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  • richardmitnick 10:05 am on September 7, 2021 Permalink | Reply
    Tags: "Something Mysterious Near The Galactic Center Is Flashing Radio Signals", A newly discovered source of radio signals-called ASKAP J173608.2-321635, , , , MeerKAT/SARAO – SKA South Africa, Radio Astronomy, , SKA ASKAP Pathfinder Radio Telescope,   

    From University of Sydney (AU) via Science Alert (US) : “Something Mysterious Near The Galactic Center Is Flashing Radio Signals” 

    U Sidney bloc

    From University of Sydney (AU)

    via

    ScienceAlert

    Science Alert (US)

    7 SEPTEMBER 2021
    MICHELLE STARR

    1
    The galactic center in radio wavelengths. Credit: MeerKAT/SARAO – SKA South Africa.

    As our eyes on the sky grow ever more sensitive, we’re going to find more and more things we’ve never seen before.

    Such is the case for a newly discovered source of radio signals, located not far from the center of the galaxy. It’s called ASKAP J173608.2-321635, and astronomers have been unable to figure out what kind of cosmic object best fits its weird properties.

    Their paper has been accepted for publication in The Astrophysical Journal.

    “We have presented the discovery and characterization of ASKAP J173608.2-321635: a highly-polarized, variable radio source located near the Galactic Center and with no clear multi-wavelength counterpart,” explain a team of astronomers led by Ziteng Wang of the University of Sydney in Australia.

    “ASKAP J173608.2-321635 may represent part of a new class of objects being discovered through radio imaging surveys.”

    ASKAP J173608.2-32163 was discovered using the Australian Square Kilometre Array Pathfinder (ASKAP), one of the most sensitive radio telescopes ever built, designed to peer deep into the radio Universe.

    It’s already proven adept at finding things we have never seen before, such as Odd Radio Circles (we don’t know what those are, yet), undiscovered galaxies, and mysterious fast radio bursts.

    ASKAP J173608.2-32163 might turn out to be a known type of cosmic object, but if it does, it could end up stretch the definition of whatever object that is.

    It’s highly variable, emitting radio waves for weeks at a time, and then disappearing on rapid timescales. The signal is also highly polarized – that is, the orientation of the oscillation of the electromagnetic wave is twisted, both linearly and circularly.

    ASKAP J173608.2-32163 is also quite a tricky beast to spot. The object, whatever it is, had not been seen before the ASKAP detections, made during a pilot survey of the sky to look for transient radio sources. Between April 2019 and August 2020, the signal appeared in the data 13 times.

    Follow-up observations in April and July of 2020 using a different radio telescope, Murriyang in Parkes, Australia, yielded nothing.

    But the MeerKAT radio telescope in South Africa got a hit, in February 2021.

    The Australia Telescope Compact Array (ATCA) also made a detection in April 2021.

    This supports and validates the ASKAP detections, but also suggests that the source is quite elusive – there were no MeerKAT or ATCA detections prior to that date. Nor did the source appear in X-ray and near-infrared observations, nor in archives of radio data collected by multiple instruments that the researchers checked.

    Which leaves a pretty fascinating mystery. The polarization suggests scattering and magnetization, possibly partially due to dust and magnetic fields in the interstellar medium between us and the source, although it’s possible that the source itself is also highly magnetized.

    All up, it’s really hard to figure out what the source might be. There are several types of stars that are known to vary in radio wavelengths, such as stars that flare frequently, or close binaries with active chromospheres, or that eclipse each other. The non-detection in X-ray and near-infrared wavelengths makes this unlikely though.

    Flaring stars usually have X-ray emission that corresponds to the radio emission, and the vast majority of stars have ratios of near-infrared emission that should be detectable.

    Nor is a pulsar likely: a type of neutron star with sweeping beams of radio light, like a cosmic lighthouse. Pulsars have regular periodicity, on a timescale of hours, and ASKAP J173608.2-32163 was detected fading, which is inconsistent with pulsars. Also, there was a three-month span with no detections, which is also inconsistent with pulsars.

    X-ray binaries, gamma-ray bursts, and supernovae were also all ruled out.

    However, the object does share some properties with a type of mysterious signal spotted near the galactic center. These are known as Galactic Center Radio Transients (GCRT), three of which were identified in the 2000s, and more of which are awaiting confirmation.

    These sources are also yet to be explained, but they have several features in common with ASKAP J173608.2-32163.

    If ASKAP J173608.2-32163 is a GCRT, ASKAP’s detection could help us find more such sources, and figure out what they are.

    “Given that ASKAP J173608.2-321635 is typically not detected and can turn off on timescales from several weeks to as quickly as a day, our sparse sampling (12 epochs over 16 months) suggests that there could be other similar sources in these fields,” the researchers write.

    “Increasing the survey cadence and comparing the results of this search to other regions will help us understand how truly unique ASKAP J173608.2-321635 is and whether it is related to the Galactic plane, which should ultimately help us deduce its nature.”

