Astronomers discover record haul of 25 new repeating 'fast radio bursts'

Apr 26 2023

Astronomers have doubled the known number of repeating rapid bursts of powerful radiation emanating from distant galaxies outside the Milky Way.

These blasts, known as fast radio bursts (FRBs), are so powerful they can outshine the entire galaxy from which they emerge. But despite this incredible power, the origins of FRBs are mysterious.

In a new study, a team led by astronomers from the Canadian Hydrogen Intensity Mapping Experiment (CHIME)/FRB Collaboration and the University of Toronto found 25 new repeating FRBs, bringing the total known to 50. This could lead scientists to the discovery of what causes these bursts and also suggests that many more FRBs could eventually repeat than previously thought, team members said.

Astronomers have discovered many FRBs over the last decade, but the vast majority of these have been non-repeating and were only seen to "burst" once. Only a small fraction have been seen to repeat. This has led astronomers to question if repeating FRBs and non-repeating FRBs come from the same sources.

The fact that these two populations of FRBs seem to have different characteristics — including how long they last and the range of frequencies they are seen across — also points to their varied origins. Key to confirming this is the discovery of more repeating FRBs, which the team involved in this research did by developing a new set of statistical tools and combing through data to analyze every repeating FRB ever seen, including ones that aren't immediately obvious.

"We can now accurately calculate the probability that two or more bursts coming from similar locations are not just a coincidence," study team member Ziggy Pleunis, a postdoctoral fellow at the University of Toronto's Dunlap Institute for Astronomy and Astrophysics, said in a statement(opens in new tab). "These new tools were essential for this study, and will also be very useful for similar research going forward."

Radio telescopes like CHIME, which is located at the Dominion Radio Astrophysical Observatory, near Penticton, Canada, have been integral to the detection of FRBs. In the past few years, observations have gone from tens to thousands, and much of this is thanks to CHIME's ability 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 said.

One surprising aspect of this new research is the discovery that many repeating FRBs are surprisingly inactive, producing under one burst per week during CHIME's observing time. Pleunis believes that this could be because these FRBS haven't yet been observed long enough for a second burst to be spotted.

Repeating FRBs are extremely useful to astronomers as they present the opportunity to observe the same FRB source with telescopes other than the one that initially sighted them, allowing these mysterious events to be viewed in finer detail.

"It is exciting that CHIME/FRB saw multiple flashes from the same locations, as this allows for the detailed investigation of their nature," study team member Adaeze Ibik, a University of Toronto Ph.D. student, said in the same statement. "We were able to hone in on some of these repeating sources and have already identified likely associated galaxies for two of them."

The team's findings could also have implications beyond helping narrow down the hunt for the origins of FRBs.

"FRBs are likely produced by the leftovers from explosive stellar deaths. By studying repeating FRB sources in detail, we can study the environments that these explosions occur in and understand better the end stages of a star's life," Pleunis said. "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 new study was published online today (April 26) in The Astrophysical Journal

https://www.space.com/astronomers-find-25-repeating-fast-radio-bursts

https://iopscience.iop.org/article/10.3847/1538-4357/acc6c1

First direct image of a black hole expelling a powerful jet

Apr 26 2023

Most galaxies harbour a supermassive black hole at their centre. While black holes are known for engulfing matter in their immediate vicinity, they can also launch powerful jets of matter that extend beyond the galaxies that they live in. Understanding how black holes create such enormous jets has been a long standing problem in astronomy. “We know that jets are ejected from the region surrounding black holes,” says Ru-Sen Lu from the Shanghai Astronomical Observatory in China, “but we still do not fully understand how this actually happens. To study this directly we need to observe the origin of the jet as close as possible to the black hole.”

