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  • richardmitnick 6:57 am on September 3, 2018 Permalink | Reply
    Tags: Arecibo Observatory, , , , , , , , ,   

    From The Atlantic via WIRED: “China Built the World’s Largest Telescope. Then Came the Tourists” 

    Atlantic Magazine

    The Atlantic Magazine

    via

    Wired logo

    WIRED

    08.26.18
    Sarah Scoles

    Thousands of people moved[?*] to let China build and protect the world’s largest telescope. And then the government drew in orders of magnitude more tourists, potentially undercutting its own science in an attempt to promote it.

    FAST radio telescope, with phase arrays from Australia [https://sciencesprings.wordpress.com/2017/12/18/from-csiroscope-our-top-telescope-tech-travels-fast/] located in the Dawodang depression in Pingtang County, Guizhou Province, south China

    “I hope we go inside this golf ball,” Sabrina Stierwalt joked as she and a group of other radio astronomers approached what did, in fact, appear to be a giant golf ball in the middle of China’s new Pingtang Astronomy Town.

    Stierwalt was a little drunk, a lot full, even more tired. The nighttime scene felt surreal. But then again, even a sober, well-rested person might struggle to make sense of this cosmos-themed, touristy confection of a metropolis.

    On the group’s walk around town that night, they seemed to traverse the ever-expanding universe. Light from a Saturn-shaped lamp crested and receded, its rings locked into support pillars that appeared to make it levitate. Stierwalt stepped onto a sidewalk, and its panels lit up beneath her feet, leaving a trail of lights behind her like the tail of a meteor. Someone had even brought constellations down to Earth, linking together lights in the ground to match the patterns in the sky.

    1
    The tourist town, about 10 miles from the telescope, lights up at night. Credit Intentionally Withheld

    The day before, Stierwalt had traveled from Southern California to Pingtang Astronomy Town for a conference hosted by scientists from the world’s largest telescope. It was a new designation: China’s Five-Hundred-Meter Aperture Spherical Radio Telescope, or FAST, had been completed just a year before, in September 2016. Wandering, tipsy, around this shrine to the stars, the 40 or so other foreign astronomers had come to China to collaborate on the superlative-snatching instrument.

    For now, though, they wouldn’t get to see the telescope itself, nestled in a natural enclosure called a karst depression about 10 miles away. First things first: the golf ball.

    As the group got closer, they saw a red carpet unrolled into the entrance of the giant white orb, guarded by iridescent dragons on an inflatable arch. Inside, they buckled up in rows of molded yellow plastic chairs. The lights dimmed. It was an IMAX movie—a cartoon, with an animated narrator. Not the likeness of a person but … what was it? A soup bowl?

    No, Stierwalt realized. It was a clip-art version of the gargantuan telescope itself. Small cartoon FAST flew around big cartoon FAST, describing the monumental feat of engineering just over yonder: a giant geodesic dome shaped out of 4,450 triangular panels, above which receivers collect radio waves from astronomical objects.

    FAST’s dish, nestled into a depression, is made of thousands of triangular panels. located in the Dawodang depression in Pingtang County, Guizhou Province, south China located in the Dawodang depression in Pingtang County, Guizhou Province, south China VCGGetty Images

    China spent $180 million to create the telescope, which officials have repeatedly said will make the country the global leader in radio astronomy. But the local government also spent several times that on this nearby Astronomy Town—hotels, housing, a vineyard, a museum, a playground, classy restaurants, all those themed light fixtures. The government hopes that promoting their scope in this way will encourage tourists and new residents to gravitate to the historically poor Guizhou province.

    It is, in some sense, an experiment into whether this type of science and economic development can coexist. Which is strange, because normally, they purposefully don’t.

    The point of radio telescopes is to sense radio waves from space—gas clouds, galaxies, quasars. By the time those celestial objects’ emissions reach Earth, they’ve dimmed to near-nothingness, so astronomers build these gigantic dishes to pick up the faint signals. But their size makes them particularly sensitive to all radio waves, including those from cell phones, satellites, radar systems, spark plugs, microwaves, Wi-Fi, short circuits, and basically anything else that uses electricity or communicates. Protection against radio-frequency interference, or RFI, is why scientists put their radio telescopes in remote locations: the mountains of West Virginia, the deserts of Chile, the way-outback of Australia.

    FAST’s site used to be remote like that. The country even forcibly relocated thousands of villagers who lived nearby, so their modern trappings wouldn’t interfere with the new prized instrument.

    But then, paradoxically, the government built—just a few miles from the displaced villagers’ demolished houses—this astronomy town. It also plans to increase the permanent population by hundreds of thousands. That’s a lot of cell phones, each of which persistently emits radio waves with around 1 watt of power.

    By the time certain deep-space emissions reach Earth, their power often comes with 24+ zeroes in front: 0.0000000000000000000000001 watts.

    FAST has been in the making for a long time. In the early 2000s, China angled to host the Square Kilometre Array, a collection of coordinated radio antennas whose dishes would be scattered over thousands of miles. But in 2006, the international SKA committee dismissed China, and then chose to set up its distributed mondo-telescope in South Africa and Australia instead.

    Undeterred, Chinese astronomers set out to build their own powerful instrument.

    In 2007, China’s National Development and Reform Commission allocated $90 million for the project, with $90 million more streaming in from other agencies. Four years later, construction began in one of China’s poorest regions, in the karst hills of the southwestern part of the country. They do things fast in China: The team finished the telescope in just five years. In September 2016, FAST received its “first light,” from a pulsar 1,351 light-years away, during its official opening.

    A year later, Stierwalt and the other visiting scientists arrived in Pingtang, and after an evening of touring Astronomy Town, they got down to business.

    See, FAST’s opening had been more ceremony than science (the commissioning phase is officially scheduled to end by September 2019). It was still far from fully operational—engineers are still trying to perfect, for instance, the motors that push and pull its surface into shape, allowing it to point and focus correctly. And the relatively new crop of radio astronomers running the telescope were hungry for advice about how to run such a massive research instrument.

    The visiting astronomers had worked with telescopes that have contributed to understanding of hydrogen emissions, pulsars, powerful bursts, and distant galaxies. But they weren’t just subject experts: Many were logistical wizards, having worked on multiple instruments and large surveys, and with substantial and dispersed teams. Stierwalt studies interacting dwarf galaxies, and while she’s a staff scientist at Caltech/IPAC, she uses telescopes all over. “Each gives a different piece of the puzzle,” she says. Optical telescopes show the stars. Infrared instruments reveal dust and older stars. X-ray observatories pick out black holes. And single-dish radio telescopes like FAST see the bigger picture: They can map out the gas inside of and surrounding galaxies.

    So at the Radio Astronomy Conference, Stierwalt and the other visitors shared how FAST could benefit from their instruments, and vice versa, and talked about how to run big projects. That work had begun even before the participants arrived. “Prior to the meeting, I traveled extensively all over the world to personally meet with the leaders of previous large surveys,” says Marko Krčo, a research fellow who’s been working for the Chinese Academy of Sciences since the summer of 2016.

    He asked the meeting’s speakers, some of those same leaders, to talk about what had gone wrong in their own surveys, and how the interpersonal end had functioned. “How did you organize yourselves?” he says. “How did you work together? How did you communicate?”

    That kind of feedback would be especially important for FAST to accomplish one of its first, appropriately lofty goals: helping astronomers collect signals from many sides of the universe, all at once. They’d call it the Commensal Radio Astronomy FAST Survey, or CRAFTS.

    3
    Above the dish, engineers have suspended instruments that collect cosmic radio waves. Feature China/Barcroft Media/Getty Images

    Most radio astronomical surveys have a single job: Map gas. Find pulsars. Discover galaxies. They do that by collecting signals in a receiver suspended over the dish of a radio telescope, engineered to capture a certain range of frequencies from the cosmos. Normally, the different astronomer factions don’t use that receiver at the same time, because they each take their data differently. But CRAFTS aims to be the first survey that simultaneously collects data for such a broad spectrum of scientists—without having to pause to reconfigure its single receiver.

    CRAFTS has a receiver that looks for signals from 1.04 gigahertz to 1.45 gigahertz, about 10 times higher than your FM radio. Within that range, as part of CRAFTS, scientists could simultaneously look for gas inside and beyond the galaxy, scan for pulsars, watch for mysterious “fast radio bursts,” make detailed maps, and maybe even search for ET. “That sounds straightforward,” says Stierwalt. “Point the telescope. Collect the data. Mine the data.”

