From WIRED: “An Alien-Hunting Tech Mogul May Help Solve a Space Mystery”

From WIRED

07.21.19
Katia Moskvitch

Yuri Milner. Billy H.C. Kwok/Getty Images

In spring 2007, David Narkevic, a physics student at West Virginia University, was sifting through reams of data churned out by the Parkes telescope—a dish in Australia that had been tracking pulsars, the collapsed, rapidly spinning cores of once massive stars.

CSIRO/Parkes Observatory, located 20 kilometres north of the town of Parkes, New South Wales, Australia

His professor, astrophysicist Duncan Lorimer, had asked him to search for a recently discovered type of ultra-rapid pulsar dubbed RRAT. But buried among the mountain of data, Narkevic found an odd signal that seemed to come from the direction of our neighboring galaxy, the Small Magellanic Cloud.

Small Magellanic Cloud. NASA/ESA Hubble and ESO/Digitized Sky Survey 2

The signal was unlike anything Lorimer had encountered before. Although it flashed only briefly, for just five milliseconds, it was 10 billion times brighter than a typical pulsar in the Milky Way galaxy. It was emitting in a millisecond as much energy as the sun emits in a month.

What Narkevic and Lorimer found was the first of many bizarre, ultra-powerful flashes detected by our telescopes. For years the flashes first seemed either improbable or at least vanishingly rare. But now researchers have observed more than 80 of these Fast Radio Bursts, or FRBs. While astronomers once thought that what would be later dubbed the “Lorimer Burst” was a one-off, they now agree that there’s probably one FRB happening somewhere in the universe nearly every second.

And the reason for this sudden glut of discoveries? Aliens. Well, not aliens per se, but the search for them. Among the scores of astronomers and researchers working tirelessly to uncover these enigmatic signals is an eccentric Russian billionaire who, in his relentless hunt for extraterrestrial life, has ended up partly bankrolling one of the most complex and far-reaching scans of our universe ever attempted.

Ever since Narkevic spotted the first burst, scientists have been wondering what could produce these mesmerizing flashes in deep space. The list of possible sources is long, ranging from the theoretical to the simply unfathomable: colliding black holes, white holes, merging neutron stars, exploding stars, dark matter, rapidly spinning magnetars, and malfunctioning microwaves have all been proposed as possible sources.

While some theories can now be rejected, many live on. Finally though, after more than a decade of searching, a new generation of telescopes is coming online that could help researchers to understand the mechanism that is producing these ultra-powerful bursts. In two recent back-to-back papers, one published last week and one today, two different arrays of radio antennas—the Australian Square Kilometer Array Pathfinder (ASKAP) and Caltech’s Deep Synoptic Array 10 at the Owens Valley Radio Observatory (OVRO) in the US—have for the first time ever been able to precisely locate two different examples of these mysterious one-off FRBs.

Australian Square Kilometre Array Pathfinder (ASKAP) is a radio telescope array located at Murchison Radio-astronomy Observatory (MRO) in the Australian Mid West. ASKAP consists of 36 identical parabolic antennas, each 12 metres in diameter, working together as a single instrument with a total collecting area of approximately 4,000 square metres.

Caltech’s Deep Synoptic Array 10 dish array at Owens Valley Radio Observatory, near Big Pine, California USA, Altitude 1,222 m (4,009 ft

Physicists are now expecting that two other new telescopes—Chime (the Canadian Hydrogen Intensity Mapping Experiment) in Canada and MeerKAT in South Africa—will finally tell us what produces these powerful radio bursts.

CHIME Canadian Hydrogen Intensity Mapping Experiment -A partnership between the University of British Columbia, the University of Toronto, McGill University, Yale and the National Research Council in British Columbia, at the Dominion Radio Astrophysical Observatory in Penticton, British Columbia, CA Altitude 545 m (1,788 ft)

SKA Meerkat telescope(s), 90 km outside the small Northern Cape town of Carnarvon, SA

But Narkevic’s and Lorimer’s discovery nearly got binned. For a few months after they first spotted the unusually bright burst, it looked like the findings wouldn’t make it any further than Lorimer’s office walls, just beyond the banks of the Monongahela River that slices through the city of Morgantown in West Virginia.

Soon after detecting the burst, Lorimer asked his former graduate adviser Matthew Bailes, an astronomer at Swinburne University in Melbourne, to help him plot the signal—which to astronomers is now a famous and extremely bright energy peak, rising well above the power of any known pulsar. The burst seemed to come from much, much further away than where the Parkes telescope would usually find pulsars; in this case, probably from another galaxy, potentially billions of light-years away.

“It just looked beautiful. I was like, ‘Whoa, that’s amazing.’ We nearly fell off our chairs,” recalls Bailes. “I had trouble sleeping that night because I thought if this thing is really that far away and that insanely bright, it’s an amazing discovery. But it better be right.”

Within weeks, Lorimer and Bailes crafted a paper and sent it to Nature—and swiftly received a rejection. In a reply, a Nature editor raised concerns that there had been only one event, which appeared way brighter than seemed possible. Bailes was disappointed, but he had been in a worse situation before. Sixteen years earlier, he and fellow astronomer Andrew Lyne had submitted a paper claiming to have spotted the first ever planet orbiting another star—and not just any star but a pulsar. The scientific discovery turned out to be a fluke of their telescope. Months later, Lyne had to stand up in front of a large audience at an American Astronomical Society conference and announce their mistake. “It’s science. Anything can happen,” says Bailes. This time around, Bailes and Lorimer were certain that they had it right and decided to send their FRB paper to another journal, Science.

After it was published, the paper immediately stirred interest; some scientists even wondered whether the mysterious flash was an alien communication. This wasn’t the first time that astronomers had reached for aliens as the answer for a seemingly inexplicable signal from space; in 1967, when researchers detected what turned out to be the first pulsar, they also wondered whether it could be a sign of intelligent life.

Just like Narkevic decades later, Cambridge graduate student Jocelyn Bell had stumbled across a startling signal in the reams of data gathered by a radio array in rural Cambridgeshire.

Women in STEM – Dame Susan Jocelyn Bell Burnell

Dame Susan Jocelyn Bell Burnell, discovered pulsars with radio astronomy. Jocelyn Bell at the Mullard Radio Astronomy Observatory, Cambridge University, taken for the Daily Herald newspaper in 1968. Denied the Nobel.

Dame Susan Jocelyn Bell Burnell at work on first plusar chart 1967 pictured working at the Four Acre Array in 1967. Image courtesy of Mullard Radio Astronomy Observatory.

Dame Susan Jocelyn Bell Burnell 2009

Dame Susan Jocelyn Bell Burnell (1943 – ), still working from http://www. famousirishscientists.weebly.com

Not much of the array is left today; in the fields near the university where it once stood, there’s an overgrown hedge, hiding a collection of wonky, sad-looking wooden poles that were once covered in a web of copper wire designed to detect radio waves from faraway sources. The wire has long been stolen and sold on to scrap metal dealers.

“We did seriously consider the possibility of aliens,” Bell says, now an emeritus professor at Oxford University. Tellingly, the first pulsar was half-jokingly dubbed LGM-1 —for little green men. With only half a year left until the defense of her PhD thesis, she was less than thrilled that “some silly lot of little green men” were using her telescope and her frequency to signal to planet Earth. Why would aliens “be using a daft technique signaling to what was probably still a rather inconspicuous planet?” she once wrote in an article for Cosmic Search Magazine.

Just a few weeks later, however, Bell spotted a second pulsar, and then a third just as she got engaged, in January 1968. Then, as she was defending her thesis and days before her wedding, she discovered a fourth signal in yet another part of the sky. Proof that pulsars had to be a natural phenomenon of an astrophysical origin, not a signal from intelligent life. Each new signal made the prospect even more unlikely that groups of aliens, separated by the vastness of the space, were somehow coordinating their efforts to send a message to an uninteresting hunk of rock on the outskirts of the Milky Way.

Lorimer wasn’t so lucky. After the first burst, six years would pass without another detection. Many scientists began to lose interest. The microwave explanation persisted for a while, says Lorimer, as skeptics sneered at the notion of finding a burst that was observed only once. It didn’t help that in 2010 Parkes detected 16 similar pulses, which were quickly proven to be indeed caused by the door of a nearby microwave oven that had been opened suddenly during its heating cycle.

Yuri Milner on stage with Mark Zuckerberg at a Breakthrough Prize event in 2017. Kimberly White/Getty Images

When Avi Loeb first read of Lorimer’s unusual discovery, he too wondered if it was nothing more than the result of some errant wiring or miscalibrated computer. The chair of the astronomy department at Harvard happened to be in Melbourne in November 2007, just as Lorimer’s and Bailes’ paper appeared in Science, so he had a chance to discuss the odd burst with Bailes. Loeb thought the radio flash was a compelling enigma—but not much more than that.

Still, that same year Loeb wrote a theoretical paper arguing that radio telescopes built to detect very specific hydrogen emissions from the early universe would also be able to eavesdrop on radio signals from alien civilizations up to about 10 light-years away. “We have been broadcasting for a century—so another civilization with the same arrays can see us from a distance out to 50 light-years,” was Loeb’s reasoning. He followed up with another paper on the search for artificial lights in the solar system. There, Loeb showed that a city as bright as Tokyo could be detected with the Hubble Space Telescope even if it was located right at the edge of the solar system. In yet another paper he argued how to detect industrial pollution in planetary atmospheres.

