Virgo detector, scientists will also be able to observe them with conventional telescopes.

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A fast radio burst tracked down to a nearby galaxy

Gemini telescopes, Mauna Kea, Hawaii.

Astronomers in Europe, working with members of Canada's CHIME Fast Radio Burst collaboration, have pinpointed the location of a repeating fast radio burst (FRB) first detected by the CHIME telescope in British Columbia in 2018. The breakthrough is only the second time that scientists have determined the precise location of a repeating source of these millisecond bursts of radio waves from space.

In results published in the January 9 edition of Nature, the European VLBI Network (EVN) used eight telescopes spanning locations from the United Kingdom to China to simultaneously observe the repeating radio source known as FRB 180916.J0158+65. Using a technique known as Very Long Baseline Interferometry (VLBI), the researchers achieved a level of resolution high enough to localize the FRB to a region approximately seven light years across -- a feat comparable to an individual on Earth being able to distinguish a person on the Moon.

A 'very different' location for an FRB

With that level of precision, the research team was able to train an optical telescope onto the location to learn more about the environment from which the burst emanated. What they found has added a new chapter to the mystery surrounding the origins of FRBs.

"We used the eight-metre Gemini North telescope in Hawaii to take sensitive images that showed the faint spiral arms of a Milky-Way-like galaxy and showed that the FRB source was in a star-forming region in one of those arms," said co-author Shriharsh Tendulkar, a former McGill University postdoctoral researcher who co-led the optical imaging and spectroscopic analyses of the FRB's location.

"This is a very different environment for a repeating FRB, compared to the dwarf galaxy in which the first repeating FRB 121102 was discovered to reside."

CHIME team's hypotheses in line with observed data

The discovery lined up with a number of ideas CHIME/FRB researchers had put forward following their initial detection of the burst in 2018.

"The FRB is among the closest yet seen and we even speculated that it could be a more conventional object in the outskirts of our own galaxy," said co-author Mohit Bhardwaj, a McGill University doctoral student and CHIME team member.

"However the EVN observation proved that it's in a relatively nearby galaxy, making it still a puzzling FRB, but close enough to now study using many other telescopes."

Zooming in on the radio sky

Since it began operation in the summer of 2018, CHIME has detected dozens of fast radio bursts, greatly accelerating the rate of discovery of these transient astrophysical phenomena. With over 1,000 antennas, CHIME's large field of view gives it a much greater chance of picking up fleeting bursts than conventional radio telescopes that are able to observe only a small area of the sky at a time.

When it came to pinpointing FRB 180916, the CHIME/FRB team worked closely with their EVN colleagues to determine exactly where to point the VLBI telescopes.

"By recording and processing the raw signal from each of the antenna elements that make up CHIME, we were able to refine the source position to a level close enough for EVN to successfully observe and localize multiple bursts from this FRB source," said co-author Daniele Michilli, a McGill University postdoctoral researcher and CHIME/FRB team member.

FRB's proximity opens the way for further study

At half-a-billion light years from Earth, the source of FRB 180916 is around seven times closer than the only other repeating burst to have been localized, and more than 10 times closer than any of the few non-repeating FRBs scientists have managed to pinpoint. That's exciting for astronomers because it will enable more detailed study that may help narrow down the possible explanations for FRBs.

"We have a new chance to perhaps detect emissions at other wavelengths -- x-ray or visible light, for instance," said McGill University astrophysicist Victoria Kaspi, a leading member of the CHIME/FRB collaboration. "And if we did, that would be hugely constraining of the models."

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Astronomers make first detection of polarized radio waves in Gamma Ray Burst jets

Black hole illustration

Good fortune and cutting-edge scientific equipment have allowed scientists to observe a Gamma Ray Burst jet with a radio telescope and detect the polarisation of radio waves within it for the first time -- moving us closer to an understanding of what causes the universe's most powerful explosions.

Gamma Ray Bursts (GRBs) are the most energetic explosions in the universe, beaming out mighty jets which travel through space at over 99.9% the speed of light, as a star much more massive than our sun collapses at the end of its life to produce a black hole.

Studying the light from Gamma Ray Burst jets as we detect it travelling across space is our best hope of understanding how these powerful jets are formed, but scientists need to be quick to get their telescopes into position and get the best data. The detection of polarised radio waves from a burst's jet, made possible by a new generation of advanced radio telescopes, offers new clues to this mystery.

The light from this particular event, known as GRB 190114C, which exploded with the force of millions of suns' worth of TNT about 4.5 billion years ago, reached NASA's Neil Gehrels Swift Observatory on Jan 14, 2019.