    4
    Engineers from FAST and the Australian science agency install the telescope’s CRAFTS receiver. Marko Krčo

    But it’s not easy. Pulsar astronomers want quicktime samples at a wide range of frequencies; hydrogen studiers, meanwhile, don’t need data chunks as often, but they care deeply about the granular frequency details. On top of that, each group adjusts the observations, calibrating them, kind of like you’d make sure your speedometer reads 45 mph when you’re going 45. And they use different kinds of adjustments.

    When we spoke, Krčo had just returned from a trip to Green Bank, where he was testing whether they could set everyone’s speedometer correctly. “I think it will be one of the big sort of legacies of FAST,” says Krčo. And it’s especially important since the National Science Foundation has recently cratered funding to both Arecibo and Green Bank observatories, the United States’ most significant single-dish radio telescopes.


    NAIC Arecibo Observatory, previously the largest radio telescope in the world operated by University of Central Florida, Yang Enterprises and UMET, Altitude 497 m (1,631 ft)

    Green Bank does have financial support, $2 million per year for five years from Yuri Milner’s Breaktrhough Listen Project.

    Breakthrough Listen Project

    1

    Lick Automated Planet Finder telescope, Mount Hamilton, CA, 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

    While they remain open, they have to seek private project money, meaning chunks of time are no longer available for astronomers’ proposals. Adding hours, on a different continent, helps everybody.

    At the end of the conference in Pingtang County, Krčo and his colleagues presented a concrete plan for CRAFTS, giving all the visitors a chance to approve the proposed design. “Each group could raise any red flags, if necessary, regarding their individual science goals or suggest modifications,” says Krčo.

    In addition to the CRAFTS receiver, Krčo says they’ll add six more, sensitive to different frequencies. Together, they will detect radio waves from 70 megahertz to 3 gigahertz. He says they’ll find thousands of new pulsars (as of July 2018, they had already found more than 40), and do detailed studies of hydrogen inside the galaxy and in the wider universe, among numerous other worthy scientific goals.

    “There’s just a hell of a lot of work to do to get there,” says Krčo. “But we’re doing it.”

    For FAST to fulfill its potential, though, Krčo and his colleagues won’t just have to solve engineering problems: They’ll also have to deal with the problems that engineering created.

    During the four-day Radio Astronomy Forum, Stierwalt and the other astronomers did, finally, get to see the actual telescope, taking a bus up a tight, tortuous road through the karst between town and telescope.

    As soon as they arrived on site, they were instructed to shut down their phones to protect the instrument from the radio frequency interference. But not even these astronomers, who want pristine FAST data for themselves, could resist pressing that capture button. “Our sweet, sweet tour guide continually reminded us to please turn off our phones,” says Stierwalt, “but we all kept taking pictures and sneaking them out because no one really seemed to care.” Come on: It’s the world’s largest telescope.

    Maybe their minder stayed lax because a burst here or there wouldn’t make much of a difference in those early days. The number of regular tourists allowed at the site all day is capped at 3,000, to limit RFI, and they have to put their phones in lockers before they go see the dish. Krčo says the site bumps up against the visitor limit most days.

    But tourism and development are complicated for a sensitive scientific instrument. Within three miles of the telescope, the government passed legislation establishing a “radio-quiet zone,” where RFI-emitting devices are severely restricted. No one (not cellular providers or radio broadcasters) can get a transmitting license, and people entering the facility itself will have their electronics confiscated. “No one lives inside the zone, and the area is not open to the general public,” says Krčo, although some with commercial interests, like local farmers, can enter the zone with special permission. The government relocated villagers who lived within that protected area with promises of repayment in cash, housing, and jobs in tourism and FAST support services. (Though a 2016 report in Agence France-Presse revealed that up to 500 relocated families were suing the Pingtang government, alleging “land grabs without compensation, forced demolitions and unlawful detentions.”)

    The country’s Civil Aviation Administration has also adjusted air travel, setting up two restricted flight zones near the scope, canceling two routes, and adding or adjusting three others. “We can still see some RFI from aircraft navigational beacons,” says Krčo. “It’s much less, though, compared to what it’d look like without the adjusted air routes. It’d be impossible to fully clear a large enough air space to create a completely quiet sky.”

    None of the invisible boundaries, after all, function like force fields. RFI that originates from beyond can pass right on through. At least at the five-star tourist hotel, around 10 miles away, there’s Wi-Fi. The tour center, says an American pulsar astronomer, has a direct line of sight to the telescope.

    When Krčo first arrived on the job, he stayed in the astronomy town. “Every morning, we were counting all the new buildings springing up overnight,” Krčo says. “It would be half a dozen.”

    One day, he woke up to a new five-story structure out his window. Couldn’t be, he thought. But he checked a picture he’d taken the day before, and, sure enough, there had been no building in that spot.

    The corn close to town was covered in construction dust. “I’ve never seen anything like that in my whole life,” says Krčo. Today, though, the corn is gone, covered instead in hotels, museums, and shopping centers.

    5
    Before FAST, few large structures existed in this part of China. Feature China/Barcroft Media/Getty Images

    6
    Now, they abound. Liu Xu/Xinhua/Getty Images

    At a press conference in March 2017, Guizhou’s governor declared that the province would build 10,000 kilometers of new highway by 2020, in addition to completing 17 airports and 4,000 kilometers of high-speed train lines. That’s partly to accommodate the hundreds of thousands of people the province expects to relocate here permanently, as well as the tourists. While just those 3,000 people per day will get to visit the telescope itself, there’s no cap on how many can sojourn in Astronomy Town; the deputy director of Guizhou’s reform and development commission, according to China Daily, said it would be “a main astronomical tourism zone worldwide.” “The town has grown incredibly over the last couple of years due to tourism development,” says Krčo. “This has impacted our RFI environment, but not yet to a point where it is unmanageable.”

    Krčo says that geography protects FAST against much of that human interference. “There are a great many mountains between the telescope and the town,” says Krčo. The land blocks the waves, which you’ve seen yourself if you’ve ever tried to pick up NPR in a canyon. But even though the waves can’t go directly into the telescope, Krčo says the team still sees their echoes, reflections beamed down from the atmosphere.

    “People at the visitors’ center have been using cameras and whatnot, and we can see the RFI from that,” he said last November (enforcement seems to have ramped up since then). “During the daytime,” he adds, “our RFI is much worse than nighttime,” largely due to engineers working onsite (that should improve once commissioning is over). But the tourist traps aren’t run and weren’t developed by FAST staff but by various governmental arms—so FAST, really, has no control over what they do.

    The global radio astronomy community has concerns. “I’m absolutely sure that if people are going to bring their toys, then there’s going to be RFI,” says Carla Beaudet, an RFI engineer at Green Bank Observatory, who spends her career trying to help humans see the radio sky despite themselves. Green Bank itself sits in the middle of a strict radio protection zone with a radius of 10 miles, in which there’s no Wi-Fi or even microwaves.

    There are other ways of dealing with RFI—and Krčo says FAST has a permanent team of engineers dedicated to dealing with interference. One solution, which can pick up the strongest contamination, is a small antenna mounted to one of FAST’s support towers. “The idea is that it will observe the same RFI as the big dish,” says Krčo. “Then, in principle, we can remove the RFI from the data in real time.”

    At other telescopes, astronomers are developing machine-learning algorithms that could identify, extract, and compensate for dirty data. All telescopes, after all, have human contamination, even the ones without malls next door. You can’t stop a communications satellite from passing overhead, or a radar beam from bouncing the wrong way across the mountains. And while you can decide not to build a tourist town in the first place, you probably can’t stop a tidal wave of construction once it’s crested.

    In their free evenings at the Radio Astronomy Forum, Stierwalt and the other astronomers wandered through the development. Across from their luxury hotel, workers were constructing a huge mall. It was just scaffolding then, but sparks flew from tools every night. “So the joke was, ‘I wonder if we’ll be able to go shopping at the mall by the end of our trip,’” says Stierwalt.

    At the end of the conference, Stierwalt rode a bus back to the airport, awed by what she’d seen. The karst hills, dipping and rising out the window, looked like those in Puerto Rico, where she had used the 300-meter Arecibo telescope for weeks at a time during her graduate research.