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    University of Sydney (AU)
    Our founding principle as Australia’s first university, U Sydney was that we would be a modern and progressive institution. It’s an ideal we still hold dear today.

    When Charles William Wentworth proposed the idea of Australia’s first university in 1850, he imagined “the opportunity for the child of every class to become great and useful in the destinies of this country”.

    We’ve stayed true to that original value and purpose by promoting inclusion and diversity for the past 160 years.

    It’s the reason that, as early as 1881, we admitted women on an equal footing to male students. The University of Oxford (UK) didn’t follow suit until 30 years later, and Jesus College at The University of Cambridge (UK) did not begin admitting female students until 1974.

    It’s also why, from the very start, talented students of all backgrounds were given the chance to access further education through bursaries and scholarships.

    Today we offer hundreds of scholarships to support and encourage talented students, and a range of grants and bursaries to those who need a financial helping hand.

    The University of Sydney (AU) is an Australian public research university in Sydney, Australia. Founded in 1850, it is Australia’s first university and is regarded as one of the world’s leading universities. The university is known as one of Australia’s six sandstone universities. Its campus, spreading across the inner-city suburbs of Camperdown and Darlington, is ranked in the top 10 of the world’s most beautiful universities by the British Daily Telegraph and the American Huffington Post.The university comprises eight academic faculties and university schools, through which it offers bachelor, master and doctoral degrees.

    The QS World University Rankings ranked the university as one of the world’s top 25 universities for academic reputation, and top 5 in the world and first in Australia for graduate employability. It is one of the first universities in the world to admit students solely on academic merit, and opened their doors to women on the same basis as men.

    Five Nobel and two Crafoord laureates have been affiliated with the university as graduates and faculty. The university has educated seven Australian prime ministers, two governors-general of Australia, nine state governors and territory administrators, and 24 justices of the High Court of Australia, including four chief justices. The university has produced 110 Rhodes Scholars and 19 Gates Scholars.

    The University of Sydney (AU) is a member of the Group of Eight, CEMS, the Association of Pacific Rim Universities and the Association of Commonwealth Universities.

     
  • richardmitnick 1:38 pm on September 4, 2021 Permalink | Reply
    Tags: "Dust in the central parsecs of unobscured AGN provide more challenges to the torus", , , , Radio Astronomy,   

    From IAC Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias] (ES) : “Dust in the central parsecs of unobscured AGN provide more challenges to the torus” 

    Instituto de Astrofísica de Andalucía

    From IAC Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias] (ES)

    04/09/2021

    M Almudena, Prieto Escudero, J. Nadolny
    Instituto de Astrofísica de Canarias (IAC)

    J. A. Fernández-Ontiveros
    Istituto di Astrofisica e Planetologia Spaziali (IT)

    M. Mezcua
    Institute of Space Studies of Catalonia [Institut d’Estudis Espacials de Catalunya](ES)

    1
    The image shows the process of nuclear feeding of a black hole in the galaxy NGC 1566, and how the dust filaments – seen in white-blue colors- are trapped and rotating in a spiral around the black hole until the black hole swallows them. Credit: ESO.

    The black holes at the centres of galaxies are the most mysterious objects in the Universe, not only because of the huge quantities of material within them, millions of times the mass of the Sun, but because of the incredibly dense concentration of matter in a volume no bigger than that of our Solar System. When they capture matter from their surroundings they become active, eventually giving rise to the ejection of huge amounts of energy. It is however difficult to detect the black hole during these capture episodes because the event is rare. We detected long and narrow dust filaments surrounding and feeding the black hole in the centres of several galaxies. These filaments could furthermore be the natural cause of the darkening of the centre of many galaxies when their nuclear black holes become active. The discovery of these filaments and the understanding of their nature have been made possible by using extremely sharp images obtained with the Hubble Space Telescope, the Very Large Telescope (VLT) at the European Southern Observatory (ESO), and the Atacama Large Millimetre Array (ALMA) in Chile.

    Each of these images provides us with a different view of the various states of the interstellar medium in which these filaments reside. Their combined analysis led to a direct visualisation of filaments feeding the black hole. A first estimate of the amount of matter in the filaments indicates an inflow equivalent to the mass of the Sun per year.

    Science paper:
    MNRAS

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    IAC Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias] (ES) operates two astronomical observatories in the Canary Islands:

    Roque de los Muchachos Observatory on La Palma
    Teide Observatory on Tenerife.

    The seeing statistics at ORM make it the second-best location for optical and infrared astronomy in the Northern Hemisphere, after Mauna Kea Observatory Hawaii (US).

    Maunakea Observatories Hawai’i (US) altitude 4,213 m (13,822 ft)

    The site also has some of the most extensive astronomical facilities in the Northern Hemisphere; its fleet of telescopes includes the 10.4 m Gran Telescopio Canarias, the world’s largest single-aperture optical telescope as of July 2009, the William Herschel Telescope (second largest in Europe), and the adaptive optics corrected Swedish 1-m Solar Telescope.

