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  • richardmitnick 3:41 pm on July 8, 2019 Permalink | Reply
    Tags: "New Method May Resolve Difficulty in Measuring Universe's Expansion", , , , , NRAO,   

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

    From National Radio Astronomy Observatory

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

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

    NRAO/VLBA

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

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

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

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

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

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

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

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

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

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

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

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

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

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

    NRAO Banner

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    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 10:03 am on January 25, 2019 Permalink | Reply
    Tags: , , , , , NRAO,   

    From ALMA via NRAO: “Tale As Old As Time” 

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

    From ALMA

    via

    NRAO Icon
    National Radio Astronomy Observatory

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    January 7, 2019

    Hot spots in the cosmic microwave background tell us about the history and evolution of distant quasars.

    1
    Credit: NRAO/AUI/NSF

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    Image author of a quasar. Credit: NRAO / AUI / NSF.

    Synopsis: Using data from ALMA, a team of astronomers studied the growth and evolution of bubbles of hot plasma produced by active quasar HE 0515-4414. The bubble was analyzed by observing its effect on light from the cosmic microwave background. It is the first time this method has been used to directly study outflows from quasars.

    Cosmic microwave background radiation is the first light in the cosmos.

    Cosmic microwave background radiation. Stephen Hawking Center for Theoretical Cosmology U Cambridge

    The light we see began its journey when the universe was just 380,000 years old, when the temperature of the universe had finally dropped to the point where the primordial plasma of electrons and protons cooled enough to form transparent hydrogen gas. At first, the cosmic background was a nearly perfect blackbody spectrum. A blackbody spectrum is the spectrum of light caused by the temperature of an object. Sunlight, for example, is also a blackbody spectrum. Shortly after it first appeared, the cosmic blackbody was an orange glow, but during its 13.7 billion year journey the expansion of the universe shifted it to infrared and then microwave radiation. We now see this background as a faint glow of microwave light coming from all directions.

    CMB per ESA/Planck


    ESA/Planck 2009 to 2013

    The cosmic background is still a blackbody, but not a perfect one. There are small fluctuations in the background. Regions that are a bit warmer than average, and regions that are slightly cooler. Most of these fluctuations are due to variations in the early universe. Slightly warmer regions expanded to fill the vast voids between galaxies, while slightly cooler regions condensed into galaxies and clusters of galaxies.

    But some of these fluctuations are due to the tremendously long journey the light took to reach us. While traveling for billions of years, the light of the cosmic background passed through all the gas, dust and plasma between us and its source. Some of the light was absorbed. Some lost energy by scattering and now appears cooler than it would otherwise. But some of it gained energy, making the cosmic background appear warmer than it should.

    This warming process is known as the Sunyaev–Zel’dovich effect (or SZ effect). When low energy photons from the cosmic microwave background pass through a region of hot plasma, they can collide with fast-moving electrons. The photons are then scattered with a great deal of energy. So the cosmic light leaves the region warmer and brighter – leaving a “hole” in the background at low frequencies, corresponding to lower photon energies. By looking for temperature fluctuations in the cosmic background, astronomers can study regions of hot plasma.

    In a recent paper published in the Monthly Notices of the Royal Astronomical Society, a team of researchers used the SZ effect to study bubbles of hot plasma near distant quasars. Quasars are bright radio beacons in the sky. They are powered by supermassive black holes in the hearts of galaxies. As the black holes consume matter near them, they radiate tremendous energy. They are often more than 100 times brighter than the galaxy in which they live. This can create a quasar wind of ionized gas that streams away from the galaxy, similar to the way our Sun creates a solar wind. When the quasar wind collides with the diffuse and cool gas of intergalactic space, it can create bubbles of hot plasma.

    Quasars aren’t as distant as the cosmic microwave background, but they are still billions of light-years away. That means any light given off by the plasma bubbles is much too faint to be observed directly. But they can be studied through the SZ effect. In order to do that, however, you need to capture high-resolution images of the microwave background. This is where the Atacama Large Millimeter/submillimeter Array (ALMA) comes in. Located high in the Andes of northern Chile, ALMA can capture microwave images at a resolution similar to visible light images captured by the Hubble space telescope. Just as the Hubble can show us beautiful images of distant nebulae, ALMA can capture images of hot plasma bubbles.

    Using data from ALMA, the astronomers detected a bubble near the quasar HE 0515-4414. This is a hyperluminous quasar, meaning that it is extremely bright and active. But surprisingly when they used their data to measure the quasar wind, they found it was smaller than anticipated. The quasar wind is only 0.01% of the total luminosity of the quasar. Theoretical models predicted that the quasar wind should be much stronger. It seems that while quasars can create hot bubbles of plasma around a galaxy, the process isn’t particularly efficient.