Ever since he was a little boy growing up in Israel, Loeb has been fascinated with life—on Earth and elsewhere in the universe. “Currently, the search for microbial life is part of the mainstream in astronomy—people are looking for the chemical fingerprints of primitive life in the atmosphere of exoplanets,” says Loeb, who first dabbled in philosophy before his degree in physics.

But the search for intelligent life beyond Earth should also be part of the mainstream, he argues. “There is a taboo, it’s a psychological and sociological problem that people have. It’s because there is the baggage of science fiction and UFO reports, both of which have nothing to do with what actually goes on out there in space,” he adds. He’s frustrated with having to explain—and defend—his point of view. After all, he says, billions have been poured into the search for dark matter over decades with zero results. Should the search for extraterrestrial intelligence, more commonly known as SETI, be regarded as even more fringe than this fruitless search?

Lorimer didn’t follow Loeb’s SETI papers closely. After six long and frustrating years, his luck turned in 2013, when a group of his colleagues—including Bailes—spotted four other bright radio flashes in Parkes’ data. Lorimer felt vindicated and relieved. More detections followed and the researchers were on a roll: At long last, FRBs had been confirmed as a real thing. After the first event was dubbed “Lorimer’s Burst,” it swiftly made it onto the physics and astronomy curricula of universities around the globe. In physics circles, Lorimer was elevated to the position of a minor celebrity.

Keeping an eye on events from a distance was Loeb. One evening in February 2014, at a dinner in Boston, he started chatting to a charismatic Russian-Israeli called Yuri Milner, a billionaire technology investor with a background in physics and a well-known name in Silicon Valley. Ever since he could remember, Milner had been fascinated with life beyond Earth, a subject close to Loeb’s heart; the two instantly hit it off.

Milner came to see Loeb again in May the following year, at Harvard, and asked the academic how long it would take to travel to Alpha Centauri, the star system closest to Earth.

Centauris Alpha Beta Proxima 27, February 2012. Skatebiker

Loeb replied he would need half a year to identify the technology that would allow humans to get there in their lifetime. Milner then asked Loeb to lead Breakthrough Starshot, one of five Breakthrough Initiatives the Russian oligarch was about to announce in a few weeks—backed by $100 million of his own money and all designed to support SETI.

Breakthrough Starshot Initiative

Breakthrough Starshot

ESO 3.6m telescope & HARPS at LaSilla, 600 km north of Santiago de Chile at an altitude of 2400 metres.

SPACEOBS, the San Pedro de Atacama Celestial Explorations Observatory is located at 2450m above sea level, north of the Atacama Desert, in Chile, near to the village of San Pedro de Atacama and close to the border with Bolivia and Argentina

SNO Sierra Nevada Observatory is a high elevation observatory 2900m above the sea level located in the Sierra Nevada mountain range in Granada Spain and operated maintained and supplied by IAC

Teide Observatory in Tenerife Spain, home of two 40 cm LCO telescopes

Observatori Astronòmic del Montsec (OAdM), located in the town of Sant Esteve de la Sarga (Pallars Jussà), 1,570 meters on the sea level

Bayfordbury Observatory,approximately 6 miles from the main campus of the University of Hertfordshire

Fast-forward six months, and at the end of December 2015 Loeb got a call asking him to prepare a presentation summarizing his recommended technology for the Alpha Centauri trip. Loeb was visiting Israel and about to head on a weekend trip to a goat farm in the southern part of the country. “The following morning, I was sitting next to the reception of the farm—the only location with internet connectivity—and typing the PowerPoint presentation that contemplated a lightsail technology for Yuri’s project,” says Loeb. He presented it at Milner’s home in Moscow two weeks later, and the Breakthrough Initiatives were announced with fanfare in July 2015.

The initiatives were an adrenaline shot in the arm of the SETI movement—the largest ever private cash injection into the search for aliens. One of the five projects is Breakthrough Listen, which was championed, among others, by the famous astronomer Stephen Hawking (who has died since) and British astronomer royal Martin Rees.

Breakthrough Listen Project

UC Observatories Lick Autmated Planet Finder, fully robotic 2.4-meter optical telescope at Lick Observatory, situated on the summit of Mount Hamilton, east of San Jose, California, USA

GBO radio telescope, Green Bank, West Virginia, USA

CSIRO/Parkes Observatory, located 20 kilometres north of the town of Parkes, New South Wales, Australia

SKA Meerkat telescope, 90 km outside the small Northern Cape town of Carnarvon, SA

Newly added

CfA/VERITAS, a major ground-based gamma-ray observatory with an array of four 12m optical reflectors for gamma-ray astronomy in the GeV – TeV energy range. Located at Fred Lawrence Whipple Observatory, Mount Hopkins, Arizona, US in AZ, USA, Altitude 2,606 m (8,550 ft)

Echoing the film Contact, with Jodie Foster playing an astronomer listening out for broadcasts from aliens (loosely based on real-life SETI astronomer Jill Tarter), the project uses radio telescopes around the world to look for any signals from extraterrestrial intelligence.

Jill Tarter Image courtesy of Jill Tarter

After the Breakthrough Initiatives were announced, Milner’s money quickly got invested into the deployment of cutting-edge technology—such as computer storage and new receivers—at existing radio telescopes, including Green Bank in West Virginia and Parkes in Australia; whether the astronomers using these observatories believed in alien life or not, they welcomed the investment with open arms. It didn’t take long to receive the first scientific returns.

After the Breakthrough Initiatives were announced, Milner’s money quickly got invested into the deployment of cutting-edge technology—such as computer storage and new receivers—at existing radio telescopes, including Green Bank in West Virginia and Parkes in Australia; whether the astronomers using these observatories believed in alien life or not, they welcomed the investment with open arms. It didn’t take long to receive the first scientific returns.

In August 2015 one of the previously spotted FRBs decided to make a repeat appearance, triggering headlines worldwide because it was so incredibly powerful, brighter than the Lorimer Burst and any other FRB. It was dubbed “the repeater” and is also known as the Spitler Burst, because it was first discovered by astronomer Laura Spitler of the Max Planck Institute for Radio Astronomy in Bonn, Germany.

Max Planck Institute for Radio Astronomy

Max Planck Institute for Radio Astronomy Bonn Germany

Over the next few months, the burst flashed many more times, not regularly, but often enough to allow researchers to determine its host galaxy and consider its possible source—likely a highly magnetized, young, rapidly spinning neutron star (or magnetar).

This localization was done with the Very Large Array (VLA), a group of 27 radio dishes in New Mexico that feature heavily in the film Contact. But the infrastructure at Green Bank Telescope upgraded by Breakthrough Listen caught the repeating flashes many more times, says Lorimer—allowing researchers to study its host galaxy more in detail. “It’s wonderful—they have a mission to find ET, but along the way they want to show that this is producing other useful results for the scientific community,” he adds. Detecting FRBs has quickly become one of the main objectives of Breakthrough Listen.

Netting the repeater was both a boon and a hindrance—on the one hand, it eliminated models that cataclysmic events such as supernova explosions were causing FRBs; after all, these can happen only once. On the other hand, it deepened the mystery. The repeater lives in a small galaxy with a lot of star formation—the kind of environment where a neutron star could be born, hence the magnetar model. But what about all the other FRBs that don’t repeat?

Researchers started to think that perhaps there were different types of these bursts, each with its own source. Scientific conferences still buzz with talks of mights and might-nots, with physicists eagerly debating possible sources of FRBs in corridors and at conference bars. In March 2017, Loeb caused a media frenzy by suggesting that FRBs could actually be of alien origin—solar-powered radio transmitters that might be interstellar light sails pushing huge spaceships across galaxies.

That Parkes is part of the SETI project is obvious to any visitor. Walking up the flight of stairs to the circular operating tower below the dish, every button, every door, and every wall nostalgically screams 1960s, until you reach the control room full of modern screens where astronomers remotely control the antenna to observe pulsars.

Up another flight of stairs is the data storage room, stacked with columns and columns of computer drives full of blinking lights. One thick column of hard drives is flashing neon blue, put there by Breakthrough Listen as part of a cutting-edge recording system designed to help astronomers search for every possible radio signal in 12 hours of data, much more than ever before. Bailes, who now splits his time between FRB search and Breakthrough Listen, takes a smiling selfie in front of Milner’s drives.

While many early FRB discoveries were made with veteran telescopes—single mega dishes like Parkes and Green Bank—new telescopes, some with the financial backing of Breakthrough Listen, are now revolutionizing the FRB field.

Deep in South African’s semi-desert region of the Karoo, eight hours by car from Cape Town, stands an array of 64 dishes, permanently tracking space. They are much smaller than their mega-dish cousins, and all work in unison. This is MeerKAT [above], another instrument in Breakthrough Listen’s growing worldwide network of giant telescopes. Together with a couple of other next-generation instruments, this observatory might hopefully tell us one day, probably in the next decade, what FRBs really are.

The name MeerKAT means “More KAT,” a follow up to KAT 7, the Karoo Array Telescope of seven antennas—although real meerkats do lurk around the remote site, sharing the space with wild donkeys, horses, snakes, scorpions and kudus, moose-sized mammals with long, spiraling antlers. Visitors to MeerKAT are told to wear safety leather boots with steel toes as a precaution against snakes and scorpions. They’re also warned about the kudus, which are very protective of their calves and recently attacked the pickup truck of a security guard, turning him and his car over. Around MeerKAT there is total radio silence; all visitors have to switch off their phones and laptops. The only place with connectivity is an underground “bunker” shielded by 30-centimeter-thick walls and a heavy metal door to protect the sensitive antennas from any human-made interference.