    Gran Telescopio Canarias [Instituto de Astrofísica de Canarias ](ES) sited on a volcanic peak 2,267 metres (7,438 ft) above sea level.

    The observatory was established in 1985, after 15 years of international work and cooperation of several countries with the Spanish island hosting many telescopes from Britain, The Netherlands, Spain, and other countries. The island provided better seeing conditions for the telescopes that had been moved to Herstmonceux by the Royal Greenwich Observatory, including the 98 inch aperture Isaac Newton Telescope (the largest reflector in Europe at that time). When it was moved to the island it was upgraded to a 100-inch (2.54 meter), and many even larger telescopes from various nations would be hosted there.

    Teide Observatory [Observatorio del Teide], IAU code 954, is an astronomical observatory on Mount Teide at 2,390 metres (7,840 ft), located on Tenerife, Spain. It has been operated by the Instituto de Astrofísica de Canarias since its inauguration in 1964. It became one of the first major international observatories, attracting telescopes from different countries around the world because of the good astronomical seeing conditions. Later the emphasis for optical telescopes shifted more towards Roque de los Muchachos Observatory on La Palma.

     
  • richardmitnick 8:30 pm on September 2, 2021 Permalink | Reply
    Tags: "Stellar Collision Triggers Supernova Explosion", Astronomers have found dramatic evidence that a black hole or neutron star spiraled its way into the core of a companion star and caused that companion to explode as a supernova., , , , , Radio Astronomy, The object designated VT 1210+4956.   

    From National Radio Astronomy Observatory (US) : “Stellar Collision Triggers Supernova Explosion” 

    From National Radio Astronomy Observatory (US)

    NRAO Banner

    September 2, 2021

    Media Contact:
    Dave Finley, Public Information Officer
    (505) 241-9210
    dfinley@nrao.edu

    1
    Credit: Bill Saxton, NRAO/Associated Universities Inc(US)/The National Science Foundation (US).

    Astronomers have found dramatic evidence that a black hole or neutron star spiraled its way into the core of a companion star and caused that companion to explode as a supernova. The astronomers were tipped off by data from the Very Large Array Sky Survey (VLASS), a multi-year project using the National Science Foundation’s Karl G. Jansky Very Large Array (VLA) [below].

    “Theorists had predicted that this could happen, but this is the first time we’ve actually seen such an event,” said Dillon Dong, a graduate student at The California Institute of Technology (US) and lead author on a paper reporting the discovery in the journal Science.

    The first clue came when the scientists examined images from VLASS, which began observations in 2017, and found an object brightly emitting radio waves but which had not appeared in an earlier VLA sky survey, called Faint Images of the Radio Sky at Twenty centimeters (FIRST). They made subsequent observations of the object, designated VT 1210+4956, using the VLA and the Keck telescope in Hawaii.

    They determined that the bright radio emission was coming from the outskirts of a dwarf, star-forming galaxy some 480 million light-years from Earth. They later found that an instrument aboard the International Space Station had detected a burst of X-rays coming from the object in 2014.

    The data from all these observations allowed the astronomers to piece together the fascinating history of a centuries-long death dance between two massive stars. Like most stars that are much more massive than our Sun, these two were born as a binary pair, closely orbiting each other. One of them was more massive than the other and evolved through its normal, nuclear fusion-powered lifetime more quickly and exploded as a supernova, leaving behind either a black hole or a super dense neutron star.

    The black hole or neutron star’s orbit grew steadily closer to its companion, and about 300 years ago it entered the companion’s atmosphere, starting the death dance. At this point, the interaction began spraying gas away from the companion into space. The ejected gas, spiraling outward, formed an expanding, donut-shaped ring, called a torus, around the pair.

    Eventually, the black hole or neutron star made its way inward to the companion star’s core, disrupting the nuclear fusion producing the energy that kept the core from collapsing of its own gravity. As the core collapsed, it briefly formed a disk of material closely orbiting the intruder and propelled a jet of material outward from the disk at speeds approaching that of light, drilling its way through the star.

    “That jet is what produced the X-rays seen by the MAXI instrument aboard the International Space Station, and this confirms the date of this event in 2014,” Dong said.

    The collapse of the star’s core caused it to explode as a supernova, following its sibling’s earlier explosion.

    “The companion star was going to explode eventually, but this merger accelerated the process,” Dong said.

    The material ejected by the 2014 supernova explosion moved much faster than the material thrown off earlier from the companion star, and by the time VLASS observed the object, the supernova blast was colliding with that material, causing powerful shocks that produced the bright radio emission seen by the VLA.

    “All the pieces of this puzzle fit together to tell this amazing story,” said Gregg Hallinan of Caltech. “The remnant of a star that exploded a long time ago plunged into its companion, causing it, too, to explode,” he added.