    The scale of the bubble also told them it formed over a period of about 100 million years, and it will take about 600 million years to cool down. Those time scales are long enough that hot plasma bubbles could interact with cooler material in the galaxy to influence star production and the evolution of the galaxy.

    Of course this is just the first hot plasma bubble to be observed, and it’s impossible to know if HE 0515-4414 is typical or a rare exception. So the search is on to find more bubble-blowing quasars.

    See the full article here .

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    Please help promote STEM in your local schools.

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

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

    NRAO Small
    ESO 50 Large
    NAOJ

     
  • richardmitnick 1:58 pm on October 11, 2018 Permalink | Reply
    Tags: , , , CASA News, , NRAO,   

    From National Radio Astronomy Observatory: CASA News 

    NRAO Icon
    From National Radio Astronomy Observatory

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    1

    See the full article here .


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    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 2:25 pm on October 10, 2018 Permalink | Reply
    Tags: , , , , NRAO, , VLA Sky Survey Reveals First “Orphan” Gamma Ray Burst   

    From National Radio Astronomy Observatory via Manu Garcia of IAC: “VLA Sky Survey Reveals First “Orphan” Gamma Ray Burst” 


    From Manu Garcia, a friend from IAC.

    The universe around us.
    Astronomy, everything you wanted to know about our local universe and never dared to ask.

    NRAO Icon
    From National Radio Astronomy Observatory

    NRAO Banner

    October 4, 2018
    Dave Finley, Public Information Officer
    (575) 835-7302
    dfinley@nrao.edu

    1
    Credit: Bill Saxton, NRAO/AUI/NSF

    2
    Series of radio images of FIRST J1419+3940 from 1993 to 2017 show its slow fade. Credit: Law et al., Bill Saxton, NRAO/AUI/NSF

    Astronomers comparing data from an ongoing major survey of the sky using the National Science Foundation’s Karl G. Jansky Very Large Array (VLA) to data from earlier surveys likely have made the first discovery of the afterglow of a powerful gamma ray burst that produced no gamma rays detectable at Earth. The unprecedented discovery of this “orphan” gamma ray burst (GRB) offers key clues to understanding the aftermath of these highly energetic events.

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

    “GRBs emit their gamma rays in narrowly focused beams. In this case, we believe the beams were pointed away from Earth, so gamma ray telescopes did not see this event. What we found is the radio emission from the explosion’s aftermath, acting over time much as we expect for a GRB,” said Casey Law, of the University of California, Berkeley.

    While searching through data from the first epoch of observing for the VLA Sky Survey (VLASS) in late 2017, the astronomers noted that an object that appeared in images from an earlier VLA survey in 1994 did not appear in the VLASS images. They then searched for additional data from the VLA and other radio telescopes. They found that observations of the object’s location in the sky dating back as far as 1975 had not detected it until it first appeared in a VLA image from 1993.

    The object then appeared in several images made with the VLA and the Westerbork telescope in the Netherlands from 1993 through 2015. The object, dubbed FIRST J1419+3940, is in the outskirts of a galaxy more than 280 million light-years from Earth.

    “This is a small galaxy with active star formation, similar to others in which we have seen the type of GRBs that result when a very massive star explodes,” Law said.

    The strength of the radio emission from J1419+3940 and the fact that it slowly evolved over time support the idea that it is the afterglow of such a GRB, the scientists said. They suggested that the explosion and burst of gamma rays should have been seen sometime in 1992 or 1993.

    However, after searching databases from gamma ray observatories, “We could find no convincing candidate for a detected GRB from this galaxy,” Law said.

    While there are other possible explanations for the object’s behavior, the scientists said that a GRB is the most likely.

    “This is exciting, and not just because it probably is the first ‘orphan’ GRB to be discovered. It also is the oldest well-localized GRB, and the long time period during which it has been observed means it can give us valuable new information about GRB afterglows,” Law said.

    “Until now, we’ve never seen how the afterglows of GRBs behave at such late times,” noted Brian Metzger of Columbia University, co-author of the study. “If a neutron star is responsible for powering the GRB and is still active, this might give us an unprecedented opportunity to view this activity as the expanding ejecta from the supernova explosion finally becomes transparent.”

    “I’m delighted to see this discovery, which I expect will be the first of many to come from the unique investment the National Radio Astronomy Observatory (NRAO) and the National Science Foundation are making in VLASS,” said NRAO Director Tony Beasley.

    VLASS is the largest observing project in the history of the VLA. Begun in 2017, the survey will use 5,500 hours of observing time over seven years. The survey will make three complete scans of the sky visible from the VLA, roughly 80 percent of the sky. Initial images from the first round of observations now are available to astronomers.

