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  • richardmitnick 6:45 pm on March 19, 2019 Permalink | Reply
    Tags: "Astronomers Find “Cannonball Pulsar” Speeding Through Space", , , , , Dame Susan Jocelyn Bell Burnell, , PSR J0002+6216,   

    From National Radio Astronomy Observatory: “Astronomers Find “Cannonball Pulsar” Speeding Through Space” 


    From National Radio Astronomy Observatory

    NRAO Banner

    March 19, 2019

    Dave Finley, Public Information Officer
    (575) 835-7302
    dfinley@nrao.edu

    Object got powerful “kick” from supernova explosion.

    1
    Credit: Composite by Jayanne English, University of Manitoba; F. Schinzel et al.; NRAO/AUI/NSF; DRAO/Canadian Galactic Plane Survey; and NASA/IRAS.

    Astronomers using the National Science Foundation’s Karl G. Jansky Very Large Array (VLA) [below] have found a pulsar speeding away from its presumed birthplace at nearly 700 miles per second, with its trail pointing directly back at the center of a shell of debris from the supernova explosion that created it. The discovery is providing important insights into how pulsars — superdense neutron stars left over after a massive star explodes — can get a “kick” of speed from the explosion.

    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 2009

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

    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.

    “This pulsar has completely escaped the remnant of debris from the supernova explosion,” said Frank Schinzel, of the National Radio Astronomy Observatory (NRAO). “It’s very rare for a pulsar to get enough of a kick for us to see this,” he added.

    The pulsar, dubbed PSR J0002+6216, about 6,500 light-years from Earth, was discovered in 2017 by a citizen-science project called Einstein@Home, running on BOINC software from UC Berkeley Space Science Center. That project uses computer time donated by volunteers to analyze data from NASA’s Fermi Gamma-ray Space Telescope. So far, using more than 10,000 years of computing time, the project has discovered a total of 23 pulsars.

    einstein@home

    NASA/Fermi Gamma Ray Space Telescope

    Radio observations with the VLA clearly show the pulsar outside the supernova remnant, with a tail of shocked particles and magnetic energy some 13 light-years long behind it. The tail points back toward the center of the supernova remnant.

    “Measuring the pulsar’s motion and tracing it backwards shows that it was born at the center of the remnant, where the supernova explosion occurred,” said Matthew Kerr, of the Naval Research Laboratory. The pulsar now is 53 light-years from the remnant’s center.

    “The explosion debris in the supernova remnant originally expanded faster than the pulsar’s motion,” said Dale Frail, of NRAO. “However, the debris was slowed by its encounter with the tenuous material in interstellar space, so the pulsar was able to catch up and overtake it,” he added.

    The astronomers said that the pulsar apparently caught up with the shell about 5,000 years after the explosion. The system now is seen about 10,000 years after the explosion.

    The pulsar’s speed of nearly 700 miles per second is unusual, the scientists said, with the average pulsar speed only about 150 miles per second. “This pulsar is moving fast enough that it eventually will escape our Milky Way Galaxy,” Frail said.

    Astronomers have long known that pulsars get a kick when born in supernova explosions, but still are unsure how that happens.

    “Numerous mechanisms for producing the kick have been proposed. What we see in PSR J0002+6216 supports the idea that hydrodynamic instabilities in the supernova explosion are responsible for the high velocity of this pulsar,” Frail said.

    “We have more work to do to fully understand what’s going on with this pulsar, and it’s providing an excellent opportunity to improve our knowledge of supernova explosions and pulsars,” Schinzel said.

    Schinzel, Kerr, and Frail worked with Urvashi Rau and Sanjay Bhatnagar, both of NRAO. The scientists are reporting their results at the High Energy Astrophysics Division meeting of the American Astronomical Society in Monterey, California, and have submitted a paper to the Astrophysical Journal Letters.

    The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

    The Fermi Gamma-ray Space Telescope is an astrophysics and particle physics partnership managed by NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

    Fermi was developed in collaboration with the U.S. Department of Energy, with important contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden and the United States.

    Einstein@Home is a World Year of Physics 2005 and an International Year of Astronomy 2009 project. It is supported by the American Physical Society (APS), the US National Science Foundation (NSF), the Max Planck Society (MPG), and a number of international organizations.

    See the full article here .


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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).