    The key to the discovery, Hallinan said, was VLASS, which is imaging the entire sky visible at the VLA’s latitude — about 80 percent of the sky — three times over seven years. One of the objectives of doing VLASS that way is to discover transient objects, such as supernova explosions, that emit brightly at radio wavelengths. This supernova, caused by a stellar merger, however, was a surprise.

    “Of all the things we thought we would discover with VLASS, this was not one of them,” Hallinan said.

    See the full article here .
    See also the full article from Caltech here.


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

    Please help promote STEM in your local schools.

    Stem Education Coalition
    The National Radio Astronomy Observatory (NRAO)(US) is a Federally Funded Research and Development Center of the United States National Science Foundation operated under cooperative agreement by Associated Universities, Inc for the purpose of radio astronomy. NRAO designs, builds, and operates its own high sensitivity radio telescopes for use by scientists around the world.

    Charlottesville, Virginia(US)

    The NRAO headquarters is located on the campus of the University of Virginia (US). The North American ALMA Science Center (US) and the NRAO Technology Center and Central Development Laboratory are also in Charlottesville, Virginia.

    Green Bank, West Virginia(US)

    NRAO was, until October 2016, the operator of the world’s largest fully steerable radio telescope, the Robert C. Byrd Green Bank Telescope, which stands near Green Bank, West Virginia.

    The observatory contains several other telescopes, among them the 140-foot (43 m) telescope that utilizes an equatorial mount uncommon for radio telescopes, three 85-foot (26 m) telescopes forming the Green Bank Interferometer, a 40-foot (12 m) telescope used by school groups and organizations for small scale research, a fixed radio “horn” built to observe the radio source Cassiopeia A, as well as a reproduction of the original antenna built by Karl Jansky while he worked for Bell Labs to detect the interference that was discovered to be previously unknown natural radio waves emitted by the universe.

    Green Bank is in the National Radio Quiet Zone, which is coordinated by NRAO for protection of the Green Bank site as well as the Sugar Grove, West Virginia monitoring site operated by the NSA. The zone consists of a 13,000-square-mile (34,000 km2) piece of land where fixed transmitters must coordinate their emissions before a license is granted. The land was set aside by the Federal Communications Commission in 1958. No fixed radio transmitters are allowed within the area closest to the telescope. All other fixed radio transmitters including TV and radio towers inside the zone are required to transmit such that interference at the antennas is minimized by methods including limited power and using highly directional antennas. With the advent of wireless technology and microprocessors in everything from cameras to cars, it is difficult to keep the sites free of radio interference. To aid in limiting outside interference, the area surrounding the Green Bank Observatory was at one time planted with pines characterized by needles of a certain length to block electromagnetic interference at the wavelengths used by the observatory. At one point, the observatory faced the problem of North American flying squirrels tagged with United States Fish and Wildlife Service telemetry transmitters. Electric fences, electric blankets, faulty automobile electronics, and other radio wave emitters have caused great trouble for the astronomers in Green Bank. All vehicles on the premises are powered by diesel motors to minimize interference by ignition systems.

    Socorro, New Mexico

    The NRAO’s facility in Socorro is the Pete Domenici Array Operations Center (AOC). Located on the New Mexico Technical University campus, the AOC serves as the headquarters for the NRAO Jansky Very Large Array(VLA), which was the setting for the 1997 movie Contact, and is also the control center for the NRAO Very Long Baseline Array (VLBA)(US). The ten VLBA telescopes are in Hawaii, the U.S. Virgin Islands, and eight other sites across the continental United States.

    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.

    San Pedro de Atacama, Chile

    The Atacama Large Millimeter Array (ALMA) site in Chile is at ~5000 m (~16,500 ft) altitude near Cerro Chajnantor in northern Chile.[10] This is about 40 km (about 25 miles) east of the historic village of San Pedro de Atacama, 130 km (about 80 miles) southeast of the mining town of Calama, and about 275 km (about 170 miles) east-northeast of the coastal port of Antofagasta.

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

     
  • richardmitnick 9:09 pm on August 19, 2021 Permalink | Reply
    Tags: "Scientists detect never-before-seen radio waves from nearby stars and distant galaxies", , , , , , Evolutionary Map of the Universe (EMU), Radio Astronomy   

    From University of Keele (UK): “Scientists detect never-before-seen radio waves from nearby stars and distant galaxies” 

    From University of Keele (UK)

    19 August 2021

    1
    Scientists have measured thousands of nearby stars and far away galaxies that have never been identified before at radio wavelengths, while studying a galactic body that neighbours our own Milky Way galaxy – the Large Magellanic Cloud.

    Led by Led by University of Keele (UK PhD student Clara M. Pennock and Reader in Astrophysics, Dr Jacco van Loon, the international team of researchers used the Australian Square Kilometre Array Pathfinder (ASKAP) telescope to “photograph” the Cloud at radio wavelengths and study the stellar structures within, taking some of the sharpest radio images of the Cloud ever recorded.

    The Large Magellanic Cloud is a galaxy which borders our own, the Milky Way, and is known as a satellite dwarf spiral galaxy. It is around 158,200 light years away from Earth and is home to tens of millions of stars.