    When she tried to check in for her flight, she didn’t know where to go, what to do. An agent wrote her passport number down wrong.

    A young Chinese man, an astronomer, saw her struggle and approached her. “I’m on your flight,” he said, “and I’ll make sure you get on it.”

    In line after line, they started talking about other things—life, science. “I was describing the astronomy landscape for me,” she says. Never enough jobs, never enough research money, necessary competition with your friends. “For him, it’s very different.”

    He lives in a country that wants to accrete a community of radio astronomers, not winnow one down. A country that wants to support (and promote) ambitious telescopes, rather than defund the ones it has. China isn’t just trying to build a tourist economy around its telescope—it’s also trying to build a scientific culture around radio astronomy.

    That latter part seems like a safe bet. But the first is still uncertain. So is how the tourist economy will affect—for better or worse—FAST’s scientific payoff. “Much like their CRAFTS survey is trying to make everyone happy—all the different kinds of radio astronomers—this will be a true test of ‘Can you make everyone happy?’” says Stierwalt. “Can you make a prosperous astronomy town right next to a telescope that doesn’t want you to be using your phone or your microwave?”

    Right now, nobody knows. But if the speed of everything else in Guizhou is any indication, we’ll all find out fast.

    [* I had previously read, which I cannot any longer back up, that FAST was built in a fortunately found an empty natural bowl in the land. If anyone can correct me, please do]

    See the full article here .

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  • richardmitnick 2:10 pm on August 15, 2018 Permalink | Reply
    Tags: Arecibo Observatory, , , , , New phased aray system coming by 2022,   

    From Astrobiology Magazine: “Arecibo Observatory to Get $5.8 Million Upgrade to Expand View” 

    Astrobiology Magazine

    From Astrobiology Magazine

    This is great news for this grand old lady.


    NAIC Arecibo Observatory operated by University of Central Florida, Yang Enterprises and UMET, Altitude 497 m (1,631 ft)

    The National Science Foundation has awarded a team of scientists $5.8 million to design and mount a supersensitive antenna at the focal point of the Arecibo Observatory’s 1,000-foot-diameter dish, which is managed by the University of Central Florida. The antenna, called a phased-array feed, will increase the telescope’s observation capabilities 500 percent.

    The team, led by Brigham Young University engineering professors Brian Jeffs and Karl Warnick, includes collaborators at UCF and Cornell University. UCF and its partners have managed the facility since April when the team won a bid from the NSF to run the site.

    “We already have one of the most powerful telescopes on the planet, and with this award we will be able to do even more,” said Francisco Cordova, Arecibo site director and an engineer. “We are very excited with the award to fund the new ALPACA (Advanced Cryogenic L-Band Phased Array Camera for Arecibo) receiver at the Arecibo Observatory. This receiver, which is the next generation of our most-used receiver will be able to increase the survey speed by a factor of five. The receiver will accelerate research in gravitational waves, Fast Radio Bursts, dark matter and pulsar surveys, ensuring that AO continues to be at the forefront of radio astronomy for years to come.”

    Cordova has been working with BYU for months to prepare the NSF proposal. Jeffs and Warnick are considered the world’s foremost experts in phased-array feeds and are familiar with Arecibo. Nine years ago, they installed a gold-plated array of many small antennas at Arecibo that increased the surveying ability of the telescope from one beam of radio waves to seven beams. The new NSF-sponsored phased-array feed will have 166 antennas and will increase the field of view of the telescope to 40 beams, providing much smoother and continuous coverage of the sky than conventional receivers. The new array is scheduled to be installed by 2022.

    “We’re taking the most sensitive radio telescope in the world and opening it up so that it can view a larger part of the sky at one time,” Warnick said. “There’s a lot of things in space you can see with an optical camera, but you can see even more with a radio telescope.”

    One scientific objective of the new feed will be tracking new pulsars — especially millisecond pulsars that help signal the presence of gravity waves. Albert Einstein predicted the existence of gravity waves in 1916, but scientists just detected them a few years ago. Gravitational waves are produced by catastrophic events, such as two colliding black holes, and they cause ripples in the fabric of space-time.

    The phased-array feed will also search for extra-terrestrial intelligence, detect Fast Radio Bursts and conduct surveys to help unravel the mystery of dark matter in the universe.

    “Every galaxy in the universe has an invisible cloud of dark matter around it that we don’t yet understand,” Warnick said. “This will help solve one of the mysteries of the universe.”

    Arecibo, which was built in the 1960s, has been making headlines recently for its contributions to major space science news. It helped confirm gravitational waves and FRBs. Just last month, it was used by a team from Switzerland to confirm some of Einstein’s theories. Scientists from around the world use the facility’s powerful instruments to study everything from pulsars and dark matter to solar weather, and NASA uses it to study asteroids. The upgrade will benefit all the work being done at Arecibo and help scientists understand the cosmos.

    UCF is leading the consortium that includes Universidad Metropolitana in Puerto Rico and Yang Enterprises Inc. based in Oviedo, Florida, in managing the NSF facility. The facility, which was damaged when Hurricane Maria hit Puerto Rico last year, opened quickly after the storm. Emergency repairs that needed immediate attention, such as patching roofs and repairing electrical feeds, have been underway since May after the site received hurricane-relief funding. Additional repairs that will require more time and expertise will be completed as soon as possible.

    See the full article here .


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  • richardmitnick 10:02 am on March 9, 2018 Permalink | Reply
    Tags: , Arecibo Observatory, , , , , , Neutron Stars Discovered on Collision Course,   

    From AAS NOVA via Sky & Telescope: “Neutron Stars Discovered on Collision Course” 

    SKY&Telescope bloc

    Sky & Telescope

    AASNOVA

    AAS NOVA

    March 8, 2018
    Susanna Kohler

    1
    Artist’s illustration of the final stages of a neutron-star merger. Scientists have now caught a binary-neutron-star system about 46 million years before this stage. NASA/Goddard Space Flight Center.

    Got any plans in 46 million years? If not, you should keep an eye out for PSR J1946+2052 around that time — this upcoming merger of two neutron stars promises to be an exciting show!

    Survey Success

    1
    Average profile for PSR J1946+2052 at 1.43 GHz from a 2 hr observation from the Arecibo Observatory. Stovall et al. 2018

    It seems like we just wrote about the dearth of known double-neutron-star systems, and about how new surveys are doing their best to find more of these compact binaries. Observing these systems improves our knowledge of how pairs of evolved stars behave before they eventually spiral in, merge, and emit gravitational waves that detectors like the Laser Interferometer Gravitational-wave Observatory might observe.


    VIRGO Gravitational Wave interferometer, near Pisa, Italy

    Caltech/MIT Advanced aLigo Hanford, WA, USA installation


    Caltech/MIT Advanced aLigo detector installation Livingston, LA, USA

    Cornell SXS, the Simulating eXtreme Spacetimes (SXS) project

    Gravitational waves. Credit: MPI for Gravitational Physics/W.Benger-Zib

    ESA/eLISA the future of gravitational wave research

    1
    Skymap showing how adding Virgo to LIGO helps in reducing the size of the source-likely region in the sky. (Credit: Giuseppe Greco (Virgo Urbino group)

    Today’s study, led by Kevin Stovall (National Radio Astronomy Observatory), goes to show that these surveys are doing a great job so far! Yet another double-neutron-star binary, PSR J1946+2052, has now been discovered as part of the Arecibo L-Band Feed Array pulsar (PALFA) survey. This one is especially unique due to the incredible speed with which these neutron stars orbit each other and their correspondingly (relatively!) short timescale for merger.

    An Extreme Example

    The PALFA survey, conducted with the enormous 305-meter radio dish at Arecibo, has thus far resulted in the discovery of 180 pulsars — including two double-neutron-star systems.

    NAIC/Arecibo Observatory, Puerto Rico, USA, at 497 m (1,631 ft) , built into the landscape at Arecibo, Puerto Rico.
    NOAO/AURA/NSF/H. Schweiker/WIYN

    The most recent discovery by Stovall and collaborators brings that number up to three, for a grand total of 16 binary-neutron-star systems (confirmed and unconfirmed) known to date.

    The newest binary in this collection, PSR J1946+2052, exhibits a pulsar with a 17-millisecond spin period that whips around its compact companion at a terrifying rate: the binary period is just 1.88 hours. Follow-up observations with the Jansky Very Large Array and other telescopes allowed the team to identify the binary’s location to high precision and establish additional parameters of the system.