A rapid alert from Swift allowed the research team to direct the Atacama Large Millimeter/Sub-millimeter Array (ALMA) telescope in Chile to observe the burst just two hours after Swift discovered it. Two hours later the team was able to observe the GRB from the Karl G. Jansky Very Large Array (VLA) telescope when it became visible in New Mexico, USA.

Combining the measurements from these observatories allowed the research team to determine the structure of magnetic fields within the jet itself, which affects how the radio light is polarised. Theories predict different arrangements of magnetic fields within the jet depending on the fields' origin, so capturing radio data enabled the researchers to test these theories with observations from telescopes for the first time.

The research team, from the University of Bath, Northwestern University, the Open University of Israel, Harvard University, California State University in Sacramento, the Max Planck Institute in Garching, and Liverpool John Moores University discovered that only 0.8% of the jet light was polarised, meaning that jet's magnetic field was only ordered over relatively small patches -- each less than about 1% of the diameter of the jet. Larger patches would have produced more polarised light.

These measurements suggest that magnetic fields may play a less significant structural role in GRB jets than previously thought.

This helps us narrow down the possible explanations for what causes and powers these extraordinary explosions. The study is published in Astrophysical Journal Letters.

First author Dr Tanmoy Laskar, from the University of Bath's Astrophysics group, said: "We want to understand why some stars produce these extraordinary jets when they die, and the mechanism by which these jets are fuelled -- the fastest known outflows in the universe, moving at speeds close to that of light and shining with the incredible luminosity of over a billion suns combined.

"I was in a cab on my way to O'Hare airport in Chicago, following a visit with collaborators when the burst went off. The extreme brightness of this event and the fact that it was visible in Chile right away made it a prime target for our study, and so I immediately contacted ALMA to say we were going to observe this one, in the hope of detecting the first radio polarisation signal.

"It was fortuitous that the target was well placed in the sky for observations with both ALMA in Chile and the VLA in New Mexico. Both facilities responded quickly and the weather was excellent. We then spent two months in a painstaking process to make sure our measurement was genuine and free from instrumental effects. Everything checked out, and that was exciting.

Dr Kate Alexander, who led the VLA observations, said: "The lower frequency data from the VLA helped confirm that we were seeing the light from the jet itself, rather than from the interaction of the jet with its environment."

Dr Laskar added: "This measurement opens a new window into GRB science and the studies of energetic astrophysical jets. We would like to understand whether the low level of polarisation measured in this event is characteristic of all GRBs, and if so, what this could tell us about the magnetic structures in GRB jets and the role of magnetic fields in powering jets throughout the universe."

Professor Carole Mundell, Head of Astrophysics at the University of Bath, added: "The exquisite sensitivity of ALMA and rapid response of the telescopes has, for the first time, allowed us to swiftly and accurately measure the degree of polarisation of microwaves from a GRB afterglow just two hours after the blast and probe the magnetic fields that are thought to drive these powerful, ultrafast outflows."

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New telescope almost doubles known number of mysterious 'fast radio bursts'

These are antennas of CSIRO's Australian SKA Pathfinder with the Milky Way overhead.

Australian researchers using a CSIRO radio telescope in Western Australia have nearly doubled the known number of 'fast radio bursts' -- powerful flashes of radio waves from deep space.

The team's discoveries include the closest and brightest fast radio bursts ever detected.

Their findings were reported today in the journal Nature.

Fast radio bursts come from all over the sky and last for just milliseconds.

Scientists don't know what causes them but it must involve incredible energy -- equivalent to the amount released by the Sun in 80 years.

"We've found 20 fast radio bursts in a year, almost doubling the number detected worldwide since they were discovered in 2007," said lead author Dr Ryan Shannon, from Swinburne University of Technology and the OzGrav ARC Centre of Excellence.

"Using the new technology of the Australia Square Kilometre Array Pathfinder (ASKAP), we've also proved that fast radio bursts are coming from the other side of the Universe rather than from our own galactic neighbourhood."

Co-author Dr Jean-Pierre Macquart, from the Curtin University node of the International Centre for Radio Astronomy Research (ICRAR), said bursts travel for billions of years and occasionally pass through clouds of gas.

"Each time this happens, the different wavelengths that make up a burst are slowed by different amounts," he said.

"Eventually, the burst reaches Earth with its spread of wavelengths arriving at the telescope at slightly different times, like swimmers at a finish line.