    Due to its proximity to the Milky Way, it provides an excellent benchmark for researchers studying fundamental questions, such as how stars form and how galaxies are structured.

    The researchers not only took the sharpest radio images of the Cloud ever recorded, but during their analysis they also studied the stars themselves which form the Cloud’s structure, including the Tarantula Nebula, the most active star-formation region in the Local Group.

    Furthermore, newly detected radio emission has also been studied from distant galaxies in the background as well as stars in the foreground from our own Milky Way.

    This study, published in MNRAS, forms part of the Evolutionary Map of the Universe (EMU) Early Science Project, which will observe the entire Southern sky and is predicted to detect around 40 million galaxies. The data will ultimately be used to give researchers a clearer picture of how galaxies, and their stars, have evolved throughout time.

    Lead author Clara Pennock from University of Keele (UK) said: “The sharp and sensitive new image reveals thousands of radio sources we’ve never seen before. Most of these are actually galaxies millions or even billions of light years beyond the Large Magellanic Cloud. We typically see them because of the supermassive black holes in their centres which can be detected at all wavelengths, especially radio. But we now also start finding many galaxies in which stars are forming at a tremendous rate. Combining this data with previous observations from X-ray, optical and infrared telescopes will allow us to explore these galaxies in extraordinary detail.”

    Dr Jacco van Loon, Reader in Astrophysics at University of Keele (UK) said: “With so many stars and nebulae packed together, the increased sharpness of the image has been instrumental in discovering radio emitting stars and compact nebulae in the LMC. We see all sorts of radio sources, from individual fledgling stars to planetary nebulae that result from the death of stars like the Sun.”

    Co-author Professor Andrew Hopkins, from Macquarie University(AU) in Sydney, and leader of the EMU survey, added: “It’s gratifying to see these exciting results coming from the early EMU observations. EMU is an incredibly ambitious project with scientific goals that range from understanding star and galaxy evolution to cosmological measurements of dark matter and dark energy, and much more. The discoveries from this early work demonstrate the power of the ASKAP telescope to deliver sensitive images over wide areas of sky, offering a tantalising glimpse of what the full EMU survey may reveal. This investigation has been critical in allowing us to design the main survey, which we expect will start in early 2022.”

    ASKAP is owned by the Commonwealth Scientific and Industrial Research Organisation (CSIRO). ASKAP is an array of 36 dish antennas with a largest separation of six kilometres, which when combined act like a telescope that is about 4000 square metres in size.

    ASKAP employs a novel technique called phased array feeds (PAF), and each of the 36 antennas has a PAF that allow the telescope to look at the sky in 36 directions at once, increasing the amount of sky that can be observed at once to 30 square degrees on the sky and thus, increasing survey speed.

    ASKAP is a precursor to the SKA, the world’s largest radio telescope, which is currently being built in South Africa and Australia, and is headquartered at the Jodrell Bank Observatory near Manchester, UK.

    See the full article here .

    Please help promote STEM in your local schools.

    Stem Education Coalition

    University of Keele (UK) is situated on an estate with extensive woods, lakes and parkland, formerly owned by the Sneyd family.

    The Sneyds came into possession of the Keele estate in the mid-16th century. Before the Sneyds the area was owned by the Knights Templar, a medieval Military Order. The first Keele Hall was built in 1580 and it was rebuilt in 1860. The Hall is a major conference, wedding and banqueting venue and has Grade II listing from English Heritage for its architectural importance.

    The University itself was founded as the University College of North Staffordshire in 1949 and received its Charter as the University of Keele in 1962.

     
  • richardmitnick 7:40 pm on August 18, 2021 Permalink | Reply
    Tags: "Most detailed-ever images of galaxies revealed using LOFAR", , , , , Radio Astronomy,   

    From Netherlands Institute for Radio Astronomy (ASTRON) (NL) : “Most detailed-ever images of galaxies revealed using LOFAR” 

    ASTRON bloc

    From Netherlands Institute for Radio Astronomy (ASTRON) (NL)

    17 August 2021

    After almost a decade of work, an international team of astronomers has published the most detailed images yet seen of galaxies beyond our own, revealing their inner workings in unprecedented detail. The images were created from data collected by the Low Frequency Array (LOFAR) [below], a radio telescope built and maintained by ASTRON, LOFAR is a network of more than 70,000 small antennae spread across nine European countries [see map below], with its core in Exloo, the Netherlands. The results come from the team’s years of work, led by Dr Leah Morabito at Durham University (UK). The team was supported by the Science and Technology Facilities Council (STFC) (UK).

    As well as supporting science exploitation, STFC also funds the UK subscription to LOFAR including upgrade costs and operation of its LOFAR station in Hampshire.

    Revealing a hidden universe of light in HD

    The universe is awash with electromagnetic radiation, of which visible light comprises just the tiniest slice. From short-wavelength gamma rays and X-rays, to long-wavelength microwave and radio waves, each part of the light spectrum reveals something unique about the universe.