MeerKAT is one of the two precursors to a much bigger future radio observatory—the SKA, or Square Kilometer Array.

SKA Square Kilometer Array

SKA South Africa

Once SKA is complete, scientists will have added another 131 antennas in the Karoo. The first SKA dish has just been shipped to the MeerKAT site from China. Each antenna will take several weeks to assemble, followed by a few more months of testing to see whether it actually works the way it should. If all goes well, more will be commissioned, built, and shipped to this faraway place, where during the day the dominant color is brown; as the sun sets, however, the MeerKAT dishes dance in an incredible palette of purples, reds, and pinks, as they welcome the Milky Way stretching its starry path just above. MeerKAT will soon be an incredible FRB machine, says Bailes.

There is another SKA precursor—ASKAP in Australia.

Australian Square Kilometre Array Pathfinder (ASKAP) is a radio telescope array located at Murchison Radio-astronomy Observatory (MRO) in the Australian Mid West. ASKAP consists of 36 identical parabolic antennas, each 12 metres in diameter, working together as a single instrument with a total collecting area of approximately 4,000 square metres.

Back in 2007, when Lorimer was mulling over the Nature rejection, Ryan Shannon was finishing his PhD in physics at Cornell University in New York—sharing the office with Laura Spitler, who would later discover the Spitler Burst. Shannon had come to the US from Canada, growing up in a small town in British Columbia. About half an hour drive from his home is the Dominion and Radio Astronomical Observatory (DRAO)—a relatively small facility that was involved in building equipment for the VLA.

NRAO/Karl V Jansky Expanded Very Large Array, on the Plains of San Agustin fifty miles west of Socorro, NM, USA, at an elevation of 6970 ft (2124 m)

Subconsciously, says Shannon, DRAO must have impacted his choice of career. And it was at DRAO that a few years later a totally new telescope—Chime [above]—would be built that would greatly impact the nascent field of FRB research. But in 2007 that was still to come. After graduating from Cornell in 2011, Shannon decided not to stay close to home—“something my mum would’ve wanted.” Instead, he moved to Australia and ultimately to Swinburne University on the outskirts of Melbourne.

Shannon joined Bailes’ team in 2017—and by then astronomers had begun to understand why they weren’t detecting more FRBs, even though they were already estimating that these flashes were happening hundreds of times every day, if not more. “Our big radio telescopes don’t have wide fields of view, they can’t see the entire sky—that’s why we missed nearly all FRBs in the first decade of realizing these things exist,” says Shannon.

When he, Bailes, and other FRB hunters saw the ultra-bright repeater, the Spitler Burst, they understood that there were fast radio bursts which could be found even without gigantic telescopes like Parkes, by using instruments that have a wider field of view. So they started building ASKAP [above]—a new observatory conceived in 2012 and recently completed in the remote Australian outback. It sports 36 dishes with a 12-meter diameter each, and just like with MeerKAT, they all work together.

To get to ASKAP, in a very sparsely populated area in the Murchison Shire of Western Australia, one has to first fly to Perth, change for a smaller plane bound for Murchison, then squeeze into a really tiny single propeller plane, or drive for five hours across 150 kilometers of dirt roads. “When it rains, it turns to mud, and you can’t drive there,” says Shannon, who went to the ASKAP site twice, to introduce the local indigenous population to the new telescope constructed—with permission—on their land and see the remote, next-generation ultra-sensitive radio observatory for himself.

MeerKAT and ASKAP bring two very different technological approaches to the hunt for FRBs. Both observatories look at the southern sky, which makes it possible to see the Milky Way’s bright core much better than in the northern hemisphere; they complement old but much upgraded observatories like Parkes and Arecibo in South America. But the MeerKAT dishes have highly sensitive receivers which are able to detect very distant objects, while ASKAP’s novel multi-pixel receivers on each dish offer a much wider field of view, enabling the telescope to find nearby FRBs more often.

“ASKAP’s dishes are less sensitive, but we can observe a much larger portion of the sky,” says Shannon. “So ASKAP is going to be able to see things that are usually intrinsically brighter.” Together, the two precursors will be hunting for different parts of the FRB population—since “you want to understand the entire population to know the big picture.”

MeerKAT only started taking data in February, but ASKAP has been busy scanning the universe for FRBs for a few years now. Not only has it already spotted about 30 new bursts, but in a new paper just released in Science, Shannon and colleagues have detailed a new way to localize them despite their short duration, which is a big and important step toward being able to determine what triggers this ultra-bright radiation. Think of ASKAP’s antennas as the eye of a fly; they can scan a wide patch of the sky to spot as many bursts as possible, but the antennas can all be made to point instantly in the same direction. This way, they make an image of the sky in real time, and spot a millisecond-long FRB as it washes over Earth. That’s what Shannon and his colleagues have done, and for the first time ever, managed to net one burst they named FRB 180924 and pinpoint its host galaxy, some 4 billion light-years away, all in real time.

Another team, at Caltech’s Owens Valley Radio Observatory (OVRO) in the Sierra Nevada mountains in California, have also just caught a new burst and traced it back to its source, a galaxy 7.9 billion light years away.

Caltech’s Deep Synoptic Array 10 dish array at Owens Valley Radio Observatory, near Big Pine, California USA, Altitude 1,222 m (4,009 ft

And just like Shannon, they didn’t do it with a single dish telescope but a recently built array of 10 4.5-meter antennas called the Deep Synoptic Array-10. The antennas act together like a mile-wide dish to cover an area on the sky the size of 150 full moons. The telescope’s software then processes an amount of data equivalent to a DVD every second. The array is a precursor for the Deep Synoptic Array that, when built by 2021, will sport 110 radio dishes, and may be able to detect and locate more than 100 FRBs every year.

What both ASKAP’s and OVRO’s teams found was that their presumably one-off bursts originated in galaxies very different from the home of the first FRB repeater. Both come from galaxies with very little star formation, similar to the Milky Way and very different from the home of the repeater, where stars are born at a rate of about a hundred times faster. The discoveries show that “every galaxy, even a run-of-the-mill galaxy like our Milky Way, can generate an FRB,” says Vikram Ravi, an astronomer at Caltech and part of the OVRO team.

But the findings also mean that the magnetar model, accepted by many as the source of the repeating burst, does not really work for these one-off flashes. Perhaps, Shannon says, ASKAP’s burst could be the result of a merger of two neutron stars, similar to the one spotted two years ago by the gravitational wave detectors LIGO and Virgo in the US and Italy, because both host galaxies are very similar. “It’s a bit spooky that way,” says Shannon. One thing is clear though, he adds: The findings show that there is likely more than one type of FRBs.

Back in Shannon’s hometown in Canada, the excitement has also been growing exponentially because of CHIME. Constructed at the same time as MeerKAT and ASKAP, this is a very different observatory; it has no dishes but antennas in the form of long buckets designed to capture light. In January, the CHIME team reported the detection of the second FRB repeater and 12 non-repeating FRBs. CHIME is expected to find many, many more bursts, and with ASKAP, MeerKAT and CHIME working together, astronomers hope to understand the true nature of the enigmatic radio flashes very soon.

But will they fulfill Milner’s dream and successfully complete SETI, the search for extraterrestrial intelligence? Lorimer says that scientists hunting for FRBs and pulsars have for decades been working closely with colleagues involved in SETI projects.

After all, Loeb’s models for different—alien—origins of FRBs are not fundamentally wrong. “The energetics when you consider what we know from the observations are consistent and there’s nothing wrong with that,” says Lorimer. “And as part of the scientific method, you definitely want to encourage those ideas.” He personally prefers to find the simplest natural explanation for the phenomena he observes in space—but until we manage to directly observe the source of these FRBs, all theoretical ideas should stand, as long as they are scientifically sound—whether they involve aliens or not.

Any image repeats in this post were required for complete coverage.

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Totally missing from this article on SETI-

SETI Institute

SETI/Allen Telescope Array situated at the Hat Creek Radio Observatory, 290 miles (470 km) northeast of San Francisco, California, USA, Altitude 986 m (3,235 ft)

UCSC alumna Shelley Wright, now an assistant professor of physics at UC San Diego, discusses the dichroic filter of the NIROSETI instrument. (Photo by Laurie Hatch).jpg

Shelley Wright of UC San Diego, with NIROSETI, developed at U Toronto, at the 1-meter Nickel Telescope at Lick Observatory at UC Santa Cruz

Laser SETI, the future of SETI Institute research

SETI@home, a BOINC project originated in the Space Science Lab at UC Berkeley

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From UC Santa Cruz: “Breakthrough Listen launches new optical search with VERITAS Telescope Array”

From UC Santa Cruz

July 17, 2019
Tim Stephens
stephens@ucsc.edu

SCIPP (Santa Cruz Institute for Particle Physics) physicist David Williams will help lead effort using four 12-meter telescopes to search for nanosecond flashes of light from extraterrestrial civilizations.

The Breakthrough Listen initiative to find signs of intelligent life in the universe will collaborate with the VERITAS Collaboration in the search for technosignatures, signs of technology developed by intelligent life beyond the Earth.

Joining the Breakthrough Listen initiative’s ongoing radio frequency survey and spectroscopic optical laser survey, VERITAS (the Very Energetic Radiation Imaging Telescope Array System) will search for pulsed optical beacons with its array of four 12-meter telescopes at the Fred Lawrence Whipple Observatory in Amado, Arizona.

VERITAS is the world’s most powerful telescope array for studying high-energy astrophysics with gamma rays. It detects gamma rays coming from space by looking for the extremely brief flashes of blue “Cherenkov” light they create when they hit the top of the Earth’s atmosphere.