     
  • richardmitnick 11:58 am on December 24, 2018 Permalink | Reply
    Tags: , , ‘PulChron’ system measures the passing of time using millisecond-frequency radio pulses from multiple fast-spinning neutron stars, , , Dame Susan Jocelyn Bell Burnell, , ESA sets clock by distant spinning stars, ,   

    From European Space Agency: “ESA sets clock by distant spinning stars” 

    ESA Space For Europe Banner

    From European Space Agency

    24 December 2018

    ESA’s technical centre in the Netherlands has begun running a pulsar-based clock. The ‘PulChron’ system measures the passing of time using millisecond-frequency radio pulses from multiple fast-spinning neutron stars.

    Operating since the end of November, this pulsar-based timing system is hosted in the Galileo Timing and Geodetic Validation Facility of ESA’s ESTEC establishment, at Noordwijk in the Netherlands, and relies on ongoing observations by a five-strong array of radio telescopes across Europe.

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    Pulsar encased in supernova bubble

    Neutron stars are the densest form of observable matter in the cosmos, formed out of the collapsed core of exploding stars. Tiny in cosmic terms, on the order of a dozen kilometres in diameter, they still have a higher mass than Earth’s Sun.

    A pulsar is a type of rapidly rotating neutron star with a magnetic field that emits a beam of radiation from its pole. Because of their spin – kept steady by their extreme density – pulsars as seen from Earth appear to emit highly regular radio bursts – so much so that in 1967 their discoverer, UK astronomer Jocelyn Bell Burnell, initially considered they might be evidence of ‘little green men’.

    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 2009

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

    3
    ESTEC

    “PulChron aims to demonstrate the effectiveness of a pulsar-based timescale for the generation and monitoring of satellite navigation timing in general, and Galileo System Time in particular,” explains navigation engineer Stefano Binda, overseeing the PulChron project.

    “A timescale based on pulsar measurements is typically less stable than one using atomic or optical clocks in the short term but it could be competitive in the very long term, over several decades or more, beyond the working life of any individual atomic clock.

    “In addition, this pulsar time scale works quite independently of whatever atomic clock technology is employed – it doesn’t rely on switches between atomic energy states but the rotation of neutron stars.”

    PulChron sources batches of pulsar measurements from the five 100-m class radio telescopes comprising the European Pulsar Timing Array – the Westerbork Synthesis Radio Telescope in the Netherlands, Germany’s Effelsberg Radio Telescope, the Lovell Telescope in the UK , France’s Nancay Radio Telescope and the Sardinia Radio Telescope in Italy.

    Westerbork Synthesis Radio Telescope, an aperture synthesis interferometer near World War II Nazi detention and transit camp Westerbork, north of the village of Westerbork, Midden-Drenthe, in the northeastern Netherlands

    MPIFR/Effelsberg Radio Telescope, in the Ahrgebirge (part of the Eifel) in Bad Münstereifel, Germany

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    Lovell Telescope, Jodrell Bank

    Nancay decametric radio telescope located in the small commune of Nançay, two hours’ drive south of Paris, France

    Sardinia Radio Telescope based in Pranu Sanguni, near Sant’Andrea Frius and San Basilio, about 35 km north of Cagliari (Sardinia, Italy).

    This multinational effort monitors 18 highly precise pulsars in the European sky to search out any timing anomalies, potential evidence of gravitational waves – fluctuations in the fabric of spacetime caused by powerful cosmic events.

    For PulChron, these radio telescope measurements are used to steer the output of an active hydrogen maser atomic clock with equipment based in the Galileo Timing and Geodetic Validation Facility – combining its extreme short- and medium-term stability with the longer-term reliability of the pulsars. A ‘paper clock’ record is also generated out of the measurements, for subsequent post-processing checks.

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    Atomic clocks at ESTEC

    ESA established the Timing and Geodetic Validation Facility in the early days of the Galileo programme, first to prepare for ESA’s two GIOVE test satellites and then in support of the world-spanning Galileo system, based on ‘Galileo System Time’ which needs to remain accurate to a few billionths of a second. The Facility continues to serve as an independent yardstick of Galileo performance, linked to monitoring stations across the globe, as well as a tool for anomaly investigation.

    Stefano adds: “The TGVF provided a perfect opportunity to host the PulChron because it is capable of integrating such new elements with little effort, and has a long tradition in time applications, having been used even to synchronise time and frequency offset of the Galileo satellites themselves.”