"Timing the arrival of the different wavelengths tells us how much material the burst has travelled through on its journey.

"And because we've shown that fast radio bursts come from far away, we can use them to detect all the missing matter located in the space between galaxies -- which is a really exciting discovery."

CSIRO's Dr Keith Bannister, who engineered the systems that detected the bursts, said ASKAP's phenomenal discovery rate is down to two things.

"The telescope has a whopping field of view of 30 square degrees, 100 times larger than the full Moon," he said.

"And, by using the telescope's dish antennas in a radical way, with each pointing at a different part of the sky, we observed 240 square degrees all at once -- about a thousand times the area of the full Moon.

"ASKAP is astoundingly good for this work."

Dr Shannon said we now know that fast radio bursts originate from about halfway across the Universe but we still don't know what causes them or which galaxies they come from.

The team's next challenge is to pinpoint the locations of bursts on the sky.

"We'll be able to localise the bursts to better than a thousandth of a degree," Dr Shannon said.

"That's about the width of a human hair seen ten metres away, and good enough to tie each burst to a particular galaxy."

ASKAP is located at CSIRO's Murchison Radio-astronomy Observatory (MRO) in Western Australia and is a precursor for the future Square Kilometre Array (SKA) telescope.

The SKA could observe large numbers of fast radio bursts, giving astronomers a way to study the early Universe in detail.

Read more at Science Daily

A repeating fast radio burst from an extreme environment

Arecibo Observatory, Puerto Rico

New detections of radio waves from a repeating fast radio burst have revealed an astonishingly potent magnetic field in the source's environment, indicating that it is situated near a massive black hole or within a nebula of unprecedented power.

The findings by an international team of astronomers, including Victoria Kaspi and Shriharsh Tendulkar of McGill University, appear in the January 11 edition of Nature and are highlighted on the cover of the journal.

A year ago, the astronomers pinpointed the location of the enigmatic fast radio burst (FRB) source named FRB 121102 and reported that it lies in a star-forming region of a dwarf galaxy more than 3 billion light years from Earth. The vast distance to the source implies that it releases an enormous amount of energy in each burst -- roughly as much energy in a single millisecond as the Sun releases in an entire day.

Now, using data from the Arecibo Observatory (Puerto Rico) and the Green Bank Telescope (West Virginia), the researchers have shown that the radio bursts from FRB121102 are highly polarized. The behavior of this polarized emission enables scientists to probe the source's environment in a new way.

Twisted polarization

When polarized radio waves pass through a region with a magnetic field, the polarization gets ``twisted'' by an effect known as Faraday rotation: the stronger the magnetic field, the greater the twisting. The amount of twisting observed in FRB 121102's radio bursts is among the largest ever measured in a radio source, leading the researchers to conclude that the bursts are passing through an extraordinarily strong magnetic field in a dense plasma.

"I could not believe my eyes when my colleagues emailed the results around," says Kaspi, who is a professor of physics at McGill and director of the McGill Space Institute. "This sort of enormous Faraday rotation is extremely rare. Once we digested it, we realized it was a huge clue about where this bizarre source resides."

One possible explanation for the hugely magnetized environment is that FRB 121102 is located close to a massive black hole in its host galaxy. Such highly magnetized plasmas have so far been seen only near the center of the Milky Way, which has its own massive black hole. But the authors also speculate that the twisting of the radio bursts could be explained if FRB 121102 is located in a powerful nebula (an interstellar cloud of gas and dust) or amid the remains of a dead star.

FRBs are a recently discovered class of transient astrophysical events, originating from deep in extragalactic space. Their physical nature remains a mystery. FRB 121102 is the only known repeating FRB, and this has also raised the question of whether it has a different origin compared to the apparently non-repeating FRBs. "FRB 121102 was already unique because of its repetition; now the huge Faraday rotation we have observed singles it out yet again. We're curious as to whether these two unique aspects are linked," says Daniele Michilli, PhD candidate at the University of Amsterdam and ASTRON (Netherlands Institute for Radio Astronomy).

New telescopes could provide answers

With a number of wide-field radio telescopes now coming online, more such sources are expected to be discovered in the coming year, and astronomers are poised to answer more fundamental questions about FRBs.

"The CHIME telescope in Penticton, British Columbia, should be an excellent instrument for detecting fast radio bursts and studying their polarization properties," says Shriharsh Tendulkar, postdoctoral researcher at the McGill Space Institute. "When it comes online in 2018, it should be capable of detecting between a few and a few dozen FRBs every day."

Read more at Science Daily