VERITAS will look for pulsed optical beacons with durations as short as several nanoseconds. Over such timescales, artificial beacons could easily outshine any stars that lie in the same direction on the sky. The use of all four telescopes simultaneously allows for very effective discrimination against false positive detections. The VERITAS Collaboration has previously published observations of the mysteriously dimming Boyajian’s Star in search of such optical pulses. The new program of VERITAS observations will provide complementary searches for optical pulse signatures of many more stars from the primary Breakthrough Listen star list.

“It is impressive how well-suited the VERITAS telescopes are for this project, since they were built only with the purpose of studying very-high-energy gamma rays in mind,” said David Williams, adjunct professor of physics at UC Santa Cruz and the Santa Cruz Institute for Particle Physics (SCIPP) and a member of the VERITAS collaboration.

Breakthrough Listen’s search for optical technosignatures with VERITAS will be led by Williams at UCSC and Jamie Holder of the University of Delaware, in collaboration with the Listen team at UC Berkeley’s SETI Research Center led by Andrew Siemion.

“When it comes to intelligent life beyond Earth, we don’t know where it exists or how it communicates,” said Yuri Milner, founder of the Breakthrough Initiatives. “So our philosophy is to look in as many places, and in as many ways, as we can. VERITAS expands our range of observation even further.”

“Breakthrough Listen is already the most powerful, comprehensive, and intensive search yet undertaken for signs of intelligent life beyond Earth,” Siemion said. “Now, with the addition of VERITAS, we’re sensitive to an important new class of signals: fast optical pulses. Optical communication has already been used by NASA to transmit high definition images to Earth from the moon, so there’s reason to believe that an advanced civilization might use a scaled-up version of this technology for interstellar communication.”

If a laser comparable to the most powerful lasers on Earth (delivering about 500 terawatts in a pulse lasting a few nanoseconds) were situated at the distance of Boyajian’s Star and pointed in our direction, VERITAS could detect it. But most of the stars in the Listen target list are 10 to 100 times closer than Boyajian’s Star, meaning that the new search will be sensitive to pulses a factor 100 to 10,000 times fainter still.

“Using the huge mirror area of the four VERITAS telescopes will allow us to search for these extremely faint optical flashes in the night sky, which could correspond to signals from an extraterrestrial civilization,” said Holder.

Breakthrough Listen Project

UC Observatories Lick Autmated Planet Finder, fully robotic 2.4-meter optical telescope at Lick Observatory, situated on the summit of Mount Hamilton, east of San Jose, California, USA

GBO radio telescope, Green Bank, West Virginia, USA

CSIRO/Parkes Observatory, located 20 kilometres north of the town of Parkes, New South Wales, Australia

SKA Meerkat telescope, 90 km outside the small Northern Cape town of Carnarvon, SA

Newly added

CfA/VERITAS, a major ground-based gamma-ray observatory with an array of four 12m optical reflectors for gamma-ray astronomy in the GeV – TeV energy range. Located at Fred Lawrence Whipple Observatory, Mount Hopkins, Arizona, US in AZ, USA, Altitude 2,606 m (8,550 ft)

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UCSC Lick Observatory, Mt Hamilton, in San Jose, California, Altitude 1,283 m (4,209 ft)

.

Shane Telescope at UCO Lick Observatory, UCSC

Lick Automated Planet Finder telescope, Mount Hamilton, CA, USA

The University of California, Santa Cruz, opened in 1965 and grew, one college at a time, to its current (2008-09) enrollment of more than 16,000 students. Undergraduates pursue more than 60 majors supervised by divisional deans of humanities, physical & biological sciences, social sciences, and arts. Graduate students work toward graduate certificates, master’s degrees, or doctoral degrees in more than 30 academic fields under the supervision of the divisional and graduate deans. The dean of the Jack Baskin School of Engineering oversees the campus’s undergraduate and graduate engineering programs.

UCSC is the home base for the Lick Observatory.

Lick Observatory’s Great Lick 91-centimeter (36-inch) telescope housed in the South (large) Dome of main building

Search for extraterrestrial intelligence expands at Lick Observatory
New instrument scans the sky for pulses of infrared light
March 23, 2015
By Hilary Lebow

The NIROSETI instrument saw first light on the Nickel 1-meter Telescope at Lick Observatory on March 15, 2015. (Photo by Laurie Hatch) UCSC Lick Nickel telescope

Astronomers are expanding the search for extraterrestrial intelligence into a new realm with detectors tuned to infrared light at UC’s Lick Observatory. A new instrument, called NIROSETI, will soon scour the sky for messages from other worlds.

“Infrared light would be an excellent means of interstellar communication,” said Shelley Wright, an assistant professor of physics at UC San Diego who led the development of the new instrument while at the University of Toronto’s Dunlap Institute for Astronomy & Astrophysics.

Wright worked on an earlier SETI project at Lick Observatory as a UC Santa Cruz undergraduate, when she built an optical instrument designed by UC Berkeley researchers. The infrared project takes advantage of new technology not available for that first optical search.

Infrared light would be a good way for extraterrestrials to get our attention here on Earth, since pulses from a powerful infrared laser could outshine a star, if only for a billionth of a second. Interstellar gas and dust is almost transparent to near infrared, so these signals can be seen from great distances. It also takes less energy to send information using infrared signals than with visible light.

Frank Drake, professor emeritus of astronomy and astrophysics at UC Santa Cruz and director emeritus of the SETI Institute, said there are several additional advantages to a search in the infrared realm.

“The signals are so strong that we only need a small telescope to receive them. Smaller telescopes can offer more observational time, and that is good because we need to search many stars for a chance of success,” said Drake.

The only downside is that extraterrestrials would need to be transmitting their signals in our direction, Drake said, though he sees this as a positive side to that limitation. “If we get a signal from someone who’s aiming for us, it could mean there’s altruism in the universe. I like that idea. If they want to be friendly, that’s who we will find.”

Scientists have searched the skies for radio signals for more than 50 years and expanded their search into the optical realm more than a decade ago. The idea of searching in the infrared is not a new one, but instruments capable of capturing pulses of infrared light only recently became available.

“We had to wait,” Wright said. “I spent eight years waiting and watching as new technology emerged.”

Now that technology has caught up, the search will extend to stars thousands of light years away, rather than just hundreds. NIROSETI, or Near-Infrared Optical Search for Extraterrestrial Intelligence, could also uncover new information about the physical universe.

“This is the first time Earthlings have looked at the universe at infrared wavelengths with nanosecond time scales,” said Dan Werthimer, UC Berkeley SETI Project Director. “The instrument could discover new astrophysical phenomena, or perhaps answer the question of whether we are alone.”

NIROSETI will also gather more information than previous optical detectors by recording levels of light over time so that patterns can be analyzed for potential signs of other civilizations.

“Searching for intelligent life in the universe is both thrilling and somewhat unorthodox,” said Claire Max, director of UC Observatories and professor of astronomy and astrophysics at UC Santa Cruz. “Lick Observatory has already been the site of several previous SETI searches, so this is a very exciting addition to the current research taking place.”

NIROSETI will be fully operational by early summer and will scan the skies several times a week on the Nickel 1-meter telescope at Lick Observatory, located on Mt. Hamilton east of San Jose.

The NIROSETI team also includes Geoffrey Marcy and Andrew Siemion from UC Berkeley; Patrick Dorval, a Dunlap undergraduate, and Elliot Meyer, a Dunlap graduate student; and Richard Treffers of Starman Systems. Funding for the project comes from the generous support of Bill and Susan Bloomfield.

From National Radio Astronomy Observatory: “New Method May Resolve Difficulty in Measuring Universe’s Expansion”

From National Radio Astronomy Observatory

Astronomers using National Science Foundation (NSF) radio telescopes have demonstrated how a combination of gravitational-wave and radio observations, along with theoretical modeling, can turn the mergers of pairs of neutron stars into a “cosmic ruler” capable of measuring the expansion of the Universe and resolving an outstanding question over its rate.

The astronomers used the NSF’s Very Long Baseline Array (VLBA), the Karl G. Jansky Very Large Array (VLA) and the Robert C. Byrd Green Bank Telescope (GBT) to study the aftermath of the collision of two neutron stars that produced gravitational waves detected in 2017.

NRAO/VLBA

NRAO/Karl V Jansky Expanded Very Large Array, on the Plains of San Agustin fifty miles west of Socorro, NM, USA, at an elevation of 6970 ft (2124 m)

Green Bank Radio Telescope, West Virginia, USA, now the center piece of the GBO, Green Bank Observatory, being cut loose by the NSF

This event offered a new way to measure the expansion rate of the Universe, known by scientists as the Hubble Constant. The expansion rate of the Universe can be used to determine its size and age, as well as serve as an essential tool for interpreting observations of objects elsewhere in the Universe.

Two leading methods of determining the Hubble Constant use the characteristics of the Cosmic Microwave Background, the leftover radiation from the Big Bang, or a specific type of supernova explosions, called Type Ia, in the distant Universe. However, these two methods give different results.

“The neutron star merger gives us a new way of measuring the Hubble Constant, and hopefully of resolving the problem,” said Kunal Mooley, of the National Radio Astronomy Observatory (NRAO) and Caltech.