    PSR J1946+2052 is a system of extremes. The binary’s total mass is found to be ~2.5 solar masses, placing it among the lightest binary-neutron-star systems known. Its orbital period is the shortest we’ve observed, and the two neutron stars are on track to merge in less time than any other known neutron-star binaries: in just 46 million years. When the two stars reach the final stages of their merger, the effects of the pulsar’s rapid spin on the gravitational-wave signal will be the largest of any such system discovered to date.

    More Tests of General Relativity

    What can PSR J1946+2052 do for us? This extreme system will be especially useful as a gravitational laboratory. Continued observations of PSR J1946+2052 will pin down with unprecedented precision parameters like the Einstein delay and the rate of decay of the binary’s orbit due to the emission of gravitational waves, testing the predictions of general relativity to an order of magnitude higher precision than was possible before.

    As we expect there to be thousands of systems like PSR J1946+2052 in our galaxy alone, better understanding this binary — and finding more like it — continue to be important steps toward interpreting compact-object merger observations in the future.

    Citation

    K. Stovall et al 2018 ApJL 854 L22. http://iopscience.iop.org/article/10.3847/2041-8213/aaad06/meta

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    AAS Mission and Vision Statement

    The mission of the American Astronomical Society is to enhance and share humanity’s scientific understanding of the Universe.

    The Society, through its publications, disseminates and archives the results of astronomical research. The Society also communicates and explains our understanding of the universe to the public.
    The Society facilitates and strengthens the interactions among members through professional meetings and other means. The Society supports member divisions representing specialized research and astronomical interests.
    The Society represents the goals of its community of members to the nation and the world. The Society also works with other scientific and educational societies to promote the advancement of science.
    The Society, through its members, trains, mentors and supports the next generation of astronomers. The Society supports and promotes increased participation of historically underrepresented groups in astronomy.
    The Society assists its members to develop their skills in the fields of education and public outreach at all levels. The Society promotes broad interest in astronomy, which enhances science literacy and leads many to careers in science and engineering.

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  • richardmitnick 11:48 am on December 22, 2017 Permalink | Reply
    Tags: Arecibo Observatory, , , , , , Near-Earth asteroid 3200 Phaethon   

    From JPL-Caltech: “Arecibo Radar Returns with Asteroid Phaethon Images” 

    NASA JPL Banner

    JPL-Caltech

    December 22, 2017

    DC Agle
    Jet Propulsion Laboratory, Pasadena, Calif.
    818-393-9011
    agle@jpl.nasa.gov

    Dwayne Brown
    NASA Headquarters, Washington
    202-358-1726
    dwayne.c.brown@nasa.gov

    Suraiya Farukhi
    Universities Space Research Association, Columbia, Maryland
    sfarukhi@usra.edu
    410-740-6224

    1
    These radar images of near-Earth asteroid 3200 Phaethon were generated by astronomers at the National Science Foundation’s Arecibo Observatory on Dec. 17, 2017.

    2
    Near-Earth asteroid 3200 Phaethon.
    Credit: Arecibo Observatory/NASA/NSF

    NAIC/Arecibo Observatory, Puerto Rico, USA, at 497 m (1,631 ft)

    Observations of Phaethon were conducted at Arecibo from Dec.15 through 19, 2017. At time of closest approach on Dec. 16 at 3 p.m. PST (3 p.m. EST, 11 p.m. UTC) the asteroid was about 1.1 million miles (1.8 million kilometers) away, or about 4.6 times the distance from Earth to the moon. The encounter is the closest the object will come to Earth until 2093. Image credit: Arecibo Observatory/NASA/NSF

    After several months of downtime after Hurricane Maria blew through, the Arecibo Observatory Planetary Radar has returned to normal operation, providing the highest-resolution images to date of near-Earth asteroid 3200 Phaethon during its Dec. 16 flyby of Earth. The radar images, which are subtle at the available resolution, reveal the asteroid is spheroidal in shape and has a large concavity at least several hundred meters in extent near the leading edge, and a conspicuous dark, circular feature near one of the poles. Arecibo’s radar images of Phaethon have resolutions as fine as about 250 feet (75 meters) per pixel.

    “These new observations of Phaethon show it may be similar in shape to asteroid Bennu, the target of NASA’s OSIRIS-REx spacecraft, but 10 times larger,” said Patrick Taylor, a Universities Space Research Association (USRA), Columbia, Maryland, scientist and group leader for Planetary Radar at Arecibo Observatory. “The dark feature could be a crater or some other topographic depression that did not reflect the radar beam back at us.”

    NASA OSIRIS-REx Spacecraft

    Radar images obtained by Arecibo indicate Phaethon has a diameter of about 3.6 miles (6 kilometers) — roughly 0.6 miles (1 kilometer) larger than previous estimates. Phaethon is the second largest near-Earth asteroid classified as “Potentially Hazardous.” Near-Earth objects are classified as potentially hazardous asteroids (PHAs), based on their size and how closely their orbits approach Earth.

    “Arecibo is an important global asset, crucial for planetary defense work because of its unique capabilities,” said Joan Schmelz of USRA and deputy director of Arecibo Observatory. “We have been working diligently to get it back up and running since Hurricane Maria devastated Puerto Rico.”

    The Arecibo Observatory has the most powerful astronomical radar system on Earth. On Sept. 20, the telescope suffered minor structural damage when Maria, the strongest hurricane to hit the island since 1928, made landfall. Some days after the storm, the telescope resumed radio astronomy observations, while radar observations, which require high power and diesel fuel for generators at the site, resumed operations in early December after commercial power returned to the observatory.

    Asteroid Phaethon was discovered on Oct. 11, 1983, by NASA’s Infrared Astronomical Satellite (IRAS).

    NASA IRAS spacecraft

    Observations of Phaethon were conducted at Arecibo from Dec. 15 through 19, 2017, using the NASA-funded planetary radar system. At time of closest approach on Dec. 16 at 3 p.m. PST (3 p.m. EST, 11 p.m. UTC) the asteroid was about 1.1 million miles (1.8 million kilometers) away, or about 4.6 times the distance from Earth to the moon. The encounter is the closest the object will come to Earth until 2093.

    Radar has been used to observe hundreds of asteroids. When these small, natural remnants of the formation of our solar system pass relatively close to Earth, deep space radar is a powerful technique for studying their sizes, shapes, rotation, surface features and roughness, and for more precise determination of their orbital path.

    The Arecibo Planetary Radar Program is fully funded by NASA through a grant to Universities Space Research Association (USRA), from the Near-Earth Object Observations program. The Arecibo Observatory is a facility of the National Science Foundation operated under cooperative agreement by SRI International, USRA, and Universidad Metropolitana.

    NASA’s Planetary Defense Coordination Office is responsible for finding, tracking and characterizing potentially hazardous asteroids and comets coming near Earth, issuing warnings about possible impacts, and assisting coordination of U.S. government response planning, should there be an actual impact threat.

    More information about the National Science Foundation’s Arecibo Observatory can be found at:

    http://www.naic.edu

    More information about asteroids and near-Earth objects can be found at:

    https://cneos.jpl.nasa.gov

    https://www.jpl.nasa.gov/asteroidwatch

    For more information about NASA’s Planetary Defense Coordination Office, visit:

    https://www.nasa.gov/planetarydefense

    See the full article here .

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    NASA JPL Campus

    Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge [1], on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

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    NASA image

     
  • richardmitnick 6:51 am on May 27, 2017 Permalink | Reply
    Tags: Arecibo Observatory, , , , , , , , ,   

    From McGill: “Homing in on source of mysterious cosmic radio bursts” 

    McGill University

    McGill University

    4 Jan 2017
    No writer credit found

    1

    Astronomers have pinpointed for the first time the home galaxy of a Fast Radio Burst, moving scientists a step closer to detecting what causes these powerful but fleeting pulses of radio waves. FRBs, which last just a few thousandths of a second, have puzzled astrophysicists since their discovery a decade ago.