    5
    PulChron setup

    PulChron’s accuracy is being monitored down to a few billionths of a second using ESA’s adjacent UTC Laboratory, which harnesses three such atomic hydrogen maser clocks plus a trio of caesium clocks to produce a highly-stable timing signal, contributing to the setting of Coordinated Universal Time, UTC – the world’s time.

    The gradual diversion of pulsar time from ESTEC’s UTC time can therefore be tracked – anticipated at a rate of around 200 trillionths of a second daily.

    This project is supported through ESA’s Navigation Innovation and Support Programme (NAVISP), applying ESA’s hard-won expertise from Galileo and Europe’s EGNOS satellite augmentation system to new satellite navigation and – more widely – positioning, navigation and timing challenges.

    PulChron is being led for ESA by GMV in the UK in collaboration with the University of Manchester and the UK’s NPL National Physical Laboratory.

    See the full article here .


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    The European Space Agency (ESA), established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states. Headquartered in Paris, ESA has a staff of more than 2,000. ESA’s space flight program includes human spaceflight, mainly through the participation in the International Space Station program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. ESA science missions are based at ESTEC in Noordwijk, Netherlands, Earth Observation missions at ESRIN in Frascati, Italy, ESA Mission Control (ESOC) is in Darmstadt, Germany, the European Astronaut Centre (EAC) that trains astronauts for future missions is situated in Cologne, Germany, and the European Space Astronomy Centre is located in Villanueva de la Cañada, Spain.

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  • richardmitnick 9:00 am on July 25, 2018 Permalink | Reply
    Tags: , , , , , Dame Susan Jocelyn Bell Burnell, ,   

    From CSIROscope: Women in STEM-“The pioneer of pulsars pops into Parkes” 

    CSIRO bloc

    From CSIROscope

    25 July 2018
    Andrew Warren,
    Lucy Thackray

    1
    Dame Jocelyn with the record of her discovery

    In 1967, as a 24-year-old PhD student at Cambridge University, Dame Jocelyn Bell Burnell made one of the most significant scientific discoveries of the 20th Century when she identified and precisely analysed the first pulsar.

    Dame Jocelyn recently visited Australia, and while she was in Parkes to deliver the John Bolton lecture at the local Astrofest event, she had the chance to pop in to see our Parkes radio telescope, which you probably know as ‘The Dish’. This was the first time Dame Jocelyn had visited The Dish, which has detected more than half of the more than 2500 pulsars found since her original discovery, and when the opportunity presented itself she just ‘couldn’t resist.’ And while she was here we had the chance to catch up with her to hear her thoughts on the breakneck speed of modern science, as well as the adversity women face when pursuing a career in science.

    Puzzling pulsars

    A pulsar is a small star left behind after a normal star has died in a fiery explosion, which spins up to hundreds of times per second and sends out beams of radio waves. We now know those radio waves can be detected as a ‘pulse’ when the beam is pointed in the direction of our telescopes.

    Dame Jocelyn discovered pulsars by spotting a tiny but of ‘scruff’ in the 30 metres of chart recordings made by the telescope each day.

    “It was troubling me because it didn’t fit into any previously known category, so I was a bit puzzled by what it actually was. I started calling it ‘LGM’, which stood for Little Green Men, although I didn’t seriously believe it was little green men,” Dame Jocelyn said.

    It wasn’t until she found the second pulsar that she was able to relax a little and know that the first detection wasn’t an anomaly.

    “It wasn’t till that point I was able to stop and think aaah…this is a new branch of astronomy we’re opening up.”

    3
    Celebrating her 75th birthday at The Dish with a surprise cake

    A trailblazing pioneer

    Dame Jocelyn’s ambition when starting out was to develop a career in radio astronomy.

    “I’d already felt like a bit of a pioneering woman during my time as an undergraduate, when I was the only women in a class of fifty people doing their honours physics degree,” she said.

    And even though she’d been credited with such an important scientific discovery, she would go on to face adversity many times during her career. Perhaps the most high profile example is when the Nobel Prize in Physics was awarded to her thesis supervisor and another astronomer in 1974 for the work discovering pulsars.