    The LOFAR network captures images at FM radio frequencies that, unlike shorter wavelength sources like visible light, are not blocked by the clouds of dust and gas that can cover astronomical objects. Regions of space that seem dark to our eyes, actually burn brightly in radio waves – allowing astronomers to peer into star-forming regions or into the heart of galaxies themselves.

    The new images, made possible because of the international nature of the collaboration, push the boundaries of what we know about galaxies and super-massive black holes. A special issue of the scientific journal Astronomy & Astrophysics is dedicated to 11 research papers describing these images and the scientific results.

    2
    A compilation of the science results. Credit from left to right starting at the top: N. Ramírez-Olivencia et el. [radio]- National Aeronautics Space Agency (US), European Space Agency [Agence spatiale européenne][Europäische Weltraumorganisation](EU), the Hubble Heritage Team (Space Telescope Science Institute (US)/Assocation of Universities for Research in Astronomy (US))-ESA/Hubble Collaboration and A. Evans (The University of Virginia (US), Charlottesville /National Radio Astronomy Observatory (US)/Stony Brook University-SUNY (US)); edited by R. Cumming [optical], C. Groeneveld, R. Timmerman-LOFAR & NASA/ESA Hubble,. Kukreti- LOFAR & Sloan Digital Sky Survey (US), A. Kappes, F. Sweijen- LOFAR & DESI Legacy Imaging Survey; S. Badole- NASA, ESA L. Calcada; Graphics: W.L. Williams.

    Better resolution by working together

    The images reveal the inner-workings of nearby and distant galaxies at a resolution 20 times sharper than typical LOFAR images. This was made possible by the unique way the team made use of the array.

    The 70,000+ LOFAR antennae are spread across Europe, with the majority being located in the Netherlands. In standard operation, only the signals from antennae located in the Netherlands are combined, and creates a ‘virtual’ telescope with a collecting ‘lens’ with a diameter of 120 km. By using the signals from all of the European antennae, the team have increased the diameter of the ‘lens’ to almost 2,000 km, which provides a twenty-fold increase in resolution.

    Unlike conventional array antennae that combine multiple signals in real time to produce images, LOFAR uses a new concept where the signals collected by each antenna are digitised, transported to central processor, and then combined to create an image. Each LOFAR image is the result of combining the signals from more than 70,000 antennae, which is what makes their extraordinary resolution possible.

    3
    This shows real radio galaxies from Morabito et al. (2021). The gif fades from the standard resolution to the high resolution, showing the detail we can see by using the new techniques. Credit: L.K. Morabito-LOFAR Surveys KSP.

    Revealing jets and outflows from super-massive black holes.

    Super-massive black holes can be found lurking at the heart of many galaxies and many of these are ‘active’ black holes that devour in-falling matter and belch it back out into the cosmos as powerful jets and outflows of radiation. These jets are invisible to the naked eye, but they burn bright in radio waves and it is these that the new high-resolution images have focused upon.

    Dr Neal Jackson of The University of Manchester (UK), said: “These high resolution images allow us to zoom in to see what’s really going on when super-massive black holes launch radio jets, which wasn’t possible before at frequencies near the FM radio band,”

    The team’s work forms the basis of nine scientific studies that reveal new information on the inner structure of radio jets in a variety of different galaxies.

    4
    Hercules A is powered by a supermassive black hole located at its centre, which feeds on the surrounding gas and channels some of this gas into extremely fast jets. Our new high-resolutions observations taken with LOFAR have revealed that this jet grows stronger and weaker every few hundred thousand years. This variability produces the beautiful structures seen in the giant lobes, each of which is about as large as the Milky Way galaxy. Credit: R. Timmerman-LOFAR & Hubble Space Telescope.

    A decade-long challenge

    Even before LOFAR started operations in 2012, the European team of astronomers began working to address the colossal challenge of combining the signals from more than 70,000 antennae located as much as 2,000 km apart. The result, a publicly-available data-processing pipeline, which is described in detail in one the scientific papers, will allow astronomers from around the world to use LOFAR to make high-resolution images with relative ease.

    Dr Leah Morabito of Durham University, said: “Our aim is that this allows the scientific community to use the whole European network of LOFAR telescopes for their own science, without having to spend years to become an expert.”
    Super images require supercomputers

    The relative ease of the experience for the end user belies the complexity of the computational challenge that makes each image possible. Because LOFAR doesn’t just ‘take pictures’ of the night sky, it must stitch together the data gathered by more than 70,000 antennae, which is a huge computational task. To produce a single image, more than 13 terabits of raw data per second – the equivalent of more than a three hundred DVDs – must be digitised, transported to a central processor and then combined.

    Frits Sweijen of Leiden University [Universiteit Leiden] (NL), said: “To process such immense data volumes we have to use supercomputers. These allow us to transform the terabytes of information from these antennas into just a few gigabytes of science-ready data, in only a couple of days.”