The technique is similar to that using the supernova explosions. Type Ia supernova explosions are thought to all have an intrinsic brightness which can be calculated based on the speed at which they brighten and then fade away. Measuring the brightness as seen from Earth then tells the distance to the supernova explosion. Measuring the Doppler shift of the light from the supernova’s host galaxy indicates the speed at which the galaxy is receding from Earth. The speed divided by the distance yields the Hubble Constant. To get an accurate figure, many such measurements must be made at different distances.

When two massive neutron stars collide, they produce an explosion and a burst of gravitational waves. The shape of the gravitational-wave signal tells scientists how “bright” that burst of gravitational waves was. Measuring the “brightness,” or intensity of the gravitational waves as received at Earth can yield the distance.

“This is a completely independent means of measurement that we hope can clarify what the true value of the Hubble Constant is,” Mooley said.

However, there’s a twist. The intensity of the gravitational waves varies with their orientation with respect to the orbital plane of the two neutron stars. The gravitational waves are stronger in the direction perpendicular to the orbital plane, and weaker if the orbital plane is edge-on as seen from Earth.

“In order to use the gravitational waves to measure the distance, we needed to know that orientation,” said Adam Deller, of Swinburne University of Technology in Australia.

Over a period of months, the astronomers used the radio telescopes to measure the movement of a superfast jet of material ejected from the explosion. “We used these measurements along with detailed hydrodynamical simulations to determine the orientation angle, thus allowing use of the gravitational waves to determine the distance,” said Ehud Nakar from Tel Aviv University.

This single measurement, of an event some 130 million light-years from Earth, is not yet sufficient to resolve the uncertainty, the scientists said, but the technique now can be applied to future neutron-star mergers detected with gravitational waves.

“We think that 15 more such events that can be observed both with gravitational waves and in great detail with radio telescopes, may be able to solve the problem,” said Kenta Hotokezaka, of Princeton University. “This would be an important advance in our understanding of one of the most important aspects of the Universe,” he added.

The international scientific team led by Hotokezaka is reporting its results in the journal Nature Astronomy.

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NRAO/Karl V Jansky VLA, on the Plains of San Agustin fifty miles west of Socorro, NM, USA

The NRAO operates a complementary, state-of-the-art suite of radio telescope facilities for use by the scientific community, regardless of institutional or national affiliation: the Very Large Array (VLA), and the Very Long Baseline Array (VLBA)*.

ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

Access to ALMA observing time by the North American astronomical community will be through the North American ALMA Science Center (NAASC).

NRAO VLBA

NRAO/VLBA

*The Very Long Baseline Array (VLBA) comprises ten radio telescopes spanning 5,351 miles. It’s the world’s largest, sharpest, dedicated telescope array. With an eye this sharp, you could be in Los Angeles and clearly read a street sign in New York City!

Astronomers use the continent-sized VLBA to zoom in on objects that shine brightly in radio waves, long-wavelength light that’s well below infrared on the spectrum. They observe blazars, quasars, black holes, and stars in every stage of the stellar life cycle. They plot pulsars, exoplanets, and masers, and track asteroids and planets.

And the future Expanded Very Large Array (EVLA).

From COSMOS Magazine: “A decade waiting (and working), then two FRBs nailed in a week”

From COSMOS Magazine

06 July 2019
Richard A Lovett

But Australian and US astronomers took different approaches.

An artist’s impression of Australia’s ASKAP radio telescope observing fast radio bursts.
OZGRAV, SWINBURNE UNIVERSITY OF TECHNOLOGY.

In less than a week as June became July, two teams of radio astronomers – one in Australia, the other in the US – announced they had independently accomplished a decade-long astronomical quest: identifying the sources of powerful blasts of intergalactic radiation known as fast radio bursts (FRBs).

FRBs are enormous blazes of radio energy that in a few milliseconds can broadcast as much energy in radio waves as the monthly output of the sun in all forms combined.

What causes them is unknown, but it can only be something dramatic, such as a collision between neutron stars, or even a neutron stars falling into a black hole. “For a long time, there were more theories than [known] bursts,” says Keith Bannister, an astronomer with CSIRO’s Australia Telescope National Facility (ATNF) and leader of the Australian team.

FRBs are surprisingly common, with perhaps 2000 of them pinpricking the sky every day, Bannister says, but only a tiny fraction are detectable, “because traditional radio telescopes only see a small fraction of the sky”.

Also, the vast majority are one-off events, making it incredibly difficult to figure out what galaxy they are coming from, once they are spotted.

In an effort to solve this problem, Bannister’s team equipped 36 identical 12-metre radio telescopes that together form the Australian Square Kilometre Array Pathfinder (ASKAP) in Western Australia with a “phased array feed” that allowed each dish to see 36 distinct patches of the sky at once, each about 200 times larger than the full moon.

They also upgraded their software to rapidly triangulate on an FRB via 0.1 nanosecond differences in the time it takes the signal to reach the various telescopes in the array: a method, Bannister says, that allowed them to pinpoint its origin to a precision of 1/50,000th of a degree – the width of a human hair, 200 metres away.

The US team took a different approach. Rather than retrofitting an existing telescope array, it built a new one from the ground up.

Due to the extreme brightness of FRBs, “Keith Bannister and I both realised that we can utilise relatively insensitive but wide field-of view telescopes to try to localise them,” says its leader, Vikram Ravi, a radio astronomer at California Institute of Technology, Pasadena.

His team therefore purchased 10 broad-field-of-view 4.5-meter radio antennas – instruments not much larger than the best satellite TV dishes – and laid them out in the Owens Valley of eastern California, at a total cost of under $US500,000.

Caltech Owens Valley Long Wavelength Array-currently hosts LEDA, the largest correlator ever built, Owens Valley, California, Altitude 1,222 m (4,009 ft)

“It was a shoestring experiment,” Ravi says. “I literally moved them in place and focused them by hand.” The ultimate goal, he adds, is to expand the project to include 110 such dishes.

Finding the sources of FRBs is important for two reasons. One is simply that it helps us figure out what causes them. The FRB located by Bannister’s team, for example, came not from the centre of its galaxy, but from its outskirts – “or at least its suburbs”, Bannister says. “This means our FRB wasn’t produced by a gigantic black hole at the galaxy’s centre.”

Ravi adds that both the FRBs come from mature, Milky Way style galaxies. That’s interesting because the only other FRB whose source has ever been identified – a repeating burster whose repeated bursts made it easier to localise – came from a very different type of galaxy. That one had 1000 times less mass but was in a “starburst” stage, in which it was forming new stars at an extremely rapid pace.

Based on that, one theory had been that FRBs came from the deaths of such galaxies’ most giant youthful stars, which live fast and die in blazes of glory known as superluminous supernovae.

But such gigantic explosions are uncommon in more mature galaxies, suggesting that in the case of the two FRBs identified by Bannister’s team and Ravi’s, superluminous supernovae probably didn’t play a role.

Localising the sources of FRBs is also important, Ravi says, because FRBs can be used as probes of the distribution of matter in the universe.

One of the big issues in astrophysics, he adds, is that most of the matter in the universe is invisible to us.

Much of that is dark matter, an enigmatic substance to date is detected only by its gravity, but the vast bulk of normal matter is also invisible, Ravi says. All that’s known is that it’s very hot – on the order of a million degrees or more – and very diffuse, partly contained in tenuous halos around galaxies, but possibly also dispersed throughout the intergalactic medium.

FRBs, Ravi says, offer a way to figure out where this unseen matter lies, and how it is distributed.

That’s because as the radio burst travels through this diffuse medium, different frequencies travel at slightly different speeds. It’s not a big difference, but it’s enough that an FRB signal can become stretched as it travels, with higher frequencies travelling faster, and lower frequencies travelling slower.

“We observe the burst arriving first at the high frequencies, then later at the low frequencies,” Ravi says, an effect that can stretch a millisecond FRB to nearly a second.

Different parts of the signal can also reach us by different paths, in which they start out travelling in a slightly different direction than the main part of the signal, then are refracted back into our own line of sight.

“It’s sort of like why stars twinkle,” Ravi says.

The effect is small, but it’s a sign that the medium through which the FRB signal propagated might have been “clumpy”, rather than uniformly distributed.

To figure all of this out, Ravi says, it’s really useful to know how far an FRB signal has been travelling before it reaches us (and to know how many other galaxies it has passed close to. That’s another reason why it’s useful to locate the source galaxies of as many such signals as possible.

Shami Chatterjee, a radio astronomer at Cornell University, Ithaca, New York, and leader of the team that located the source of the repeating FRB, agrees.

Bannister’s find (and by extension, Ravi’s), he says, is “a magnificent technical achievement” that should, among other things, open the floodgates to more such findings, allowing FRBs to live up to their promise as probes of the intergalactic medium.

“Once we have a few dozen,” he says, “FRBs will be one of the only viable probes of the intergalactic medium.”

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From The Register: ” Science Crikey, that’s FAST: China clocks 84 pulsars in 2 years using world’s largest radio telescope”

From The Register

The Five-hundred-meter Aperture Spherical Radio Telescope. Image: Chinese Academy of Sciences

The world’s largest single-dish radio telescope, an enormous white circle half a kilometre in diameter, has helped scientists uncover 84 new pulsars since it began collecting data two years ago.

Jiang Peng, chief engineer at the Five-hundred-meter Aperture Spherical Radio Telescope (FAST) in Guizhou Province, southwest China, revealed that number to Xinhua News, the official mouthpiece of the Communist Party of China, on Wednesday.

Pulsars are leftover remnants of stars that have passed their shelf life and no longer burn hydrogen. The old cores have collapsed into dense white dwarfs or neutron stars.

These stars are still energetic, however, spewing regular beams of electromagnetic radiation as they rotate rapidly.