    Reflecting on the incident now, Dame Jocelyn thinks “…it was far more important that there was a Nobel Prize in astrophysics, rather than what it was for, or who it went to, because it created a precedent and opened the door, because until then astrophysics hadn’t been recognised at all.”

    “There were certainly discouragements, and you sometimes had to find workarounds, but it got even harder when I married and had a child, because mothers weren’t meant to work, so I ended up working part-time for about eighteen years,” Dame Jocelyn said.

    “I knew that I needed to work… I was quite lucky that directors were prepared to give me part-time jobs, they weren’t very wonderful jobs, but they were intellectually engaging and enjoyable, and allowed me to work part-time, so that kept me sane and kept me in touch with the field.”

    “The world is getting much better at recognising women, but there’s still not parity. There’s still more room for women, and as it becomes more normal for women to do scientific things more women will come through and play a role, which will be great,” Dame Jocelyn said.

    Inspiring the next generation

    Shivani Bhandari is one of our postdoctoral astronomers who had the opportunity to hear Dame Jocelyn speak while she was in Australia.

    “It was an absolute honour to chair Dame Jocelyn’s colloquium and see her speak enthusiastically about her 50 year old discovery.” Shivani said.

    “Her struggle to pursue research in a male dominated area of study, driven by pure passion for astrophysics, is truly inspiring for female scientists, including myself.”

    4
    Our Postoctoral astronomer Shivani Bhandari with Dame Jocelyn

    Science at breakneck speed

    Dame Jocelyn also had time to reflect on the breakneck speed of modern research.

    “It’s fantastic seeing the technological change being applied to astronomy. The equipment on the Parkes telescope and others around the world is forever improving, and the pace of discovery just gets faster and faster as the equipment gets better. It leaves you a bit breathless, but it’s very exciting,” she said.

    “It’s been magnificent to see so many developments in the field since the original discovery of pulsars fifty years ago. It’s since become a major field of astronomical research, especially here at Parkes.”

    “It’s a very exciting time to be around, it’s fascinating!”

    Dame Jocelyn’s discovery

    See the full article here .


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    SKA/ASKAP radio telescope at the Murchison Radio-astronomy Observatory (MRO) in Mid West region of Western Australia

    So what can we expect these new radio projects to discover? We have no idea, but history tells us that they are almost certain to deliver some major surprises.

    Making these new discoveries may not be so simple. Gone are the days when astronomers could just notice something odd as they browse their tables and graphs.

    Nowadays, astronomers are more likely to be distilling their answers from carefully-posed queries to databases containing petabytes of data. Human brains are just not up to the job of making unexpected discoveries in these circumstances, and instead we will need to develop “learning machines” to help us discover the unexpected.

    With the right tools and careful insight, who knows what we might find.

    CSIRO campus

    CSIRO, the Commonwealth Scientific and Industrial Research Organisation, is Australia’s national science agency and one of the largest and most diverse research agencies in the world.

     
  • richardmitnick 9:12 am on March 9, 2018 Permalink | Reply
    Tags: , , , , Dame Susan Jocelyn Bell Burnell, , , Susan Jocelyn Bell Burnell   

    From ScienceNews: “50 years ago, pulsars burst onto the scene” 


    ScienceNews

    March 8, 2018
    Emily Conover

    Excerpt from the March 16, 1968 issue of Science News

    1
    LIKE CLOCKWORK Scientists reported the first discovery of a pulsar 50 years ago. The rapidly rotating neutron stars emit beams of radiation (illustrated), which sweep past Earth at regular intervals. NASA’s Goddard Space Flight Center.

    2
    The strangest signals reaching Earth

    The search for neutron stars has intensified because of a relatively small area, low in the northern midnight sky, from which the strangest radio signals yet received on Earth are being detected. If the signals come from a star, the source broadcasting the radio waves is very likely the first neutron star ever detected. — Science News, March 16, 1968

    Susan Jocelyn Bell


    Update

    That first known neutron star’s odd pulsating signature earned it the name “pulsar.” The finding garnered a Nobel Prize just six years after its 1968 announcement — although one of the pulsar’s discoverers, astrophysicist Dame Jocelyn Bell Burnell, was famously excluded.

    Dame Susan Jocelyn Bell Burnell 2009

    Since then, astronomers have found thousands of these blinking collapsed stars, which have confirmed Einstein’s theory of gravity and have been proposed as a kind of GPS for spacecraft.