The new image published today shows precisely this for the first time: how the base of a jet connects with the matter swirling around a supermassive black hole. The target is the galaxy M87, located 55 million light-years away in our cosmic neighbourhood, and home to a black hole 6.5 billion times more massive than the Sun. Previous observations had managed to separately image the region close to the black hole and the jet, but this is the first time both features have been observed together. “This new image completes the picture by showing the region around the black hole and the jet at the same time,” adds Jae-Young Kim from the Kyungpook National University in South Korea and the Max Planck Institute for Radio Astronomy in Germany.

The image was obtained with the GMVA, ALMA and the GLT, forming a network of radio-telescopes around the globe working together as a virtual Earth-sized telescope. Such a large network can discern very small details in the region around M87’s black hole.

The new image shows the jet emerging near the black hole, as well as what scientists call the shadow of the black hole. As matter orbits the black hole, it heats up and emits light. The black hole bends and captures some of this light, creating a ring-like structure around the black hole as seen from Earth. The darkness at the centre of the ring is the black hole shadow, which was first imaged by the Event Horizon Telescope (EHT) in 2017. Both this new image and the EHT one combine data taken with several radio-telescopes worldwide, but the image released today shows radio light emitted at a longer wavelength than the EHT one: 3.5 mm instead of 1.3 mm. “At this wavelength, we can see how the jet emerges from the ring of emission around the central supermassive black hole,” says Thomas Krichbaum of the Max Planck Institute for Radio Astronomy.

The size of the ring observed by the GMVA network is roughly 50% larger in comparison to the Event Horizon Telescope image. "To understand the physical origin of the bigger and thicker ring, we had to use computer simulations to test different scenarios,” explains Keiichi Asada from the Academia Sinica in Taiwan. The results suggest the new image reveals more of the material that is falling towards the black hole than what could be observed with the EHT.

These new observations of M87’s black hole were conducted in 2018 with the GMVA, which consists of 14 radio-telescopes in Europe and North America [1]. In addition, two other facilities were linked to the GMVA: the Greenland Telescope and ALMA, of which ESO is a partner. ALMA consists of 66 antennas in the Chilean Atacama desert, and it played a key role in these observations. The data collected by all these telescopes worldwide are combined using a technique called interferometry, which synchronises the signals taken by each individual facility. But to properly capture the actual shape of an astronomical object it’s important that the telescopes are spread all over the Earth. The GMVA telescopes are mostly aligned East-to-West, so the addition of ALMA in the Southern hemisphere proved essential to capture this image of the jet and shadow of M87’s black hole. “Thanks to ALMA’s location and sensitivity, we could reveal the black hole shadow and see deeper into the emission of the jet at the same time,” explains Lu.

Future observations with this network of telescopes will continue to unravel how supermassive black holes can launch powerful jets. “We plan to observe the region around the black hole at the centre of M87 at different radio wavelengths to further study the emission of the jet,” says Eduardo Ros from the Max Planck Institute for Radio Astronomy. Such simultaneous observations would allow the team to disentangle the complicated processes that happen near the supermassive black hole. “The coming years will be exciting, as we will be able to learn more about what happens near one of the most mysterious regions in the Universe,” concludes Ros.

https://www.space.com/black-hole-jet-first-direct-image-m87

https://www.eso.org/public/news/eso2305/

VP Harris, South Korea President Yoon Visit NASA Goddard

Apr 25, 2023

Vice President Kamala Harris and Republic of Korea (ROK) President Yoon Suk Yeol saw firsthand Tuesday how NASA studies climate change during a visit to NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

“The climate crisis poses an existential threat to our world,” Harris said. “And to meet this threat, we must partner together to use satellite technology to monitor the impacts of that crisis on Earth. As one example, together our nations have built and placed satellites in orbit that can track air pollution in North America and Asia.”

Those missions are NASA’s recently launched Tropospheric Emissions: Monitoring of Pollution (TEMPO) mission and the ROK’s Geostationary Environment Monitoring Spectrometer (GEMS) mission. Both are improving life on Earth by revolutionizing the way scientists observe air quality from space.