Scientists predict (CJAA) that the number of observable pulsars in our galaxy is around 70,000, but less than 3 per cent of them have been discovered so far.

FAST hopes to find particularly weird pulsar specimens, ones that spin at sub-millisecond speeds or orbit near black holes as a binary pair.

Peng also said that the FAST team were using the radio telescope to find out how clumps of cold gas, a source of fuel for star formation, was distributed in the Milky Way. It also contributes to the SETI Institute by looking out for rogue signals from possible alien civilisations.

The telescope, made up of 4,450 reflecting panels, covers a range of radio frequencies between 70MHz to 3GHz. ®

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From Sky & Telescope: “Astronomers Pinpoint New Fast Radio Burst”

From Sky & Telescope

June 27, 2019
Monica Young

A next-gen Australian radio array has enabled astronomers to home in on the source of a mysterious fast radio burst — and the source is not what they expected.

The galaxy from which the burst originated was imaged by three of the world’s largest optical telescopes – Keck, Gemini South and the European Southern Observatory’s Very Large Telescope. The image combined with radio data shows that FRB 180924 lies on the outskirts of a massive “dead” galaxy.
CSIRO / Sam Moorfield

Keck Observatory, operated by Caltech and the University of California, Maunakea Hawaii USA, 4,207 m (13,802 ft)

Gemini/South telescope, Cerro Tololo Inter-American Observatory (CTIO) campus near La Serena, Chile, at an altitude of 7200 feet

ESO VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
•KUEYEN (UT2; The Moon ),
•MELIPAL (UT3; The Southern Cross ), and
•YEPUN (UT4; Venus – as evening star).
elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo,

If you could “listen” to the whole radio sky at once, you’d mostly hear a faint background hiss, like the static between radio stations. But roughly every 10 seconds, you’d pick up a downslurred whistle reminiscent of the Northern Cardinal’s song. This bright sound comes from so-called fast radio bursts (FRBs). Each one lasts only a small fraction of a second (hence “fast”), but in that time it carries some 10,000 times the energy of the Sun.

Since their discovery in 2007, FRBs have maintained an air of mystery. Astronomers have spotted 76 of the fleet emissions so far (and counting), but theories about their origins abound in part because they’re difficult to pin down. Until now, astronomers have only been able to localize one emission, FRB 121102, and that was only because it repeated often enough that astronomers could home in on its origin.

Now, Keith Bannister (CSIRO) and colleagues have used the 36-dish Australian Square Kilometer Array Pathfinder (ASKAP) to pinpoint the source of another FRB — one that doesn’t repeat. The feat, published on June 27th in Science, offers another avenue to understanding these puzzling sources.

Australian Square Kilometre Array Pathfinder (ASKAP) is a radio telescope array located at Murchison Radio-astronomy Observatory (MRO) in the Australian Mid West. ASKAP consists of 36 identical parabolic antennas, each 12 metres in diameter, working together as a single instrument with a total collecting area of approximately 4,000 square metres.

One of These Is Not Like the Other

When ASKAP captured the signal known as FRB 180924, an automated search pipeline triggered the receivers to save everything about the event. That information enabled ASKAP to not only detect the event, it also recorded enough information to pinpoint its source to within 0.12 arcsecond, in a massive galaxy whose light has traveled for 3.6 billion years to reach Earth.

Bannister’s team followed up with sensitive observations of the galaxy and its surroundings using the Very Large Telescope and the Gemini South Telescope in Chile and the Keck II Telescope in Hawai‘i. Images show the galaxy is a cross between an elliptical and a spiral. If it has any spiral arms around its big bulge, they’re tightly wound and difficult to see. Spectroscopic measurements show little to no evidence of star formation. If the burst really belongs to this galaxy, it’s in its anemic outer reaches.

This finding is in stark contrast to the home of the repeating burst FRB 121102. It appears to originate from within a radio-emitting nebula that’s part of a dwarf galaxy that’s birthing stars at a high rate. Given the plethora of new stars, astronomers think FRB 121102 is likely a highly magnetized kind of newborn neutron star known as a magnetar.

A composite image of the field around the first repeating fast radio burst, FRB 121102 (indicated), showed that the burst came from a star-forming dwarf galaxy.
Gemini Observatory / AURA / NSF / NRC

FRBs are known for having large dispersion measures, which means that the lower frequencies arrive much later than the higher-frequency ones. That’s what gives them the “sound” of a cardinal-like downslurred whistle. The longer-frequency photons are delayed by interacting with electrons, and in the case of FRB 121102, the whistle was so extended, it indicated that not only had the pulse traveled a long way, but that the source itself was probably embedded in highly magnetized plasma, which supports the magnetar scenario.

But are all FRBs magnetars? Astronomers have already been saying that even if the scenario pans out for FRB 121102, it might not explain FRBs as a population. The vast majority of these events, after all, don’t repeat.

“Basing models entirely on [FRB 121102’s] properties is dangerous, since the FRB population could be made up of different classes of sources,” says Victoria Kaspi (McGill University, Canada). Indeed, Bannister and colleagues’ localization of FRB 180924 in a galaxy that has retired from star formation suggests that this source has nothing to do with newborn stars, magnetars or otherwise.

“We now know that some FRBs originate from environments very different from that of FRB 121102,” says Kaspi, who was not involved in the study. “That is a very important finding!”

There’s another aspect of FRB 180924 that’s also telling: its dispersion measure. The distance to the source’s galaxy completely explains the dispersion measure so, unlike the repeater, this source doesn’t seem to be embedded in a highly magnetic plasma.

“If they are all like 121102 then yes, we’d expect the source itself to contribute [to the dispersion measure],” Kaspi notes. “But clearly, they are not all like FRB 121102!”

This single burst is likely the first of many that ASKAP will pinpoint, and other telescopes are working on that ability, too. The Canadian Hydrogen Intensity Mapping Experiment (CHIME) array, for example, could localize sources if it had outrigger telescopes, like “mini-CHIMES,” to provide additional information.

CHIME Canadian Hydrogen Intensity Mapping Experiment -A partnership between the University of British Columbia, the University of Toronto, McGill University, Yale and the National Research Council in British Columbia, at the Dominion Radio Astrophysical Observatory in Penticton, British Columbia, CA Altitude 545 m (1,788 ft)

That would be a boon for an instrument that’s already finding FRBs by the dozen. “Indeed we are planning CHIME outrigger telescopes right now,” Kaspi says.

For now, FRBs retain their mystery, but it’s only a matter of time before we unveil what unique physics is producing these events.

See the full article here .

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Sky & Telescope magazine, founded in 1941 by Charles A. Federer Jr. and Helen Spence Federer, has the largest, most experienced staff of any astronomy magazine in the world. Its editors are virtually all amateur or professional astronomers, and every one has built a telescope, written a book, done original research, developed a new product, or otherwise distinguished him or herself.

Sky & Telescope magazine, now in its eighth decade, came about because of some happy accidents. Its earliest known ancestor was a four-page bulletin called The Amateur Astronomer, which was begun in 1929 by the Amateur Astronomers Association in New York City. Then, in 1935, the American Museum of Natural History opened its Hayden Planetarium and began to issue a monthly bulletin that became a full-size magazine called The Sky within a year. Under the editorship of Hans Christian Adamson, The Sky featured large illustrations and articles from astronomers all over the globe. It immediately absorbed The Amateur Astronomer.

Despite initial success, by 1939 the planetarium found itself unable to continue financial support of The Sky. Charles A. Federer, who would become the dominant force behind Sky & Telescope, was then working as a lecturer at the planetarium. He was asked to take over publishing The Sky. Federer agreed and started an independent publishing corporation in New York.

“Our first issue came out in January 1940,” he noted. “We dropped from 32 to 24 pages, used cheaper quality paper…but editorially we further defined the departments and tried to squeeze as much information as possible between the covers.” Federer was The Sky’s editor, and his wife, Helen, served as managing editor. In that January 1940 issue, they stated their goal: “We shall try to make the magazine meet the needs of amateur astronomy, so that amateur astronomers will come to regard it as essential to their pursuit, and professionals to consider it a worthwhile medium in which to bring their work before the public.”

From ALMA: “Planetary Rings of Uranus Glow in Cold Light”

ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

From ALMA

20 June, 2019

Nicolás Lira
Education and Public Outreach Coordinator
Joint ALMA Observatory, Santiago – Chile
Phone: +56 2 2467 6519
Cell phone: +56 9 9445 7726
Email: nicolas.lira@alma.cl

Masaaki Hiramatsu
Education and Public Outreach Officer, NAOJ Chile
Observatory
, Tokyo – Japan
Phone: +81 422 34 3630
Email: hiramatsu.masaaki@nao.ac.jp

Calum Turner
ESO Assistant Public Information Officer
Garching bei München, Germany
Phone: +49 89 3200 6670
Email: calum.turner@eso.org

Charles E. Blue
Public Information Officer
National Radio Astronomy Observatory Charlottesville, Virginia – USA
Phone: +1 434 296 0314
Cell phone: +1 202 236 6324
Email: cblue@nrao.edu

Artist impression of the planet Uranus and its dark ring system. Rather than observing the reflected sunlight from these rings, astronomers have imaged the millimeter and mid-infrared “glow” naturally emitted by the frigidly cold particles of the rings themselves. Credit: NRAO/AUI/NSF; S. Dagnello

Using the Atacama Large Millimeter/submillimeter Array (ALMA) and the Very Large Telescope (VLT), astronomers have imaged the cold, rock-strewn rings encircling the planet Uranus. Rather than observing the reflected sunlight from these rings, ALMA and the VLT imaged the millimeter and mid-infrared glow naturally emitted by the frigidly cold particles of the rings themselves. Only discovered in 1977, Uranus rings are invisible to most but the largest telescopes. However, they are surprisingly bright in the thermal images from ALMA and VLT.