    All images and video’s belonging to this press release can be found in high resolution here.

    See the full article here .

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    ASTRON is the ASTRON-Netherlands Institute for Radio Astronomy [Nederlands Instituut voor Radioastronomie] (NL). Its main office is in Dwingeloo in the Dwingelderveld National Park in the province of Drenthe. ASTRON is part of Netherlands Organisation for Scientific Research (NWO).

    ASTRON’s main mission is to make discoveries in radio astronomy happen, via the development of new and innovative technologies, the operation of world-class radio astronomy facilities, and the pursuit of fundamental astronomical research. Engineers and astronomers at ASTRON have an outstanding international reputation for novel technology development, and fundamental research in galactic and extra-galactic astronomy. Its main funding comes from NWO.

    ASTRON’s programme has three principal elements:

    The operation of front line observing facilities, including especially the Westerbork Synthesis Radio Telescope and LOFAR,
    The pursuit of fundamental astronomical research using ASTRON facilities, together with a broad range of other telescopes around the world and space-borne instruments (e.g. Sptizer, HST etc.)
    A strong technology development programme, encompassing both innovative instrumentation for existing telescopes and the new technologies needed for future facilities.

    In addition, ASTRON is active in the international science policy arena and is one of the leaders in the international SKA project. The Square Kilometre Array will be the world’s largest and most sensitive radio telescope with a total collecting area of approximately one square kilometre. The SKA will be built in Southern Africa and in Australia. It is a global enterprise bringing together 11 countries from the 5 continents.

    Radio telescopes

    ASTRON operates the Westerbork Synthesis Radio Telescope (WSRT), one of the largest radio telescopes in the world. The WSRT and the International LOFAR Telescope (ILT) are dedicated to explore the universe at radio frequencies ranging from 10 MHz to 8 GHz.

    In addition to its use as a stand-alone radio telescope, the Westerbork array participates in the European Very Long Baseline Interferometry Network (EVN) of radio telescopes.

    ASTRON is the host institute for the Joint Institute for VLBI in Europe (JIVE).

    Its primary task is to operate the EVN MkIV VLBI Data Processor (correlator). JIVE also provides a high-level of support to astronomers and the Telescope Network. ASTRON also hosts the NOVA Optical/ Infrared instrumentation group.

    LOFAR is a radio telescope composed of an international network of antenna stations and is designed to observe the universe at frequencies between 10 and 250 MHz. Operated by ASTRON (NL), the network includes stations in the Netherlands, Germany, Sweden, the U.K., France, Poland and Ireland.

     
  • richardmitnick 9:43 pm on August 17, 2021 Permalink | Reply
    Tags: "Reweighing A Heavy Neutron Star", , , , , Pulsar PSR J0740+6620, Radio Astronomy   

    From AAS NOVA : “Reweighing A Heavy Neutron Star” 

    AASNOVA

    From AAS NOVA

    16 August 2021
    Susanna Kohler

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    Artist’s impression of how the pulses emitted by the pulsar PSR J0740+6620 are affected by the gravity of its white-dwarf companion. Credit: B. Saxton/National Radio Astronomy Observatory (US)/Associated Universities Inc (US)

    What does the inside of a neutron star — the incredibly dense remnant of an evolved star — look like? New observations of one of the most massive neutron stars provide some clues.

    Mysterious Interior

    With the mass of multiple Suns packed into the rough size of a city, neutron stars represent one of the most dense, exotic environments in the universe. We can’t create an equivalent environment on Earth, so we rely on theoretical models — constrained by observations — to understand how matter behaves under these extreme circumstances.

    Different theoretical models predict different interior structures for neutron stars, each described by an equation of state. In turn, each equation of state predicts a different maximum mass that a neutron star can reach before the overwhelming crush of gravity causes it to collapse into a black hole.

    The heaviest neutron stars we spot in the universe, then, can help us to set upper limits and rule out some equations of state, narrowing down which models of neutron star interiors are most likely.

    The catch? Measuring the precise masses of objects located thousands of light-years away is difficult! Luckily, the universe occasionally offers up clever tricks for doing so.

    A Delay from Gravity

    Some highly magnetized neutron stars emit beams of light that regularly pulse across our line of sight as they rotate. If these incredibly precise cosmic clocks — pulsars — have a binary companion, and if we view that binary edge-on, then we have a unique opportunity for some mass measurements.

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

    In such a system, the distortion of spacetime caused by the gravity of the companion object can affect the signal of the pulsar, such that the pulses arrive at Earth at slightly offset times. This effect, known as the Shapiro time delay, allows us to precisely measure the companion’s mass — which can then be used with the binary orbit to establish the pulsar’s mass.

    In a recent study, a team of scientists led by Emmanuel Fonseca (McGill University (CA); West Virginia University (US)) have now used this approach with new observations of the pulsar PSR J0740+6620 to place the tightest constraints on its mass yet — and it’s a doozy.