    VLASS follows two earlier sky surveys done with the VLA. The NRAO VLA Sky Survey (NVSS), like VLASS, was an all-sky survey done from 1993 to 1996, and the FIRST (Faint Images of the Radio Sky at Twenty centimeters) survey studied a smaller portion of the sky in more detail from 1993 to 2002. The astronomers discovered FIRST J1419+3940 by comparing a 1994 image from the FIRST survey to the VLASS 2017 data.

    From 2001 to 2012, the VLA underwent a major upgrade, greatly increasing its sensitivity, or ability to image faint objects. The upgrade made possible a new, improved survey offering a rich scientific payoff. The earlier surveys have been cited more than 4,500 times in scientific papers, and scientists expect VLASS to be a valuable resource for research in the coming years.

    Law and his colleagues are publishing their findings in the Astrophysical Journal Letters.

    See the full article here .


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    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 3:07 pm on July 12, 2018 Permalink | Reply
    Tags: Blazar, , , , , , NRAO, ,   

    From NRAO via newswise: “VLA Gives Tantalizing Clues About Source of Energetic Cosmic Neutrino” 

    NRAO Icon
    From National Radio Astronomy Observatory

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    via

    2

    newswise

    1
    Supermassive black hole at core of galaxy accelerates particles in jets moving outward at nearly the speed of light. In a Blazar, one of these jets is pointed nearly straight at Earth. Credit: Sophia Dagnello, NRAO/AUI/NSF

    A single, ghostly subatomic particle that traveled some 4 billion light-years before reaching Earth has helped astronomers pinpoint a likely source of high-energy cosmic rays for the first time. Subsequent observations with the National Science Foundation’s (NSF) Karl G. Jansky Very Large Array (VLA) [depicted below] have given the scientists some tantalizing clues about how such energetic cosmic rays may be formed at the cores of distant galaxies.

    On September 22, 2017, an observatory called IceCube, made up of sensors distributed through a square kilometer of ice under the South Pole, recorded the effects of a high-energy neutrino coming from far beyond our Milky Way Galaxy.

    U Wisconsin ICECUBE neutrino detector at the South Pole

    Lunar Icecube

    IceCube DeepCore annotated

    IceCube PINGU annotated


    DM-Ice II at IceCube annotated

    Neutrinos are subatomic particles with no electrical charge and very little mass. Since they interact only very rarely with ordinary matter, neutrinos can travel unimpeded for great distances through space.

    Follow-up observations with orbiting and ground-based telescopes from around the world soon showed that the neutrino likely was coming from the location of a known cosmic object — a blazar called TXS 0506+056, about 4 billion light-years from Earth.

    3

    Like most galaxies, blazars contain supermassive black holes at their cores. The powerful gravity of the black hole draws in material that forms a hot rotating disk. Jets of particles traveling at nearly the speed of light are ejected perpendicular to the disk. Blazars are a special class of galaxies, because in a blazar, one of the jets is pointed almost directly at Earth.

    Theorists had suggested that these powerful jets could greatly accelerate protons, electrons, or atomic nuclei, turning them into the most energetic particles known in the Universe, called ultra-high energy cosmic rays. The cosmic rays then could interact with material near the jet and produce high-energy photons and neutrinos, such as the neutrino detected by IceCube.

    Cosmic rays were discovered in 1912 by physicist Victor Hess, who carried instruments in a balloon flight. Subsequent research showed that cosmic rays are either protons, electrons, or atomic nuclei that have been accelerated to speeds approaching that of light, giving some of them energies much greater than those of even the most energetic electromagnetic waves. In addition to the active cores of galaxies, supernova explosions are probable sites where cosmic rays are formed. The galactic black-hole engines, however, have been the prime candidate for the source of the highest-energy cosmic rays, and thus of the high-energy neutrinos resulting from their interactions with other matter.

    “Tracking that high-energy neutrino detected by IceCube back to TXS 0506+056 makes this the first time we’ve been able to identify a specific object as the probable source of such a high-energy neutrino,” said Gregory Sivakoff, of the University of Alberta in Canada.

    Following the IceCube detection, astronomers looked at TXS 0506+056 with numerous telescopes and found that it had brightened at wavelengths including gamma rays, X-rays, and visible light. The blazar was observed with the VLA six times between October 5 and November 21, 2017.

    “The VLA data show that the radio emission from this blazar was varying greatly at the time of the neutrino detection and for two months afterward. The radio frequency with the brightest radio emission also was changing,” Sivakoff said.

    TXS 0506+056 has been monitored over a number of years with the NSF’s Very Long Baseline Array (VLBA), a continent-wide radio telescope system that produces extremely detailed images. The high-resolution VLBA images have shown bright knots of radio emission that travel outward within the jets at speeds nearly that of light. The knots presumably are caused by denser material ejected sporadically through the jet.