    See the full article here .

    Science News is edited for an educated readership of professionals, scientists and other science enthusiasts. Written by a staff of experienced science journalists, it treats science as news, reporting accurately and placing findings in perspective. Science News and its writers have won many awards for their work; here’s a list of many of them.

    Published since 1922, the biweekly print publication reaches about 90,000 dedicated subscribers and is available via the Science News app on Android, Apple and Kindle Fire devices. Updated continuously online, the Science News website attracted over 12 million unique online viewers in 2016.

    Science News is published by the Society for Science & the Public, a nonprofit 501(c) (3) organization dedicated to the public engagement in scientific research and education.

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  • richardmitnick 9:43 pm on March 1, 2018 Permalink | Reply
    Tags: , , , , Dame Susan Jocelyn Bell Burnell, , , , ,   

    From GBO: “Pulsar Watchers Close In On Galaxy Merger History” 

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    Green Bank Radio Telescope, West Virginia, USA
    Green Bank Radio Telescope, West Virginia, USA

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    Green Bank Observatory

    2018-02-28
    Paul Vosteen

    1
    Astronomers see galaxies merging throughout the universe, some of which should result in binary supermassive black holes. Credit: NASA

    Fifty years after pulsar discovery published, massive new data set moves closer to finding very-low-frequency gravitational waves, researchers say.

    For the past twelve years, a group of astronomers have been watching the sky carefully, timing pulses of radio waves being emitted by rapidly spinning stars called pulsars, first discovered 50 years ago. These astronomers are interested in understanding pulsars, but their true goal is much more profound; the detection of a new kind of gravitational waves. With a new, more sophisticated analysis, they are much closer than ever before.

    Gravitational waves are wrinkles in space-time that stretch and squeeze the distances between objects. In 2015, a hundred years after Albert Einstein realized that accelerating massive objects should produce them, these waves were finally detected from black holes with masses roughly 30 times the mass of our sun colliding with each other. However, Einstein’s theory also predicts another kind of wave, one that comes from the mergers of black holes with masses of hundred million times the sun’s.

    Astronomers believe that nearly all galaxies have supermassive black holes at their centers. When two galaxies collide, these black holes will slowly fall toward each other, finally merging long after the initial galaxy collision. In the last stage of this process, as the two black holes spiral closer to each other, strong gravitational waves can be produced.

    While these waves travel at the speed of light, their strength varies quite slowly, on timescales ranging from months to years. This means that gravitational wave observatories on Earth can’t measure them. For that, you need an observatory with detectors light-years apart.

    “We know that galaxy mergers are an important part of galaxy growth and evolution through cosmic time. By detecting gravitational waves from supermassive binary black holes at the cores of merging galaxies, we will be able to probe how galaxies are shaped by those black holes,” said Sarah Burke-Spolaor, assistant professor at West Virginia University.

    2
    Nature publication of the discovery of pulsar B1919+21. Credit: Reproduced by permission from Springer Nature

    Fifty years ago, the February 24, 1968 edition of the journal Nature provided the solution, with the discovery of a new kind of star. This new star was curious, emitting regular radio pulses once every 1.3 seconds. Graduate student Jocelyn Bell (now Dr. Bell Burnell [now really Dame Susan Jocelyn Bell Burnell, one of the many women denied a deserved Nobel]) was the first to spot the signal, seeing it as “a bit of scruff” in her radio surveys. Zooming in on the scruff, Bell saw the regular pulses from the star.

    After first entertaining the possibility that the pulses could be the result of LGM, or “little green men,” the new star was dubbed a pulsar, with the understanding that the pulses represented the rotation rate of the star. Such a rapid rotation rate meant that the star must be small, about the size of a city. Only a few years later, a pulsar in a binary system was found, and the first mass estimate indicated that this tiny object held about one and a half times the mass of our sun.

    “Before this time, no one thought stars so small could actually exist! It wasn’t until a pulsar was found at the center of a supernova remnant in 1968 that astronomers realized that pulsars were neutron stars born in the explosions of massive stars,” said Maura McLaughlin, professor at West Virginia University.