    “Now we know that at least one of these FRBs originated within a dwarf galaxy located some three billion light-years beyond our Milky Way galaxy,” said McGill University postdoctoral researcher Shriharsh Tendulkar. He and other astronomers presented the findings today at the meeting of the American Astronomical Society in Grapevine, Texas. Results of the research are also published in the journal Nature and in companion papers in The Astrophysical Journal Letters [Tendulkar, S. P., et al. 2017, ApJL, 834, L7. http://iopscience.iop.org/article/10.3847/2041-8213/834/2/L7%5D and [Marcote, B., et al. 2017, ApJL, 834, L8. http://iopscience.iop.org/article/10.3847/2041-8213/834/2/L8%5D.

    Until now, astronomers hadn’t even been able to determine with certainty whether FRBs come from within our galaxy or beyond. While the exact cause of the high-energy bursts remains unclear, the fact that this particular FRB comes from a distant dwarf galaxy represents “a huge advance in our understanding of these events,” said Shami Chatterjee of Cornell University, another member of the international research team that produced the new results.

    A recurring FRB

    There are now 18 known FRBs. All were detected using single-dish radio telescopes that are unable to narrow down the object’s location with enough precision to allow other observatories to identify its host environment. Unlike all the others, however, one FRB, discovered in November of 2012 at the Arecibo Observatory in Puerto Rico, has recurred numerous times – a pattern first detected in late 2015 by McGill PhD student Paul Scholz.

    NAIC/Arecibo Observatory, Puerto Rico, USA

    The repeating bursts from this object, named FRB 121102 after the date of the initial burst, allowed astronomers to watch for it this year using the National Science Foundation’s (NSF) Karl G. Jansky Very Large Array (VLA), a multi-antenna radio telescope system with the resolving power, or ability to see fine detail, needed to precisely determine the object’s location in the sky.

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

    In 83 hours of observing time over six months in 2016, the VLA detected nine bursts from FRB 121102.

    Using the precise VLA position, Tendulkar and other researchers used the Gemini North telescope in Hawaii to make a visible-light image that identified a faint dwarf galaxy at the location of the bursts. Spectroscopic data from Gemini also enabled the researchers to determine that the dwarf galaxy is more than 3 billion light-years from Earth.

    A humble, unassuming host galaxy

    “The host galaxy for this FRB appears to be a very humble and unassuming dwarf galaxy, which is less than 1% of the mass or our Milky Way galaxy,” Tendulkar says. “That’s surprising. One would generally expect most FRBs to come from large galaxies which have the largest numbers of stars and neutron stars — remnants of massive stars. This dwarf galaxy has fewer stars, but is forming stars at a high rate, which may suggest that FRBs are linked to young neutron stars. There are also two other classes of extreme events — long duration gamma-ray bursts and superluminous supernovae — that frequently occur in dwarf galaxies, as well. This discovery may hint at links between FRBs and those two kinds of events.”

    In addition to detecting the bright bursts from FRB 121102, the VLA observations also revealed an ongoing, persistent source of weaker radio emission in the same region.

    Next, a team of observers used the multiple radio telescopes of the European VLBI Network (EVN), along with the 1,000-foot-diameter William E. Gordon Telescope of the Arecibo Observatory, and the NSF’s Very Long Baseline Array (VLBA) to determine the object’s position with even greater accuracy.

    European VLBI

    “These ultra-high precision observations showed that the bursts and the persistent source must be within 100 light-years of each other,” said Jason Hessels, of the Netherlands Institute for Radio Astronomy and the University of Amsterdam.

    “We think that the bursts and the continuous source are likely to be either the same object or that they are somehow physically associated with each other,” said Benito Marcote, of the Joint Institute for VLBI ERIC, Dwingeloo, Netherlands.

    CHIME could help solve puzzle

    The top candidates, the astronomers suggested, are a young neutron star, possibly a highly-magnetic magnetar, surrounded by either material ejected by a supernova explosion or material ejected by a resulting pulsar, or an active supermassive black hole in the galaxy, with radio emission coming from jets of material emitted from the region surrounding the black hole.

    Now, thanks to new images from the Hubble Space Telescope and the 8.2-metre Subaru Telescope in Hawaii, the McGill researchers and a separate team from Tohoku University in Japan have honed in on the source of FRB 121102 even further – to a giant stellar nursery near the centre of the distant dwarf galaxy.

    NASA/ESA Hubble Telescope


    NAOJ/Subaru Telescope at Mauna Kea Hawaii, USA

    4
    5.25.17 New Scientist.Making signals from afar.John R. Foster/SCIENCE PHOTO LIBRARY

    “The Hubble and Subaru images show that the star-forming complex lies on the small galaxy’s outskirts,” Ken Croswell reports for New Scientist.

    “There is still a lot of work to do to unravel the mystery surrounding FRBs,” says McGill physics professor Victoria Kaspi, a senior member of the international team that conducted the new studies. “But identifying the host galaxy for this repeating FRB marks a big step toward solving the puzzle.”

    The Canadian Hydrogen Intensity Mapping Experiment (CHIME), an interferometric radio telescope in British Columbia, could help answer remaining questions, Kaspi notes. CHIME will survey half the sky each day, potentially enabling it to detect dozens of FRBs per day, she says. “Once we understand the origin of this phenomenon, it could provide us with a new and valuable probe of the Universe.”

    CHIME Canadian Hydrogen Intensity Mapping Experiment A partnership between the University of British Columbia McGill University

    The research was supported in part by the National Research Council of Canada, the Natural Sciences and Engineering Research Council of Canada, the Canadian Institute for Advanced Research, the Lorne Trottier Chair in Astrophysics and Cosmology, the European Research Council, and the National Science Foundation (U.S.).

    See the full article here .

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    All about McGill

    With some 300 buildings, more than 38,500 students and 250,000 living alumni, and a reputation for excellence that reaches around the globe, McGill has carved out a spot among the world’s greatest universities.
    Founded in Montreal, Quebec, in 1821, McGill is a leading Canadian post-secondary institution. It has two campuses, 11 faculties, 11 professional schools, 300 programs of study and some 39,000 students, including more than 9,300 graduate students. McGill attracts students from over 150 countries around the world, its 8,200 international students making up 21 per cent of the student body.

     
  • richardmitnick 11:26 am on May 17, 2017 Permalink | Reply
    Tags: Arecibo Observatory, , , , , , , Maura McLaughlin, , , ,   

    From Physics: Women in STEM – “Q and A: Catching a Gravitational Wave with a Pulsar’s Beam” Maura McLaughlin 

    Physics LogoAbout Physics

    Physics Logo 2

    Physics

    May 12, 2017
    Katherine Wright

    Maura McLaughlin explains how the electromagnetic signals from fast-spinning neutron stars could be used to detect gravitational waves.

    1
    Maura McLaughlin. Greg Ellis/West Virginia University

    Pulsars captivate Maura McLaughlin, a professor at West Virginia University. These highly magnetized neutron stars flash beams of electromagnetic radiation as they spin. And with masses equivalent to that of the Sun, but diameters seventy thousand times smaller, they are—besides black holes—the densest objects in the Universe. Astrophysicists still have many questions about pulsars, ranging from how they emit electromagnetic radiation to why they are so incredibly dense. But it’s exploiting the highly stable, periodic electromagnetic signals of pulsars to study gravitational waves that currently has McLaughlin hooked. In an interview with Physics, she explained where her fascination with pulsars came from, what gravitational-wave sources she hopes to detect, and why she recently visited Washington, D.C., to talk with members of Congress.

    With the 2015 detection of gravitational waves, it’s obviously an exciting time to work in astrophysics. But what initially drew you to the field and to pulsars?

    The astrophysicist Alex Wolszczan. I met him in the early 90s while I was an undergrad at Penn State, and just after he had discovered the first extrasolar planets. These planets were orbiting a pulsar—lots of people don’t know that. I found this pulsar system fascinating and ended up working with Wolszczan one summer as a research assistant. I got to go to Puerto Rico to observe pulsars at the Arecibo Observatory, which is the biggest telescope in the world. The experience was really cool.
    How do researchers detect gravitational waves with pulsars?

    The collaboration that I’m part of—NANOGrav—is searching for changes in the travel time of the pulsar’s radio emission due to the passing of gravitational waves.

    2

    NANOGrave Gravitational waves JPL-Caltech David Champion

    When a gravitational wave passes between us and the pulsar, it stretches and squeezes spacetime, causing the pulse to arrive a bit earlier or later than it would in the absence of the wave. We time the arrival of pulsar signals for years to try to detect these small changes.
    What gravitational-wave-producing events do you expect to detect with pulsars? Could you see the same events as LIGO did?