    “The behavior we saw with the VLA is consistent with the emission of at least one of these knots. It’s an intriguing possibility that such knots may be associated with generating high-energy cosmic rays and thus the kind of high-energy neutrino that IceCube found,” Sivakoff said.

    The scientists continue to study TXS 0506+056. “There are a lot of exciting phenomena going on in this object,” Sivakoff concluded.

    “The era of multi-messenger astrophysics is here,” said NSF Director France Córdova. “Each messenger — from electromagnetic radiation, gravitational waves and now neutrinos — gives us a more complete understanding of the Universe, and important new insights into the most powerful objects and events in the sky. Such breakthroughs are only possible through a long-term commitment to fundamental research and investment in superb research facilities.”

    Sivakoff and numerous colleagues from institutions around the world are reporting their findings in the journal Science.

    See the full article here .


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    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 9:55 am on July 9, 2018 Permalink | Reply
    Tags: , , , , NRAO, PSO J352.4034-15.3373 (P352-15 for short), ,   

    From National Radio Astronomy Observatory via Science Alert: “BREAKING: We Just Found The Brightest Object in The Early Universe – 13 Billion Light-Years Away” 

    NRAO Icon
    From National Radio Astronomy Observatory

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    via

    Science Alert

    9 JUL 2018
    MICHELLE STARR

    1
    (NASA Goddard)

    Astronomers have found the brightest object ever discovered in the early Universe, 13 billion light-years away – a quasar from a time when our Universe was just seven percent of its current age.

    A quasar is a galaxy that orbits a supermassive black hole actively feeding on material. The light and radio emissions we see are caused by material around the black hole, called an accretion disk.

    This disk contains dust and gas swirling at tremendous speeds like water going down a drain, generating immense friction as it’s pulled by the massive gravitational force of the black hole in the centre.

    As they consume matter, these quasar black holes expel powerful jets of plasma at near light-speed from the coronae – regions of hot, swirling gas above and below the accretion disk.

    These jets are extremely bright in the radio frequency spectrum. It was this signal emanating from the newly discovered quasar, named PSO J352.4034-15.3373 (P352-15 for short), that was picked up by the Very Long Baseline Array radio telescope.

    NRAO/VLBA

    “There is a dearth of known strong radio emitters from the Universe’s youth and this is the brightest radio quasar at that epoch by a factor of 10,” said astrophysicist Eduardo Bañados of the Carnegie Institution for Science in Pasadena, California.

    2
    (Momjian, et al.; B. Saxton (NRAO/AUI/NSF))

    The VLBA’s observations showed the quasar split into three distinct components, for which there are two possible interpretations.

    The first is that the black hole is at one end, and the two other components are parts of a single jet. The second is that the black hole is in the middle, with a jet on either side.

    According to optical telescopes, which show the quasar in visible light, the position of the black hole aligns with one of the end components – making the first interpretation the most likely.

    This means that, by studying and analysing the two parts of the jet, astrophysicists may be able to measure how fast it is expanding.

    “This quasar may be the most distant object in which we could measure the speed of such a jet,” said NRAO astronomer Emmanuel Momjian.

    On the other hand, if the black hole turns out to be in the centre, it means the jets are much smaller – which would mean a much younger object, or one that is embedded in dense material that’s slowing down the jets.

    Further research will need to be done to determine which of the two scenarios is true. In the meantime, P352-15 is still a highly valuable object for study.

    It’s not as old as J1342+0928, a quasar also discovered by a team led by Bañados, from when the Universe was only five percent of its current age.

    4
    J1342+0928

    But the light of quasars can be used to study the intergalactic medium. This is because the hydrogen it travels through on its long journey to Earth changes the light’s spectrum – recently, a quasar was used in just this way to find the Universe’s missing baryonic matter in the space between galaxies.

    P352-15 has great potential as a tool of this nature.

    “We are seeing P352-15 as it was when the Universe was less than a billion years old,” said astrophysicist Chris Carilli of NRAO.

    “This is near the end of a period when the first stars and galaxies were re-ionising the neutral hydrogen atoms that pervaded intergalactic space. Further observations may allow us to use this quasar as a background ‘lamp’ to measure the amount of neutral hydrogen remaining at that time.

    “This quasar’s brightness and its great distance make it a unique tool to study the conditions and processes that prevailed in the first galaxies in the Universe.”

    The research has been published in The Astrophysical Journal Resolving the Powerful Radio-loud Quasar at z ~ 6, and A Powerful Radio-loud Quasar at the End of Cosmic Reionization.

    See the full article here .