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    After detecting unexpected signals at the same location in the sky (top left), graduate student Jocelyn Bell (right) [now Dame Susan Jocelyn Bell Burnell] observed individual pulses from the new source (bottom left) in late 1967. Credit: UK National Science & Media Museum

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    2009 Dame Susan Jocelyn Bell Burnell. Wikipedia

    The fastest pulsars, called millisecond pulsars, spin hundreds of times every second (faster than your kitchen blender!), and are the most stable natural clocks known in the universe. Pulsar astronomers around the globe are monitoring these stellar clocks in order to form a new kind of cosmic gravitational wave detector known as a “Pulsar Timing Array.” By carefully measuring when radio pulses arrive from millisecond pulsars, astronomers can track the tiny changes in the distance from the Earth to the pulsars caused by the stretching and squeezing of spacetime due to a gravitational wave.

    In the US and Canada, a group called NANOGrav (North American Nanohertz Observatory for Gravitational Waves) is searching for these gravitational waves using some of the largest telescopes in the world, including the Green Bank Telescope in West Virginia and the Arecibo Observatory in Puerto Rico.

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

    NANOGrav routinely joins forces with groups in Europe and Australia to improve their sky coverage and sensitivity. Collectively known as the International Pulsar Timing Array, the combined observations from these groups constitute the most sensitive data set in the world for searching for low-frequency gravitational waves.

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    International Pulsar Timing Array

    This month, fifty years after the publication of the first pulsar discovery, NANOGrav has submitted a pair of companion papers to The Astrophysical Journal describing eleven years of monthly observations of 45 millisecond pulsars along with the astrophysical implications of their results. For the first time, the data set includes a six-pulsar “high-frequency” sample, with measurements made every week to expand the pulsar timing array’s sensitivity range. NANOGrav is able to set sensitive upper limits that constrain the physical processes at play in galaxy mergers. As their sensitivity improves, NANOGrav is uncovering new sources of background noise that must be accounted for. Most recently, uncertainties in the pull of Jupiter on the sun have been found to affect pulsar timing. As a result, the team is implementing new computational methods to account for this, in effect determining Jupiter’s orbit more precisely than possible except by planetary missions.

    “This is the most sensitive pulsar timing dataset ever created for both gravitational wave analysis and a host of other astrophysical measurements. And with each new release, we will add more pulsars and data, which increase our sensitivity to gravitational waves”, said David Nice, professor at Lafayette College.

    Last year, the journal that announced the discovery of pulsars once again played host to a pulsar first. In November, Nature Astronomy published their first-ever article describing the gravitational wave environment that pulsar timing arrays are working to uncover. By looking at galaxy surveys, the article estimates there are about 100 supermassive black hole binaries that are close enough to affect pulsar timing array measurements. Given their expected future sensitivity, the authors state that pulsar timing arrays should be able to isolate the gravitational waves from a specific individual galaxy within about 10 years.

    “From city-sized pulsars spinning fast in galaxies to large, massive galaxies themselves and their merging central black holes, all in 50 years! That is a large step for humankind, and not one that we could have foreseen. What will the next 50 years bring? Pulsars and gravitational waves will continue to be big news, I’m sure!” said Jocelyn Bell Burnell.

    A century after Einstein first predicted them, gravitational waves were finally detected. Now, 50 years after Jocelyn Bell’s discovery, pulsars have become a new tool for measuring both gravitational waves and the distant black holes that create them. If predictions are correct, the next decade will be an exciting period of discovery for radio astronomers, pulsars, and gravitational waves!

    Links to supporting materials:
    1-page summary of 11-year results: https://nanograv.github.io/11yr_stochastic_analysis/ Submitted to the Astrophysical Journal, Dec 31, 2017

    11-Year Data Release paper: https://arxiv.org/abs/1801.01837 Submitted to The Astrophysical Journal

    Gravitational Wave Search paper: https://arxiv.org/abs/1801.02617 Submitted to The Astrophysical Journal

    See the full article here .

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    Mission Statement

    Green Bank Observatory enables leading edge research at radio wavelengths by offering telescope, facility and advanced instrumentation access to the astronomy community as well as to other basic and applied research communities. With radio astronomy as its foundation, the Green Bank Observatory is a world leader in advancing research, innovation, and education.

    History

    60 years ago, the trailblazers of American radio astronomy declared this facility their home, establishing the first ever National Radio Astronomy Observatory within the United States and the first ever national laboratory dedicated to open access science. Today their legacy is alive and well.

     
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