ESO VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
•KUEYEN (UT2; The Moon ),
•MELIPAL (UT3; The Southern Cross ), and
•YEPUN (UT4; Venus – as evening star).
elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo,

The thermal glow gives astronomers another window onto the rings, which only have been seen because they reflect a little light from the Sun. The new images taken by ALMA and the VLT allowed the team for the first time to measure the temperature of the rings: a cool 77º Kelvin, or 77º degrees above absolute zero; equivalent to -196.15º Celsius.

The observations also confirm that Epsilon, Uranus’s brightest and densest ring, differs from the other known rings within our solar system, in particular, the spectacularly beautiful rings of Saturn, that “are broad, bright and have a range of particle sizes, from micron-sized dust in the innermost D ring to tens of meters in size in the main rings,” said Imke de Pater, a UC Berkeley professor of astronomy. “The small end is missing in the main rings of Uranus; the brightest ring, epsilon, is composed of golf ball-sized and larger rocks.”

By comparison, Jupiter’s rings contain mostly small, micron-sized particles (a micron is a thousandth of a millimeter). Neptune’s rings are also mostly dust, and even Uranus has broadsheets of dust between its narrow main rings.

“We already know that the Epsilon ring is a bit weird because we don’t see the smaller stuff,” said Edward Molter, a graduate student from the same university. “Something has been sweeping the smaller stuff out, or it’s all glomming together. We just don’t know. This is a step to further understanding their composition and whether all of the rings came from the same source material or are different for each one.”

Rings could be former asteroids captured by the planet’s gravity, remnants of moons that crashed into one another and shattered, the remains of moons torn apart when they got too close to Uranus, or debris remaining from the formation 4.5 billion years ago.

The new data was published this week in The Astronomical Journal. De Pater and Molter led the ALMA observations, while Michael Roman and Leigh Fletcher from the University of Leicester, U.K., led the VLT observations.

“The rings of Uranus are compositionally different from Saturn’s main ring, in the sense that in optical and infrared, the albedo, thus the reflectance capacity, is much lower: they are really dark, like charcoal,” Molter said. “They are also extremely narrow compared to the rings of Saturn. The widest of them, Epsilon, varies from 20 to 100 kilometers wide, whereas Saturn’s are hundreds or tens of thousands of kilometers wide.”

The lack of dust-sized particles in Uranus’s main rings was first noted when Voyager 2 flew by the planet in 1986, however, the spacecraft was unable to measure the temperature of the rings. To date, astronomers have counted a total of 13 rings around the planet, with some bands of dust between the rings.

“It’s cool that we can even do this with the instruments we have,” Molter said. “I was just trying to image the planet as best I could, and I saw the rings. It was amazing.”

Both the VLT and ALMA observations were designed to explore the temperature structure of Uranus’ atmosphere, with VLT probing shorter wavelengths than ALMA.

“We were astonished to see the rings jump out clearly when we reduced the data for the first time,” Fletcher said.

This presents an exciting opportunity for the upcoming James Webb Space Telescope, which will be able to provide vastly improved details on the Uranian rings once launched in the coming decade.

The research team was composed by Edward M. Molter [1], Imke de Pater [1], Michael T. Roman [2], and Leigh N. Fletcher [2].

[1] Astronomy Department, University of California, Berkeley; Berkeley CA, 94720, USA.
[2] Department of Physics & Astronomy, University of Leicester, University Road, Leicester, LE1 7RH, UK.

Composite image of Uranus’s atmosphere and rings at radio wavelengths, taken with the Atacama Large Millimeter/submillimeter Array (ALMA) in December 2017. The image shows thermal emission, or heat, from the rings of Uranus for the first time, enabling scientists to determine their temperature is a frigid 77 K (-320 F). Dark bands in Uranus’s atmosphere at these wavelengths show the presence of radiolight-absorbing molecules, in particular hydrogen sulfide (H2S) gas, whereas bright regions like the north polar spot contain very few of these molecules. Credit: ALMA (ESO/NAOJ/NRAO); E. Molter and I. de Pater.

See the full article here .

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Please help promote STEM in your local schools.

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The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA is funded in Europe by the European Organization for Astronomical Research in the Southern Hemisphere (ESO), in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and in East Asia by the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Academia Sinica (AS) in Taiwan.

ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI) and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

From ALMA: “ALMA Finds Earliest Example of Merging Galaxies”

ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

From ALMA

Nicolás Lira
Education and Public Outreach Coordinator
Joint ALMA Observatory, Santiago – Chile
Phone: +56 2 2467 6519
Cell phone: +56 9 9445 7726
Email: nicolas.lira@alma.cl

Masaaki Hiramatsu
Education and Public Outreach Officer, NAOJ Chile
Observatory
, Tokyo – Japan
Phone: +81 422 34 3630
Email: hiramatsu.masaaki@nao.ac.jp

Calum Turner
ESO Assistant Public Information Officer
Garching bei München, Germany
Phone: +49 89 3200 6670
Email: calum.turner@eso.org

Charles E. Blue
Public Information Officer
National Radio Astronomy Observatory Charlottesville, Virginia – USA
Phone: +1 434 296 0314
Cell phone: +1 202 236 6324
Email: cblue@nrao.edu

17 June, 2019

Composite image of B14-65666 showing the distributions of dust (red), oxygen (green), and carbon (blue), observed by ALMA and stars (white) observed by the Hubble Space Telescope. Credit: ALMA (ESO/NAOJ/NRAO), NASA/ESA Hubble Space Telescope, Hashimoto et al.

Researchers using the Atacama Large Millimeter/submillimeter Array (ALMA) observed the earliest combined signals of oxygen, carbon, and dust from a galaxy in the Universe, 13 billion years ago. By comparing the different signals, the team determined that the galaxy is, in fact, two merging galaxies, making it the earliest example of merging galaxies yet discovered.

Takuya Hashimoto at Waseda University, Japan, and his team used ALMA to observe B14-65666, an object located 13 billion light-years away in the constellation Sextans. Because of the finite speed of light, the signals we receive from B14-65666 today had to travel for 13 billion years to reach us. In other words, they show us the image of what the galaxy looked like 13 billion years ago, less than 1 billion years after the Big Bang.

ALMA achieved the earliest observation of radio emissions from oxygen, carbon, and dust in B14-65666. The detection of multiple signals allows astronomers to retrieve complementary information.

Data analysis showed that the emissions are divided into two blobs. Previous observations with the Hubble Space Telescope (HST) had revealed two-star clusters in B14-65666. Now, with the three emission signals detected by ALMA, the team was able to show that the two blobs do in-fact form a single system, but with different speeds; which indicates that the blobs are two merging galaxies. The earliest known example of merging galaxies. The research team estimated that the total stellar mass of B14-65666 is less than 10% that of the Milky Way, meaning that it’s in its earliest phases of evolution. Despite its youth, B14-65666 is producing stars 100 times more actively than the Milky Way. Such active star-formation rate is another signature of galactic mergers because the gas compression in colliding galaxies naturally leads to bursty star-formation.

“With rich data from ALMA and HST, combined with advanced data analysis, we could put the pieces together to show that B14-65666 is a pair of merging galaxies in the earliest era of the Universe,” explains Hashimoto. “Detection of radio waves from three components in such a distant object demonstrates ALMA’s high capability to investigate the distant Universe.”

Present galaxies like our Milky Way have experienced countless, often violent, mergers. Sometimes a more massive galaxy swallowed a smaller one. In rare cases, galaxies with similar sizes merged to form a new, larger galaxy. Mergers are essential for galaxy evolution, attracting many astronomers eager to trace back them.

“Our next step is to search for nitrogen, another major chemical element, and even the carbon monoxide molecule,” said Akio Inoue, a professor at Waseda University. “Ultimately, we hope to observationally understand the circulation and accumulation of elements and material in the context of galaxy formation and evolution.”

These observation results were published as T. Hashimoto et al. “’Big Three Dragons’: a z = 7.15 Lyman Break Galaxy Detected in [OIII] 88 um, [CII] 158 um, and Dust Continuum with ALMA” in the Publications of the Astronomical Society of Japan on June 18, 2019.

The research team members are: Takuya Hashimoto (Waseda University/Osaka Sangyo University/National Astronomical Observatory of Japan), Akio Inoue (Waseda University/Osaka Sangyo University), Ken Mawatari (Osaka Sangyo University/The University of Tokyo), Yoichi Tamura (Nagoya University), Hiroshi Matsuo (National Astronomical Observatory of Japan/SOKENDAI), Hisanori Furusawa (National Astronomical Observatory of Japan), Yuichi Harikane (The University of Tokyo), Takatoshi Shibuya (Kitami Institute of Technology), Kirsten K. Knudsen (Chalmers University of Technology), Kotaro Kohno (The University of Tokyo), Yoshiaki Ono (The University of Tokyo), Erik Zackrisson (Uppsala University), Takashi Okamoto (Hokkaido University), Nobunari Kashikawa (National Astronomical Observatory of Japan/SOKENDAI/ The University of Tokyo), Pascal A. Oesch (University of Geneva), Masami Ouchi (The University of Tokyo/National Astronomical Observatory of Japan), Kazuaki Ota (Kyoto University), Ikkoh Shimizu (Osaka University), Yoshiaki Taniguchi (The Open University of Japan), Hideki Umehata (The Open University of Japan/RIKEN), Darach Watson (University of Copenhagen).