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    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 3:59 pm on April 30, 2018 Permalink | Reply
    Tags: , , , , , , NRAO, Phased Array Feeds,   

    From National Radio Astronomy Observatory via newswise: “New Technology Offers to Broaden Vision for Radio Astronomy” 

    NRAO Icon
    National Radio Astronomy Observatory

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    1
    @newswise

    newswise

    30-Apr-2018

    2
    Infographic demonstrating the layout of the newly designed Phased Array Feed receiver that was tested on the Green Bank Telescope. Credit: NRAO/AUI/NSF; S. Dangello.



    GBO radio telescope, Green Bank, West Virginia, USA

    To accelerate the pace of discovery and exploration of the cosmos, a multi-institution team of astronomers and engineers has developed a new and improved version of an unconventional radio-astronomy imaging system known as a Phased Array Feed (PAF). This remarkable instrument can survey vast swaths of the sky and generate multiple views of astronomical objects with unparalleled efficiency.

    Looking nothing like a camera or other traditional imaging technologies – like CCDs in optical telescopes or single receivers in radio telescopes – this new Phased Array Feed design resembles a forest of miniature tree-like antennas evenly arranged on a meter-wide metal plate. When mounted on a single-dish radio telescope, specialized computers and signal processors are able to combine the signals among the antennas to create a virtual multi-pixel camera.

    This type of instrument is particularly useful in a number of important areas of astronomical research, including the study of hydrogen gas raining in on our galaxy and in searches for enigmatic Fast Radio Bursts.

    Over the years, various other radio astronomy research facilities have developed phased array receiver designs. Most, however, have not achieved the efficiency necessary to compete with classical radio receiver designs, which process one signal from one spot on the sky at a time. The value of the new PAF is that it can form multiple views (or “beams on the sky,” in radio astronomy terms) with the same efficiency as a classical receiver, which can enable faster scans of multiple astronomical targets.

    This newly developed system helps take Phased Array Feed technology from a curious area of research to a highly efficient, multipurpose tool for exploring the universe.

    Commissioning observations with the National Science Foundation’s Green Bank Telescope (GBT) using this new design show that this instrument met and exceeded all testing goals. It also achieved the lowest operating noise temperature – a normally vexing problem for clear views of the sky — of any phased array receiver to date. This milestone is critical to move the technology from an experimental design to a fully fledged observing instrument.

    The results are published in The Astronomical Journal.

    “When looking at all phased array receiver technologies currently operating or in development, our new design clearly raises the bar and gives the astronomy community a new, more rapid way of conducting large-scale surveys,” said Anish Roshi, an astronomer-engineer with the National Radio Astronomy Observatory (NRAO) and a member of the design team.

    The new PAF was designed by a consortium of institutions: the NRAO’s Central Development Laboratory, Green Bank Observatory, and Brigham Young University.

    “The collaborative work that went into designing, building, and ultimately verifying this remarkable system is truly astounding,” said NRAO Director Tony Beasley. “It highlights the fact that new and emerging radio astronomy technology can have an immense impact on research.”

    The new PAF design consists of 19 dipole antennas, radio receivers that resemble miniature umbrellas without a covering. A dipole, which simply means “two poles,” is the most basic type of antenna. Its length determines the frequency — or wavelength of radio light — it is able to receive. In the PAF radio system, the strength of the signal can vary across the surface of the array. By calculating how the signal is received by each of the antennas, the system produces what is known as a “point-spread function” – essentially, a pattern of dots concentrated in one region.

    The PAF’s computer and signal processors can calculate up to seven point-spread functions at a time, enabling the receiver to synthesize seven individual beams on the sky. The new design also allows these regions to overlap, creating a more comprehensive view of the region of space being surveyed.

    “This project brings together in one instrument a state-of-the-art, low-noise receiver design, next generation multi-channel digital radio technology, and advanced phased array modeling and beamforming,” said Bill Shillue, PAF group lead at the NRAO’s Central Development Laboratory.

    The astronomical value of the receiver was demonstrated by GBT observations of the pulsar B0329+54 and the Rosette Nebula, a star-forming region of the Milky Way filled with ionized hydrogen gas.

    Additional development and computing power could enable this same design to generated an even greater number of beams on the sky, greatly expanding its utility.

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

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    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 1:28 pm on January 4, 2018 Permalink | Reply
    Tags: , , , , NRAO, , Radio Observations Point to Likely Explanation for Neutron-Star Merger Phenomena   

    From NRAO: “Radio Observations Point to Likely Explanation for Neutron-Star Merger Phenomena” 

    NRAO Icon
    National Radio Astronomy Observatory

    NRAO Banner

    December 20, 2017
    Dave Finley, Public Information Officer
    (575) 835-7302
    dfinley@nrao.edu

    1
    Credit: NRAO/AUI/NSF: D. Berry

    Three months of observations with the National Science Foundation’s Karl G. Jansky Very Large Array (VLA) have allowed astronomers to zero in on the most likely explanation for what happened in the aftermath of the violent collision of a pair of neutron stars in a galaxy 130 million light-years from Earth. What they learned means that astronomers will be able to see and study many more such collisions.