    LIGO is sensitive to very short time-scale gravitational waves, on the order of milliseconds to seconds, while our experiment is sensitive to very long time-scale gravitational waves, on the order of years. We could never detect gravitational waves from two stellar-mass black holes merging—the time scale of the event is just too short. But we will be able to detect waves from black hole binaries in their inspiralling stage, when they’re still orbiting each other with periods of years. Also, our approach can only detect black holes that are much more massive that those LIGO observed. Our primary targets are supermassive black holes, even more massive than the one at the core of the Milky Way.


    Caltech/MIT Advanced aLigo Hanford, WA, USA installation


    Caltech/MIT Advanced aLigo detector installation Livingston, LA, USA

    Cornell SXS, the Simulating eXtreme Spacetimes (SXS) project


    Gravitational waves. Credit: MPI for Gravitational Physics/W.Benger-Zib

    ESA/eLISA the future of gravitational wave research

    LIGO is basically probing the evolution and end products of stars, whereas our experiment is probing the evolution of galaxies and the cosmos. We’ll be able to look way back in time at the processes by which galaxies formed through mergers.
    The first detection of gravitational waves was front-page news. What impact has it had on your research?

    I, and others in NANOGrav, got lots of condolences after LIGO’s detection, like “oh we’re sorry you weren’t first.” But it’s been good for us. It has really spurred us on to make a detection. And it has made us more optimistic—if it worked for LIGO it should work for us, as our methods are rooted in the same principles. None of us doubted gravitational waves existed, but as far as funding agencies and the public go, LIGO’s detection makes a big difference. Now people can’t say, “Who knows if these things exist?” or “Who knows if these methods work?” LIGO’s detection has shown they do exist and the methods do work.

    Apart from doubters, what other challenges do you face with your pulsar experiment?

    Right now, our most significant challenge is that our radio telescopes are in danger of being shut down. Both Arecibo and the Green Bank Telescope (GBT) in West Virginia are suffering significant funding cuts.

    NAIC/Arecibo Observatory, Puerto Rico, USA



    GBO radio telescope, Green Bank, West Virginia, USA

    Many of our NANOGrav discussions lately are about what we can do to retain access to these telescopes. Losing one of these telescopes would reduce our experiment’s sensitivity by roughly half and increase the time to detection by at least several years. If we lose both, our project is dead in the water. Arecibo and GBT are currently the two most sensitive radio telescopes in the world . I think its crazy that they are possibly being shut down.

    [Do not forget FAST-China]

    FAST radio telescope, now operating, located in the Dawodang depression in Pingtang county Guizhou Province, South China

    What are you doing to address the problem?

    I recently spent two days on Capitol Hill in Washington, D.C., talking to senators and House representatives trying to make the case to keep GBT open. Most of the politicians actually agreed it should stay open; it’s just a matter of funding. Science in general just doesn’t have enough funding.

    How do you frame the issues when talking to politicians about science?

    I try really hard to stress the opportunities for training students, the infrastructure, and the number of people who work at these telescopes. The technologies developed at the facilities are cutting edge and can be used for more than studying space. The science is incredibly interesting, but that in itself doesn’t always appeal to everybody.

    With the current administration, arguments of US prominence are also really valuable. China [has built ans is operating] a bigger telescope than Arecibo, and soon we won’t have the largest radio telescope in the world. Right now we are world leaders, but if the US wants to keeps its dominance then these telescopes have to remain open.

    With the challenges you face, what would you say to someone thinking of joining this field?

    Despite uncertainties with the telescopes, the future is bright. Now is a really good time to join the field: we’re going to make a detection any day now.

    See the full article here .

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    Physicists are drowning in a flood of research papers in their own fields and coping with an even larger deluge in other areas of physics. How can an active researcher stay informed about the most important developments in physics? Physics highlights a selection of papers from the Physical Review journals. In consultation with expert scientists, the editors choose these papers for their importance and/or intrinsic interest. To highlight these papers, Physics features three kinds of articles: Viewpoints are commentaries written by active researchers, who are asked to explain the results to physicists in other subfields. Focus stories are written by professional science writers in a journalistic style and are intended to be accessible to students and non-experts. Synopses are brief editor-written summaries. Physics provides a much-needed guide to the best in physics, and we welcome your comments (physics@aps.org).

     
  • richardmitnick 6:12 pm on March 7, 2017 Permalink | Reply
    Tags: Arecibo Observatory, , , , ,   

    From APS: “Gravitational Waves: Hints, Allegations, and Things Left Unsaid” 

    AmericanPhysicalSociety

    American Physical Society

    APS April Meeting 2017

    If the APS April Meeting 2016 was a champagne-soaked celebration for gravitational wave scientists, the 2017 meeting was more like spring training — there was lots of potential, but the real action is yet to come.



    Caltech/MIT Advanced aLigo Hanford, WA, USA installation

    Caltech/MIT Advanced aLigo detector installation Livingston, LA, USA

    The Laser Interferometer Gravitational-Wave Observatory, or LIGO, launched the era of gravitational wave astronomy in February 2016 with the announcement of a collision between two black holes observed in September 2015. “I’m contractually obligated to show the slide [of the original detection] at any LIGO talk for at least another year,” joked Jocelyn Read, a physicist at California State University, Fullerton, during her presentation at this year’s meeting.

    The scientific collaboration that operates the two LIGO detectors netted a second merger between slightly smaller black holes on December 26, 2015. (A third “trigger” showed up in LIGO data on October 12, 2015, but ultimately did not meet the stringent “five-sigma” statistical significance standard that physicists generally insist on.)

    The detectors then went offline in January 2016 for repairs and upgrades. The second observing run began on November 30, but due to weather-related shutdowns and other logistical hurdles, the two detectors had operated simultaneously on only 12 days as of this year’s meeting, which limited the experiment’s statistical power. Collaboration members said they had no new detections to announce.

    Instead, scientists focused on sharpening theoretical estimates of how often various events occur. In particular, they are eager to see collisions involving neutron stars, which lack sufficient mass to collapse all the way to a black hole. Neutron star collisions are thought to be plentiful, but would emit weaker gravitational waves than do mergers of more massive black holes, so the volume of space the LIGO detectors can scan for such events is smaller.

    Even with recent upgrades, failure to detect a neutron star merger during the current observing run would not rule out existing models, said Read. But she added that with future improvements and the long-anticipated addition of Virgo, a LIGO-like detector based in Cascina, Italy, neutron stars should soon come out of hiding.



    VIRGO Gravitational Wave interferometer, near Pisa, Italy [Not yet operational]

    “We’re expecting that with a little more volume and a little more time, we’re going to be starting to make some astrophysically interesting statements.”

    LIGO scientists are also looking for signals from individual pulsars — rapidly rotating neutron stars that are observed on earth as pulses of radio waves. A bump on a pulsar’s surface should produce gravitational waves, but so far, no waves with the right shape have been picked up. This absence puts a limit on the size of any irregularities and on the emission power of gravitational waves from nearby pulsars such as the Crab and Vela pulsars, said Michael Landry, head of the Hanford LIGO observatory, and could soon start putting limits on more distant ones.

    Presenters dropped a few hints of possible excitement to come. LIGO data taken through the end of January produced two short signals that were unusual enough to exceed the experiment’s “false alarm” threshold — signals with shapes and strengths expected to show up once a month or less by chance alone. Both LIGO collaboration members and astronomers at conventional telescopes are investigating the data to determine whether they represent real events.

    For now, potential events will continue to be scrutinized by collaboration members, and released to the public via announcements coming months after initial detection. But LIGO leaders expect to shorten the lag time as detections become more frequent, perhaps eventually putting out monthly updates. “We hope to make it quicker,” said LIGO collaboration spokesperson Gabriela González, a physicist at Louisiana State University in Baton Rouge.

    LIGO is not the only means by which scientists are searching for gravitational waves. Some scientists are using powerful radio telescopes to track signals emanating from dozens of extremely fast-rotating pulsars. A specific pattern of correlations between tiny hiccups in the arrival times of these pulses would be a signature of long-wavelength gravitational waves expected from mergers of distant supermassive black holes.