See the full article here .

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Please help promote STEM in your local schools.

Stem Education Coalition

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA is funded in Europe by the European Organization for Astronomical Research in the Southern Hemisphere (ESO), in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and in East Asia by the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Academia Sinica (AS) in Taiwan.

ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI) and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

From Science Alert: “Astronomers Find First Evidence of an Odd Radio ‘Bridge’ Connecting 2 Galaxy Clusters”

From Science Alert

7 JUN 2019
MICHELLE STARR

(M. Murgia/INAF)

A colossal magnetic field stretching between two clusters of galaxies has been observed for the first time. Roughly a billion light-years away, the ‘bridge’ of radio-emitting plasma spans 10 million light-years, following a filament in the mysterious cosmic web that connects the Universe.

The space between clusters of galaxies isn’t completely dark and empty. Long strands of diffuse and tenuous gas and plasma stretch between them; these are called filaments, the entire network of which constitutes the cosmic web.

Cosmic web Millenium Simulation Max Planck Institute for Astrophysics

But they’re very difficult to study, as faint as they are in a Universe teeming with bright things.

Previous observations with ground-based radio telescopes had shown ‘haloes’ of radio emission indicating the presence of a magnetic field in the central region of some clusters – some of which contain thousands of galaxies – but no one had ever seen a magnetic field connecting one cluster to another.

So the discovery of a magnetic field in the filament between merging clusters Abell 0399 and Abell 0401 is something extraordinary.

“Our group had discovered that both clusters have a radio halo. More recently, the Planck satellite has shown that the two systems are connected by a thin filament of matter,” said astronomer Federica Govoni of the National Institute for Astrophysics in Italy (INAF).

ESA/Planck 2009 to 2013

“The presence of this filament stimulated our curiosity and prompted us to investigate whether the magnetic field could extend beyond the center of the clusters, permeating the filament of matter that connects them.”

Using the low-frequency radio telescope LoFar, which consists of 25,000 antennas across 51 locations, the team homed in on the filament, detecting a ‘ridge’ of low-frequency radio emission extending between them.

ASTRON LOFAR Radio Antenna Bank, Netherlands

(M. Murgia/INAF)

This is synchrotron radiation produced by electrons zipping along the filament at relativistic velocities, only possible if the magnetic field is acting as a synchrotron, or particle accelerator.

“We typically observe this emission mechanism in action in individual galaxies and even in galaxy clusters, but never before has a radio emission been observed connecting two of these systems,” said INAF astronomer Matteo Murgia.

But there is a slight hiccup: the electrons are covering way more distance than is expected – which means there has to be another element at play. And that element could be the clusters themselves.

Even though they’re separated by a distance of millions of light-years, Abell 0399 and Abell 0401 are creating a great deal of gravitational disturbance in the space around them as they draw inexorably closer together.

The team ran computer simulations to see if any of the dynamics of this merger could be influencing the acceleration of the electrons. Lo and behold, they found an answer. In the simulations, shock waves generated by the merger re-accelerated high-speed electrons, resulting in an emission consistent with the LoFar observations.

But that’s just one potential mechanism. We won’t know for sure until more observations are made.

We also don’t know if other filaments also contain magnetic fields, or if it’s a property unique to Abell 0399 and 0401, or if it’s only found in merging galaxies.

We don’t know where the pre-existing relativistic electrons came from – their velocity implies an energetic origin that could have ejected them at speed, such as supernovae. Nor do we know how prevalent these pre-existing relativistic electrons are in the cosmic web.

If their origin is something common, such as supernovae, there could be more of them around than we could have ever guessed.

It’s certainly given scientists a lot to think about. Not to mention how awesome it is to see scientists following a hunch, and having it pay off.

“With great satisfaction,” Govoni said, “the image obtained with the LoFar radio telescope confirmed our intuition, showing what can be defined as a sort of ‘aurora’ on cosmic scales.”

The research has been published in Science.

See the full article here .

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Please help promote STEM in your local schools.

Stem Education Coalition

From ALMA: “Cool, Nebulous Ring around Milky Way’s Supermassive Black Hole”

ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

From ALMA

5 June, 2019
Nicolás Lira
Education and Public Outreach Coordinator
Joint ALMA Observatory, Santiago – Chile
Phone: +56 2 2467 6519
Cell phone: +56 9 9445 7726
Email: nicolas.lira@alma.cl

Masaaki Hiramatsu
Education and Public Outreach Officer, NAOJ Chile
Observatory
, Tokyo – Japan
Phone: +81 422 34 3630
Email: hiramatsu.masaaki@nao.ac.jp

Calum Turner
ESO Assistant Public Information Officer
Garching bei München, Germany
Phone: +49 89 3200 6670
Email: calum.turner@eso.org

Charles E. Blue
Public Information Officer
National Radio Astronomy Observatory Charlottesville, Virginia – USA
Phone: +1 434 296 0314
Cell phone: +1 202 236 6324
Email: cblue@nrao.edu

Artist impression of ring of cool, interstellar gas surrounding the supermassive black hole at the center of the Milky Way. New ALMA observations reveal this structure for the first time. Credit: NRAO/AUI/NSF; S. Dagnello

ALMA image of the disk of cool hydrogen gas flowing around the supermassive black hole at the center of our galaxy. The colors represent the motion of the gas relative to Earth: the red portion is moving away, so the radio waves detected by ALMA are slightly stretched, or shifted, to the “redder” portion of the spectrum; the blue color represents gas moving toward Earth, so the radio waves are slightly scrunched, or shifted, to the “bluer” portion of the spectrum. Credit: ALMA (ESO/NAOJ/NRAO), E.M. Murchikova; NRAO/AUI/NSF, S. Dagnello

New ALMA observations reveal a never-before-seen disk of cold, interstellar gas wrapped around the supermassive black hole at the center of the Milky Way. This nebulous disk gives astronomers new insights into the workings of accretion: the siphoning of material onto the surface of a black hole. The results are published in the journal Nature.

Through decades of study, astronomers have developed a clearer picture of the chaotic and crowded neighborhood surrounding the supermassive black hole at the center of the Milky Way. Our galactic center is approximately 26,000 light-years from Earth and the supermassive black hole there, known as Sagittarius A* (A “star”), is 4 million times the mass of our Sun.

SgrA* NASA/Chandra supermassive black hole at the center of the Milky Way

SO-2 and SO-38 circle SGR A*Image UCLA Galactic Center Groupe via S. Sakai and Andrea Ghez at Keck Observatory

We now know that this region is brimming with roving stars, interstellar dust clouds, and a large reservoir of both phenomenally hot and comparatively colder gases. These gasesare expected toorbit the black hole in a vast accretion disk that extends a few tenths of a light-year from the black hole’s event horizon.

Until now, however, astronomers have only been able to image the tenuous, hot portion of this accreting gas, which forms a roughly spherical flow and showed no obvious rotation. Its temperature is estimated to be a blistering 10 million degrees Celsius (18 million degrees Fahrenheit), or about halfthe temperature found at the core of our Sun. At this temperature, the gas glows fiercely in X-ray light, allowing it to be studied by space-based X-ray telescopes, down to scale of about a tenth of a light-year from the black hole.

In addition to this hot, glowing gas, previous observations with millimeter-wavelength telescopes have detected a vast store of comparatively cooler hydrogen gas (nearly10 thousand degrees Celsius or 18,000 degrees Fahrenheit) within few light years around the black hole. The contributionof this cooler gas to the accretion flow onto the back hole was previously unknown.

Although our galactic center black hole is relatively quiet,the radiation around it is strongenough to cause hydrogen atoms to continually lose and recombine with their electrons. This recombination produces a distinctive millimeter-wavelength signal, which is capable of reaching the Earth with very little losses on the way.With its remarkable sensitivity and powerful ability to see fine details, the Atacama Large Millimeter/submillimeter Array (ALMA)was able to detect this faint radio signal and produce the first-ever image of the cooler gas disk surrounding the Milky Way’s supermassive black hole at only about a hundredth of a light-year away, or about 1000 times the distance from the Earth to the Sun.These observations enabled the astronomers both to map the location and trace the motion of this gas.The researchers estimate that the amount of hydrogen in this cool disk is about one tenth the mass of Jupiter, or one ten-thousandth of the mass of the Sun.

By mapping the shifts in wavelengths of this radio light due to the Doppler effect (light from objects moving toward the Earth is slightly shifted to the “bluer” portion of the spectrum while light from objects moving away is slightly shifted to the “redder” portion), the astronomers could clearly see that the gas is rotatingaround the black hole. This information will provide new insights into the ways that black holes devour matter and the complex interplay between a black hole and its galactic neighborhood.

“We were the first to image this elusive disk and study its rotation,” said Elena Murchikova, a member in astrophysics at the Institute for Advanced Study in Princeton, New Jersey.“We are also probing accretion onto the black hole. This is important because this is our closest supermassive black hole. Even so, we still have no good understanding of how its accretion works. We hope these new ALMA observations will help the black hole give up some of its secrets.”

See the full article here .

five-ways-keep-your-child-safe-school-shootings

Please help promote STEM in your local schools.

Stem Education Coalition

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA is funded in Europe by the European Organization for Astronomical Research in the Southern Hemisphere (ESO), in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and in East Asia by the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Academia Sinica (AS) in Taiwan.

ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI) and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.