    On August 17, 2017, the LIGO and VIRGO gravitational-wave observatories combined to locate the faint ripples in spacetime caused by the merger of two superdense neutron stars.


    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)

    It was the first confirmed detection of such a merger and only the fifth direct detection ever of gravitational waves, predicted more than a century ago by Albert Einstein.

    The gravitational waves were followed by outbursts of gamma rays, X-rays, and visible light from the event. The VLA detected the first radio waves coming from the event on September 2. This was the first time any astronomical object had been seen with both gravitational waves and electromagnetic waves.

    The timing and strength of the electromagnetic radiation at different wavelengths provided scientists with clues about the nature of the phenomena created by the initial neutron-star collision. Prior to the August event, theorists had proposed several ideas — theoretical models — about these phenomena. As the first such collision to be positively identified, the August event provided the first opportunity to compare predictions of the models to actual observations.

    Astronomers using the VLA, along with the Australia Telescope Compact Array and the Giant Metrewave Radio Telescope in India, regularly observed the object from September onward. The radio telescopes showed the radio emission steadily gaining strength. Based on this, the astronomers identified the most likely scenario for the merger’s aftermath.

    CSIRO ATCA at the Paul Wild Observatory, about 25 km west of the town of Narrabri in rural NSW about 500 km north-west of Sydney, AU

    Giant Metrewave Radio Telescope, an array of thirty telecopes, located near Pune in India

    “The gradual brightening of the radio signal indicates we are seeing a wide-angle outflow of material, traveling at speeds comparable to the speed of light, from the neutron star merger,” said Kunal Mooley, now a National Radio Astronomy Observatory (NRAO) Jansky Postdoctoral Fellow hosted by Caltech.

    The observed measurements are helping the astronomers figure out the sequence of events triggered by the collision of the neutron stars.

    The initial merger of the two superdense objects caused an explosion, called a kilonova, that propelled a spherical shell of debris outward. The neutron stars collapsed into a remnant, possibly a black hole, whose powerful gravity began pulling material toward it. That material formed a rapidly-spinning disk that generated a pair of narrow, superfast jets of material flowing outward from its poles.

    If one of the jets were pointed directly toward Earth, we would have seen a short-duration gamma-ray burst, like many seen before, the scientists said.

    “That clearly was not the case,” Mooley said.

    Some of the early measurements of the August event suggested instead that one of the jets may have been pointed slightly away from Earth. This model would explain the fact that the radio and X-ray emission were seen only some time after the collision.

    “That simple model — of a jet with no structure (a so-called top-hat jet) seen off-axis — would have the radio and X-ray emission slowly getting weaker. As we watched the radio emission strengthening, we realized that the explanation required a different model,” said Alessandra Corsi, of Texas Tech University.

    The astronomers looked to a model published in October by Mansi Kasliwal of Caltech, and colleagues, and further developed by Ore Gottlieb, of Tel Aviv University, and his colleagues. In that model, the jet does not make its way out of the sphere of explosion debris. Instead, it gathers up surrounding material as it moves outward, producing a broad “cocoon” that absorbs the jet’s energy.

    The astronomers favored this scenario based on the information they gathered from using the radio telescopes. Soon after the initial observations of the merger site, the Earth’s annual trip around the Sun placed the object too close to the Sun in the sky for X-ray and visible-light telescopes to observe. For weeks, the radio telescopes were the only way to continue gathering data about the event.

    “If the radio waves and X-rays both are coming from an expanding cocoon, we realized that our radio measurements meant that, when NASA’s Chandra X-ray Observatory could observe once again, it would find the X-rays, like the radio waves, had increased in strength,” Corsi said.

    Mooley and his colleagues posted a paper with their radio measurements, their favored scenario for the event, and this prediction online on November 30. Chandra was scheduled to observe the object on December 2 and 6.

    “On December 7, the Chandra results came out, and the X-ray emission had brightened just as we predicted,” said Gregg Hallinan, of Caltech.

    “The agreement between the radio and X-ray data suggests that the X-rays are originating from the same outflow that’s producing the radio waves,” Mooley said.

    “It was very exciting to see our prediction confirmed,” Hallinan said. He added, “An important implication of the cocoon model is that we should be able to see many more of these collisions by detecting their electromagnetic, not just their gravitational, waves.”