    Teams in the U.S., Europe, and Australia have monitored pulsars for more than a decade, so far without positive results. But in an invited talk, Laura Sampson of Northwestern University in Evanston, Illinois, coyly announced “hints of some interesting signals.” With 11 years of timing data from 18 pulsars tracked by the Green Bank Telescope in West Virginia and the Arecibo Telescope in Puerto Rico, Sampson and other scientists affiliated with a collaboration called NANOGrav have eked out a result with a statistical significance of around 1.5 to 2 sigma.



    GBO radio telescope, Green Bank, West Virginia, USA


    NAIC/Arecibo Observatory, Puerto Rico, USA

    Data from the Green Bank Telescope in West Virginia and Arecibo Telescope in Puerto Rico help researchers use pulsars to study gravitational waves.

    “It’s the first hint we’ve ever had that there might be a signal in the data,” Sampson said. “Everything we’ve done before was straight-up limits.”

    As NANOGrav continues to gather data, their signal could grow toward the 5-sigma gold standard, or it could vanish. Sampson and her colleagues hope to have an answer in the next year or two. “This is of course very exciting news,” said Gonzalez.

    See the full article here .

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    Physicists are drowning in a flood of research papers in their own fields and coping with an even larger deluge in other areas of physics. How can an active researcher stay informed about the most important developments in physics? Physics highlights a selection of papers from the Physical Review journals. In consultation with expert scientists, the editors choose these papers for their importance and/or intrinsic interest. To highlight these papers, Physics features three kinds of articles: Viewpoints are commentaries written by active researchers, who are asked to explain the results to physicists in other subfields. Focus stories are written by professional science writers in a journalistic style and are intended to be accessible to students and non-experts. Synopses are brief editor-written summaries.

     
  • richardmitnick 1:14 pm on February 15, 2017 Permalink | Reply
    Tags: Arecibo Observatory, , , Comet 45P/Honda-Mrkos-Pajdusakova,   

    From SPACEREF: “Arecibo Observatory Images Comet 45P/Honda-Mrkos-Pajdusakova” 

    SpaceRef

    SpaceRef

    February 15, 2017
    Keith Cowing

    1
    Comet 45P/Honda-Mrkos-Pajdusakova. ©Arecibo Observatory

    NAIC/Arecibo Observatory, Puerto Rico, USA
    NAIC/Arecibo Observatory, Puerto Rico, USA

    Though not visible to the naked eye or even with binoculars, the green-tailed Comet 45P/Honda-Mrkos-Pajdusakova (HMP) did not escape the gaze of the world-renowned Arecibo Observatory.

    Scientists from the University of Arizona’s Lunar and Planetary Laboratory (LPL) and the Universities Space Research Association (USRA) at Arecibo Observatory have been studying the comet with radar to better understand its solid nucleus and the dusty coma that surrounds it.

    “Comets are remnants of the planet forming process and are part of a group of objects made of water ice and rocky material that formed beyond Neptune,” noted Dr. Ellen Howell, scientist at LPL and the leader of the observing campaign at Arecibo. “Studying these objects gives us an idea of how the outer reaches of our solar system formed and evolved over time.”

    Studying the comet with radar not only very precisely determines its orbit, allowing scientists to better predict its location in the future, but also gives a glimpse of the typically unseen part, the comet’s nucleus, which is usually hidden behind the cloud of gas and dust that makes up the its coma and tail.

    “The Arecibo Observatory planetary radar system can pierce through the comet’s coma and allows us to study the surface properties, size, shape, rotation, and geology of the comet nucleus,” said Dr. Patrick Taylor, USRA scientist and Group Lead for Planetary Radar at Arecibo. “We gain roughly the same amount of knowledge from a radar observation as a spacecraft flyby of the same object, but at considerably less cost.”

    In fact, the new radar observations have revealed Comet 45P/HMP to be somewhat larger than previously estimated. The radar images suggest a size of about 1.3 km (0.8 mi) and that it rotates about once every 7.6 hours. “We see complex structures and bright regions on the comet and have been able to investigate the coma with radar,” indicated Cassandra Lejoly, graduate student at the University of Arizona.

    This comet is only the seventh imaged using radar because comets rarely come close enough to the Earth to get such detailed radar images. In fact, though 45P/HMP has an orbital period of about 5.3 years, it rarely passes close to Earth, as it is doing now. Comet 45P is one of a group of comets called Jupiter family comets (JFCs), whose orbits are controlled by Jupiter’s gravity and typically orbit the Sun about every 6 years.

    Comet 45P/HMP, which is passing by Earth at a speed of about 23 km/s (relative to Earth) and a close approach of about 32 Earth-Moon distances, will be observed widely at different wavelengths to characterize the gas and dust emanating from the nucleus that forms the coma. As comets orbit the Sun, the ices sublime from solids to gases and escape the nucleus. The nucleus gradually shrinks and will disappear completely within in less than a million years.

    Radar observations at Arecibo of Comet 45P/HMP began on February 9, 2017, and will continue through February 17, 2017.

    The Arecibo Observatory is a facility of the National Science Foundation operated under cooperative agreement by SRI International in alliance with the Universities Space Research Association and Universidad Metropolitana. The Planetary Radar Program at Arecibo is fully funded by NASA through grants from the Near-Earth Object Observations program and managed by USRA.

    See the full article here.

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    Founded in 1969, under the auspices of the National Academy of Sciences, Universities Space Research Association (USRA) is an independent, nonprofit research corporation which offers an avenue for government and industry to engage the expertise of the academic community together with USRA’s own technical leadership, innovative R&D, operational excellence, management of premier facilities and education programs to advance space- and aeronautics-related sciences and exploration. USRA works across disciplines including biomedicine, planetary science, astrophysics, and engineering and integrates those competencies into applications ranging from fundamental research to facility management and operations to develop and deliver sophisticated, forward-looking solutions to Federal agencies and other government sponsors.

     
  • richardmitnick 3:11 pm on January 18, 2017 Permalink | Reply
    Tags: Arecibo Observatory, , , , , Galaxy Murder Mystery, ,   

    From ICRAR: “Galaxy Murder Mystery” 

    ICRAR Logo
    International Centre for Radio Astronomy Research

    January 17, 2017
    Mr Toby Brown (ICRAR-UWA, Swinburne University of Technology)
    E: toby.brown@icrar.org
    M: +61 6488 7753

    Dr Barbara Catinella (ICRAR-UWA)
    E: barbara.catinella@icrar.org
    Tel: +972 89346511

    Pete Wheeler—Media Contact, ICRAR
    E: pete.wheeler@icrar.org
    M: +61 423 982 018

    1
    This artist’s impression shows the spiral galaxy NGC 4921 based on observations made by the Hubble Space Telescope. Credit: ICRAR, NASA, ESA, the Hubble Heritage Team (STScI/AURA)

    It’s the big astrophysical whodunnit. Across the Universe, galaxies are being killed and the question scientists want answered is, what’s killing them?

    New research published today by a global team of researchers, based at the International Centre for Radio Astronomy Research (ICRAR), seeks to answer that question. The study reveals that a phenomenon called ram-pressure stripping is more prevalent than previously thought, driving gas from galaxies and sending them to an early death by depriving them of the material to make new stars.

    The study of 11,000 galaxies shows their gas—the lifeblood for star formation—is being violently stripped away on a widespread scale throughout the local Universe.

    Toby Brown, leader of the study and PhD candidate at ICRAR and Swinburne University of Technology, said the image we paint as astronomers is that galaxies are embedded in clouds of dark matter that we call dark matter halos.

    Dark matter is the mysterious material that despite being invisible accounts for roughly 27 per cent of our Universe, while ordinary matter makes up just 5 per cent. The remaining 68 per cent is dark energy.

    “During their lifetimes, galaxies can inhabit halos of different sizes, ranging from masses typical of our own Milky Way to halos thousands of times more massive,” Mr Brown said.

    “As galaxies fall through these larger halos, the superheated intergalactic plasma between them removes their gas in a fast-acting process called ram-pressure stripping.

    “You can think of it like a giant cosmic broom that comes through and physically sweeps the gas from the galaxies.”

    Mr Brown said removing the gas from galaxies leaves them unable to form new stars.

    “It dictates the life of the galaxy because the existing stars will cool off and grow old,” he said.

    “If you remove the fuel for star formation then you effectively kill the galaxy and turn it into a dead object.”

    ICRAR researcher Dr Barbara Catinella, co-author of the study, said astronomers already knew ram-pressure stripping affected galaxies in clusters, which are the most massive halos found in the Universe.