“The United States and the Republic of Korea have a long-standing partnership across our shared interests — including science and technology at the Moon, Earth science, aeronautics research, and more,” said NASA Deputy Administrator Pam Melroy. “Our growing cooperation is proving that the future of space is collaborative and will strengthen our scientific discovery in space and on Earth for decades to come.”

Melroy and Goddard Center Director Makenzie Lystrup joined Harris and Yoon on the tour, which included a meeting with Korean-American scientists and a briefing on the importance of space to addressing climate change.

During their visit, Harris and Yoon also saw NASA’s Nancy Grace Roman Space Telescope, currently under construction at Goddard. The telescope is designed to unravel the secrets of dark energy and dark matter, search for and image exoplanets, and explore many topics in infrared astrophysics.

“We were honored to demonstrate today how Goddard continues to make groundbreaking discoveries in Earth and space science, as well as how our other work supports NASA’s mission for the benefit of humanity,” Lystrup said.

Melroy and Korean Minister of Science and ICT Lee Jong-ho signed a joint statement of intent between the U.S. and ROK that promises to further cooperation in science and exploration.

Harris previously visited Goddard in 2021 to discuss with scientists and engineers the agency’s range of Earth science missions that help address climate challenges.

https://www.nasa.gov/feature/goddard/2023/vp-harris-south-korea-president-yoon-visit-nasa-goddard

https://www.flickr.com/photos/nasahqphoto/sets/72177720307785742/

Asteroid’s Comet-Like Tail Is Not Made of Dust, Solar Observatories Reveal

Apr 25, 2023

A weird asteroid has just gotten a little weirder.

We have known for a while that asteroid 3200 Phaethon acts like a comet. It brightens and forms a tail when it’s near the Sun, and it is the source of the annual Geminid meteor shower, even though comets are responsible for most meteor showers. Scientists had blamed Phaethon’s comet-like behavior on dust escaping from the asteroid as it’s scorched by the Sun. However, a new study using two NASA solar observatories reveals that Phaethon’s tail is not dusty at all but is actually made of sodium gas.

“Our analysis shows that Phaethon’s comet-like activity cannot be explained by any kind of dust,” said California Institute of Technology PhD student Qicheng Zhang, who is the lead author of a paper published in the Planetary Science Journal reporting the results.

Asteroids, which are mostly rocky, do not usually form tails when they approach the Sun. Comets, however, are a mix of ice and rock, and typically do form tails as the Sun vaporizes their ice, blasting material off their surfaces and leaving a trail along their orbits. When Earth passes through a debris trail, those cometary bits burn up in our atmosphere and produce a swarm of shooting stars – a meteor shower.

After astronomers discovered Phaethon in 1983, they realized that the asteroid’s orbit matched that of the Geminid meteors. This pointed to Phaethon as the source of the annual meteor shower, even though Phaethon was an asteroid and not a comet.

In 2009, NASA’s Solar Terrestrial Relations Observatory (STEREO) spotted a short tail extending from Phaethon as the asteroid reached its closest point to the Sun (or “perihelion”) along its 524-day orbit. Regular telescopes hadn’t seen the tail before because it only forms when Phaethon is too close to the Sun to observe, except with solar observatories. STEREO also saw Phaethon’s tail develop on later solar approaches in 2012 and 2016. The tail’s appearance supported the idea that dust was escaping the asteroid’s surface when heated by the Sun.

However, in 2018, another solar mission imaged part of the Geminid debris trail and found a surprise. Observations from NASA’s Parker Solar Probe showed that the trail contained far more material than Phaethon could possibly shed during its close approaches to the Sun.

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Zhang’s team wondered whether something else, other than dust, was behind Phaethon’s comet-like behavior. “Comets often glow brilliantly by sodium emission when very near the Sun, so we suspected sodium could likewise serve a key role in Phaethon’s brightening,” Zhang said.

An earlier study, based on models and lab tests, suggested that the Sun’s intense heat during Phaethon’s close solar approaches could indeed vaporize sodium within the asteroid and drive comet-like activity.