    Mooley, Hallinan, Corsi, and their colleagues reported their findings in the scientific journal Nature.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    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 2:35 pm on December 31, 2017 Permalink | Reply
    Tags: , , , , , , NRAO,   

    From NRAO: “Next-generation U.S. Radio Telescope Development Begins” 

    NRAO Icon
    National Radio Astronomy Observatory

    NRAO Banner

    September 14, 2017
    Dave Finley, Public Information Officer
    (575) 835-7302
    dfinley@nrao.edu

    Planning begins for next leap forward in research capability.

    1
    Artist’s conception of the multi-antenna Next generation VLA (ngVLA). Credit: Bill Saxton, NRAO/AUI/NSF

    The National Radio Astronomy Observatory (NRAO) and Associated Universities, Inc. (AUI) are launching a new initiative to design a next-generation radio telescope with scientific capabilities far beyond those provided by any existing or currently proposed observatory.

    Building on the success of one of the National Science Foundation’s (NSF) flagship observatories, the Karl G. Jansky Very Large Array (VLA), NRAO and AUI are beginning a two-year project to explore the science opportunities, design concepts, and technologies needed to construct a new class of radio telescope.

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

    This proposed array, consisting of more than 200 antennas, would extend across the desert southwest of the United States and into northern Mexico.

    Currently dubbed the next-generation Very Large Array, or ngVLA for short, the new research facility will be designed to provide the next leap forward in our understanding of planets, galaxies, black holes, and fundamental physics.

    “The capabilities of the ngVLA are the only means of answering a broad range of critical scientific questions in modern astronomy,” said NRAO Director Tony Beasley. “The ngVLA will open a new window on the Universe, and its scientific and technological innovations promise great contributions to society across many dimensions, including economic development, education, and others,” he added.

    Funding for the new initiative was provided by the National Science Foundation’s Division of Astronomical Sciences, allowing NRAO to re-profile $11M in funding planned for instrument development over a longer time period into a focused two-year effort. This large telescope initiative was included in AUI’s successful proposal to the NSF to manage NRAO over the decade just starting, and NSF’s decision allows NRAO to accelerate the early design studies. This will enable the ngVLA concept to be more fully developed for the next U.S. astronomy Decadal Survey, commencing in 2019-2020, where all major new instruments and capabilities are considered by the research community. A key use of the funding will be exploration of the high-performance antennas that will collect the astronomical signals for analysis.

    “We’re very eager to get this effort underway,” said ngVLA Project Scientist Eric Murphy. “Along with partners and advisors from throughout the astronomical community, we look forward to the challenge of meeting the research needs of the coming decades,” he added.

    “Associated Universities, Inc., recognizes ngVLA as the future of radio astronomy in North America, and we are excited to start developing this new concept,” said AUI President Ethan Schreier. “New Mexico is home to many great astronomical facilities, and ngVLA will continue this proud tradition,“ he said.

    NSF’s Division of Astronomical Sciences is responsible for funding the VLA, the North American share of the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, and other ground-based astronomical observatories. NSF is an independent federal agency that supports research and education in all non-medical fields of science, and in 2017 provided $75 Million to NRAO to support radio astronomy research in the U.S. and in Chile.

    In New Mexico, planning has begun for the design effort. Last June, NRAO hosted a workshop in Socorro on requirements and concepts for the new telescope. The workshop was attended by astronomers from a variety of specialties and institutions. In the near future, NRAO anticipates working with university and industrial partners as the project advances.

    More information on ngVLA can be found here and here.

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

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    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 6:46 pm on December 28, 2017 Permalink | Reply
    Tags: , , , , NRAO, , The Very Large Array Sky Survey (VLASS),   

    From NRAO: “The Very Large Array Sky Survey (VLASS)” This is huge, with many great videos at the end 

    NRAO Icon
    National Radio Astronomy Observatory

    NRAO Banner

    Mapping the Radio Universe

    Most of the marvels of the universe are invisible to us without technological assistance. Visible light is only a small slice of the electromagnetic spectrum, ranging from tiny, high-energy gamma rays to long, slow-moving radio waves. So, imagine if you could put on radio glasses to view a range of light obscured from all but the most sophisticated telescopes. What would you see? You might be able to peer through dusty clouds and view the beginning stages of star formation or watch the intermittent lighthouse bursts from pulsars, if the neutron star happens to be pointing towards earth at the right angle. What would it be like to see an array of energetic particles dancing around the Sun’s corona?

    On September 7, 2017, the Jansky Very Large Array (VLA) pointed its antennas toward the northern sky and began one of the largest all-sky radio observations in 40 years.