    “This paper demonstrates that the same process is operating in much smaller groups of just a few galaxies together with much less dark matter,” said Mr. Brown. “Most galaxies in the Universe live in these groups of between two and a hundred galaxies,” he said.

    “We’ve found this removal of gas by stripping is potentially the dominant way galaxies are quenched by their surrounds, meaning their gas is removed and star formation shuts down.”

    The study was published in the journal Monthly Notices of the Royal Astronomical Society. It used an innovative technique combining the largest optical galaxy survey ever completed—the Sloan Digital Sky Survey—with the largest set of radio observations for atomic gas in galaxies —the Arecibo Legacy Fast ALFA survey.

    SDSS Telescope at Apache Point, NM, USA
    SDSS Telescope at Apache Point, NM, USA
    Universe map Sloan Digital Sky Survey (SDSS) 2dF Galaxy Redshift Survey
    Universe map Sloan Digital Sky Survey (SDSS) 2dF Galaxy Redshift Survey

    NAIC/Arecibo Observatory, Puerto Rico, USA
    NAIC/Arecibo Observatory, Puerto Rico, USA
    3
    The Arecibo Legacy Fast ALFA Survey

    Mr Brown said the other main process by which galaxies run out of gas and die is known as strangulation.

    “Strangulation occurs when the gas is consumed to make stars faster than it’s being replenished, so the galaxy starves to death,” he said.

    “It’s a slow-acting process. On the contrary, what ram-pressure stripping does is bop the galaxy on the head and remove its gas very quickly—of the order of tens of millions of years—and astronomically speaking that’s very fast.”

    See the full article here .

    Please help promote STEM in your local schools.
    STEM Icon

    Stem Education Coalition

    ICRAR is an equal joint venture between Curtin University and The University of Western Australia with funding support from the State Government of Western Australia. The Centre’s headquarters are located at UWA, with research nodes at both UWA and the Curtin Institute for Radio Astronomy (CIRA).
    ICRAR has strong support from the government of Australia and is working closely with industry and the astronomy community, including CSIRO and the Australian Telescope National Facility, iVEC, and the international SKA Project Office (SPO), based in the UK.

    ICRAR is:

    Playing a key role in the international Square Kilometre Array (SKA) project, the world’s biggest ground-based telescope array.

    SKA Square Kilometer Array
    Attracting some of the world’s leading researchers in radio astronomy, who will also contribute to national and international scientific and technical programs for SKA and ASKAP.
    Creating a collaborative environment for scientists and engineers to engage and work with industry to produce studies, prototypes and systems linked to the overall scientific success of the SKA, MWA and ASKAP.

    SKA Murchison Widefield Array
    A Small part of the Murchison Widefield Array

    Enhancing Australia’s position in the international SKA program by contributing to the development process for the SKA in scientific, technological and operational areas.
    Promoting scientific, technical, commercial and educational opportunities through public outreach, educational material, training students and collaborative developments with national and international educational organisations.
    Establishing and maintaining a pool of emerging and top-level scientists and technologists in the disciplines related to radio astronomy through appointments and training.
    Making world-class contributions to SKA science, with emphasis on the signature science themes associated with surveys for neutral hydrogen and variable (transient) radio sources.
    Making world-class contributions to SKA capability with respect to developments in the areas of Data Intensive Science and support for the Murchison Radio-astronomy Observatory.

     
  • richardmitnick 3:21 pm on January 5, 2017 Permalink | Reply
    Tags: Arecibo Observatory, , , , , , ,   

    From USRA: “Arecibo Observatory casts new light on cosmic microwave background observed by WMAP and PLANCK spacecraft” 

    usra-bloc

    USRA

    January 4, 2017
    PR Contact: Suraiya Farukhi
    sfarukhi@usra.edu
    Universities Space Research Association
    410-740-6224 (o)
    443-812-6945 (c)

    Technical Contact: Joan Schmelz
    jschmelz@usra.edu
    Universities Space Research Association
    787-878-2612 x603

    NAIC/Arecibo Observatory, Puerto Rico, USA
    NAIC/Arecibo Observatory, Puerto Rico, USA

    Arecibo Observatory observations of galactic neutral hydrogen structure confirm the discovery of an unexpected contribution to the measurements of the cosmic microwave background observed by the WMAP and Planck spacecraft.

    NASA WMAP satellite
    NASA WMAP satellite

    ESA/Planck
    “ESA/Planck

    An accurate understanding of the foreground (galactic) sources of radiation observed by these two spacecraft is essential for extracting information about the small-scale structure in the cosmic microwave background believed to be indicative of events in the early universe.

    Cosmic Microwave Background WMAP
    Cosmic Microwave Background WMAP

    CMB per ESA/Planck
    CMB per ESA/Planck

    The new source of radiation in the 22 to 100 GHz range observed by WMAP and Planck appears to be emission from cold electrons (known as free-free emission). While cosmologists have corrected for this type of radiation from hot electrons associated with galactic nebulae where the source temperatures are thousands of degrees, the new model requires electron temperatures more like a few 100 K.

    The spectrum of the small-scale features observed by WMAP and Planck in this frequency range is very nearly flat — a finding consistent with the sources being associated with the Big Bang. At first glance it appears that the spectrum expected from the emission by cold galactic electrons, which exist throughout interstellar space, would be far too steep to fit the data. However, if the sources of emission have a small angular size compared with the beam width used in the WMAP and Planck spacecraft, the signals they record would be diluted. The beam widths increase with lower frequency, and the net result of this “beam dilution” is to produce an apparently flat spectrum in the 22 to 100 GHz range.

    “It was the beam dilution that was the key insight,” noted Dr. Gerrit Verschuur, astronomer emeritus at the Arecibo Observatory and lead author on the paper. “Emission from an unresolved source could mimic the flat spectrum observed by WMAP and Planck.”

    The model invoking the emission from cold electrons not only gives the observed flat spectrum usually attributed to cosmic sources but also predicts values for the angular scale and temperature for the emitting volumes. Those predictions can then be compared with observations of galactic structure revealed in the Galactic Arecibo L-Band Feed Array (GALFA) HI survey.

    “The interstellar medium is much more surprising and important than we have given it credit for,” noted Dr. Joshua Peek, an astronomer at the Space Telescope Science Institute and a co-investigator on the GALFA-HI survey. “Arecibo, with its combination of large area and high resolution, remains a spectacular and cutting edge tool for comparing ISM maps to cosmological data sets.”

    The angular scales of the smallest features observed in neutral hydrogen maps made at Arecibo and the temperature of the apparently associated gas both match the model calculations extremely well. So far only three well-studied areas have been analyzed in such detail, but more work is being planned.

    “It was the agreement between the model predictions and the GALFA-HI observations that convinced me that we might be onto something,” noted Dr. Joan Schmelz, Director, Universities Space Research Association (USRA) at Arecibo Observatory and a coauthor on the paper. “We hope that these results help us understand the true cosmological nature of Planck and WMAP data.”

    The data suggest that the structure and physics of diffuse interstellar matter, in particular of cold hydrogen gas and associated electrons, may be more complex than heretofore considered. Such complexities need to be taken into account in order to produce better foreground masks for application to the high-frequency continuum observations of Planck and WMAP in the quest for a cosmologically significant signal.

    USRA’s Dr. Joan Schmelz will present these findings on January 4, 2017, at a press conference at the American Astronomical Society’s (AAS) meeting at Grapevine, Texas.

    The results were published in the Astrophysical Journal, December 1, 2016, in a paper entitled On the Nature of Small-Scale Structure in the Cosmic Microwave Background Observed by Planck and WMAP by G. L. Verschuur and J. T. Schmelz.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    USRA is an independent, nonprofit research corporation where the combined efforts of in-house talent and university-based expertise merge to advance space science and technology.

    SIGNIFICANCE & PURPOSE

    USRA was founded in 1969, near the beginning of the Space Age, driven by the vision of two individuals, James Webb (NASA Administrator 1961-1968) and Frederick Seitz (National Academy of Sciences President 1962-1969). They recognized that the technical challenges of space would require an established research base to develop novel concepts and innovative technologies. Together, they worked to create USRA to satisfy not only the ongoing need for innovation in space, but also the need to involve society more broadly so the benefits of space activities would be realized.

     
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