Hoping to find out what the tail is really made of, Zhang looked for it again during Phaethon’s latest perihelion in 2022. He used the Solar and Heliospheric Observatory (SOHO) spacecraft — a joint mission between NASA and the European Space Agency (ESA) – which has color filters that can detect sodium and dust. Zhang’s team also searched archival images from STEREO and SOHO, finding the tail during 18 of Phaethon’s close solar approaches between 1997 and 2022.

In SOHO’s observations, the asteroid’s tail appeared bright in the filter that detects sodium, but it did not appear in the filter that detects dust. In addition, the shape of the tail and the way it brightened as Phaethon passed the Sun matched exactly what scientists would expect if it were made of sodium, but not if it were made of dust.

This evidence indicates that Phaethon’s tail is made of sodium, not dust.

“Not only do we have a really cool result that kind of upends 14 years of thinking about a well-scrutinized object,” said team member Karl Battams of the Naval Research Laboratory, “but we also did this using data from two heliophysics spacecraft – SOHO and STEREO – that were not at all intended to study phenomena like this.”

Zhang and his colleagues now wonder whether some comets discovered by SOHO – and by citizen scientists studying SOHO images as part of the Sungrazer Project – are not comets at all.

“A lot of those other sunskirting ‘comets’ may also not be ‘comets’ in the usual, icy body sense, but may instead be rocky asteroids like Phaethon heated up by the Sun,” Zhang explained.

Still, one important question remains: If Phaethon doesn’t shed much dust, how does the asteroid supply the material for the Geminid meteor shower we see each December?

Zhang’s team suspects that some sort of disruptive event a few thousand years ago – perhaps a piece of the asteroid breaking apart under the stresses of Phaethon’s rotation – caused Phaethon to eject the billion tons of material estimated to make up the Geminid debris stream. But what that event was remains a mystery.

More answers may come from an upcoming Japan Aerospace Exploration Agency (JAXA) mission called DESTINY+ (short for Demonstration and Experiment of Space Technology for Interplanetary voyage Phaethon fLyby and dUst Science). Later this decade, the DESTINY+ spacecraft is expected to fly past Phaethon, imaging its rocky surface and studying any dust that might exist around this enigmatic asteroid.

https://www.nasa.gov/feature/goddard/2023/sun/asteroid-s-comet-like-tail-is-not-made-of-dust-solar-observatories-reveal

https://iopscience.iop.org/article/10.3847/PSJ/acc866

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NASA Sets Coverage for Czech Republic Artemis Accords Signing Ceremony

Apr 26, 2023

The Czech Republic is expected to sign the Artemis Accords during a ceremony at NASA Headquarters in Washington Wednesday, May 3.

The agency will provide live coverage of the signing ceremony starting 10 a.m. EDT on NASA Television, the NASA app, and on the agency’s website at: https://www.nasa.gov/live

NASA Administrator Bill Nelson will participate in the signing ceremony for the agency and Foreign Minister Jan Lipavský will sign on behalf of the Czech Republic. Acting Assistant Secretary Jennifer R. Littlejohn and Czech Ambassador to the United States Miloslav Stašek will also take part in the ceremony.

The Artemis Accords establish a practical set of principles to guide space exploration cooperation among nations, including those participating in NASA’s Artemis program.

NASA, in coordination with the U.S. Department of State, announced the establishment of the Artemis Accords in 2020 along with the original signatories. The Artemis Accords reinforce and implement the 1967 Outer Space Treaty. They also reinforce the commitment by the United States and partner nations to the Registration Convention, the Rescue and Return Agreement, as well as best practices and norms of responsible behavior that NASA and its partners have supported, including the public release of scientific data.

https://www.nasa.gov/press-release/nasa-sets-coverage-for-czech-republic-artemis-accords-signing-ceremony

https://www.nasa.gov/specials/artemis-accords/index.html

>>18758117

Dude is laying pipe everywhere

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