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

    From its vantage point in New Mexico, the VLA Sky Survey (VLASS) will map 80 percent of the sky in 3 phases over 7 years and is expected to catalog approximately 10 million new radio sources. The survey will collect data from powerful, cosmic sources that will allow the scientific community to image supernovae explosions, gamma-ray bursts, and the collisions of neutron stars that are obscured from visible-light telescopes by thick clouds of dust. The VLA’s ability to see through dust and clouds will make the survey an important tool in the discovery of new radio objects.

    1
    Optical Sky – Milky Way Galaxy 9/7/2017 The beginning

    3
    Epoch 1.1B September 13, 2017 – January 29, 2018

    4
    Epoch 1.1 BnA February 02, 2018 – February 19, 2018

    5
    Epoch 1.2B January 23, 2019 – June 03, 2019

    6
    Epoch 1.2 BnA June 07, 2019 – June 24, 2019

    End of First Epoch

    7
    Epoch 2.1B May 20, 2020- Octpber 5, 2020

    Beginning of Epoch 2. We expect to cover powerful cosmic explosions, such as supernovae, gamma ray bursts, and the collision of neutron stars. This new cycle will allow us to monitor any changes in radio sources.

    8
    Epoch 2.1 BnA October 9, 2020 – October 26, 2020

    The mid-point

    9
    Epoch 2.2B September 29, 2021 – February 14, 2022

    10
    Epoch 2.2 BnA February 18, 2022 – March 07, 2022

    At this point in the survey, we’ve viewed 80 percent of the sky twice over.

    Beginning of Epoch 3 We have two reference surveys in which to compare radio sources.

    11
    Epoch 3.1B February 01, 2023 – June 12, 2023

    12
    Hybrid configuration 3.1 BnA

    Epoch 3.1 BnA JUne 16, 2023 – July 03, 2023

    The penultimate view

    13
    Epoch 3.2B May 29, 2024 – October 07, 2024

    14
    Epoch 3.2 BnA Octiber 11, 2024 – October 28, 2024

    The end. We now have 3 complete, in-depth views over 80 percent of the sky. Data from all three phases will be combined to make even more detailed images.

    Sky Surveys have been integral to astronomy for millennia. As far back as the 2nd century BC, Hipparcos and astronomers of the Han dynasty have observed and recorded astronomical phenomenon and seasonal celestial changes from the night sky. Sky surveys are a way to map, in a systematic way, the universe and its constituents parts, opening up the observational impact of how celestial objects, especially those beyond our solar system, change with time. Within the last century, as technology has allowed for the expansion of observations beyond the traditional visible wavelength window, sky surveys have proved to be a fundamental part of multi-wavelength astronomy.

    The Very Large Array Sky Survey (VLASS) represents our third radio survey project in the last twenty years. The VLA has undergone a complete technical transformation, since our last two surveys: the NRAO VLA Sky Survey (NVSS) and Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) in 1992. From 2001-2012, the original electronic system, designed and built during the 1970’s, has been replaced with state-of-the-art technology that vastly expanded the VLA’s observing capabilities. This major upgrade has transformed the VLA into a completely new scientific tool. Our next generation sky survey will harness the tremendously improved capabilities of the VLA, resulting in a unique and extremely valuable tool for frontier research over a diverse range of scientific fields.

    VLASS is designed to produce a large collection of radio data available to wide range of scientists within the astronomical community. Our science goal is to produce a radio, all-sky survey that will benefit the entire astronomical community. As VLASS completes its three scans of the sky separated by approximately 32 months, new developments in data processing techniques will allow scientists an opportunity to download data instantly on potentially millions of astronomical radio sources. This data from all three cycles will be combined to make even more detailed radio images, creating the largest-ever celestial radio census. Scientists will be able to compare images from the individual observation cycles, allowing for the discovery of newly-appearing sources or short-lived (transient) objects.

    Fundamentally, astronomy is about exploring — making images of the sky to see what is out there, and our VLA sky survey is a new and powerful resource for this exploration.

    14
    B configuration

    VLASS Configurations
    • B Configuration

    The antennas in the Very Large Array are used like the zoom lens in a camera. When they are in the B configuration, the telescopes extend over the 11 kilometers (7.08 mile) length of each arm. In this configuration, we have the second largest magnification and can see great detail. The size of the array gradually decreases with the C configurations until, in the D configuration, the telescopes are all placed within 0.6 kilometer (0.4 mile) of the center.
    • BnA Configuration

    The iconic “Y” shape of the VLA has a specific function. The wider an array, the bigger its eye is, and the more detail it can see out in space. The VLA’s unique shape gives us three long arms of nine telescopes each. It also gives our scientists the flexibility of stretching the arms when we need to zoom in for more detail.

    Check out these videos for more information on the different VLA configurations and the amazing machines that move the 230 ton antennas around.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    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).

     
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