    Tipping the Scales

    Fonseca and collaborators use observations from the 100-m Green Bank Telescope and the Canadian Hydrogen Intensity Mapping Experiment (CHIME) telescope to carefully model the Shapiro delay and measure the properties of PSR J0740+6620 and its companion, significantly improving upon previous measurements.

    Green Bank Radio Telescope, West Virginia, USA, now the center piece of the Green Bank Observatory(US), being cut loose by the National Science Foundation(US), supported by Breakthrough Listen Project, West Virginia University, and operated by the nonprofit Associated Universities, Inc..

    The authors show that PSR J0740+6620 weighs in at 2.01–2.15 solar masses — confirming its status as the heaviest precisely measured neutron star currently known. They also confirm that the binary lies ~3,700 light-years away, and that the companion is an unusually cold white dwarf of just 0.25 solar mass.

    Even more precise constraints — both on PSR J0740+6620 and other high-mass neutron stars — will be enabled by ongoing observations with currently technology, and by future studies using next-generation telescopes. Each improvement brings us a little closer to understanding the matter in these extreme objects.

    Citation

    “Refined Mass and Geometric Measurements of the High-mass PSR J0740+6620,” E. Fonseca et al 2021 ApJL 915 L12.

    https://iopscience.iop.org/article/10.3847/2041-8213/ac03b8

    See the full article here .


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    1

    AAS Mission and Vision Statement

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

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

    Adopted June 7, 2009

    The society was founded in 1899 through the efforts of George Ellery Hale. The constitution of the group was written by Hale, George Comstock, Edward Morley, Simon Newcomb and Edward Charles Pickering. These men, plus four others, were the first Executive Council of the society; Newcomb was the first president. The initial membership was 114. The AAS name of the society was not finally decided until 1915, previously it was the “Astronomical and Astrophysical Society of America”. One proposed name that preceded this interim name was “American Astrophysical Society”.

    The AAS today has over 7,000 members and six divisions – the Division for Planetary Sciences (1968); the Division on Dynamical Astronomy (1969); the High Energy Astrophysics Division (1969); the Solar Physics Division (1969); the Historical Astronomy Division (1980); and the Laboratory Astrophysics Division (2012). The membership includes physicists, mathematicians, geologists, engineers and others whose research interests lie within the broad spectrum of subjects now comprising contemporary astronomy.

    In 2019 three AAS members were selected into the tenth anniversary class of TED Fellows.

    The AAS established the AAS Fellows program in 2019 to “confer recognition upon AAS members for achievement and extraordinary service to the field of astronomy and the American Astronomical Society.” The inaugural class was designated by the AAS Board of Trustees and includes an initial group of 232 Legacy Fellows.

     
  • richardmitnick 1:14 pm on August 17, 2021 Permalink | Reply
    Tags: , , , , , , Radio Astronomy,   

    From National Aeronautics and Space Administration (US) Chandra X-ray Telescope (US): “Abell 1775-Chandra Catches Slingshot During Collision” 

    NASA Chandra Banner

    From National Aeronautics and Space Administration (US) Chandra X-ray Telescope (US)

    Abell 1775 is a system where a smaller galaxy cluster has plowed into a larger one.

    Using X-rays from Chandra and data from other telescopes astronomers are piecing together details of this collision.

    Features in the data, including a curving tail of hot gas and a “cold front”, are clues.

    Scientists will likely need more observations and modeling to get the full picture of Abell 1775.

    1
    Composite

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    X-ray

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    Optical/Infrared

    4
    Radio

    When the titans of space — galaxy clusters — collide, extraordinary things can happen. A new study using NASA’s Chandra X-ray Observatory examines the repercussions after two galaxy clusters clashed.

    Galaxy clusters are the largest structures in the Universe held together by gravity, containing hundreds or even thousands of individual galaxies immersed in giant oceans of superheated gas.

    In galaxy clusters, the normal matter — like the atoms that make up the stars, planets, and everything on Earth — is primarily in the form of hot gas and stars. The mass of the hot gas between the galaxies is far greater than the mass of the stars in all of the galaxies. This normal matter is bound in the cluster by the gravity of an even greater mass of dark matter.

    Because of the huge masses and speeds involved, collisions and mergers between galaxy clusters are among the most energetic events in the Universe.

    In a new study of the galaxy cluster Abell 1775, located about 960 million light years from Earth, a team of astronomers led by Andrea Botteon from Leiden University [Universiteit Leiden] (NL) in the Netherlands announced that they found a spiral-shaped pattern in Chandra’s X-ray data. These results imply a turbulent past for the cluster.

    When two galaxy clusters of different sizes have a grazing collision, the smaller cluster will begin to plow through the larger one. (Because of its superior mass, the bigger cluster has the upper hand when it comes to gravitational pull.) As the smaller cluster moves through, its hot gas is stripped off due to friction. This leaves behind a wake, or tail, that trails behind the cluster. After the center of the smaller cluster passes by the center of the larger one, the gas in the tail starts to encounter less resistance and overshoots the center of its cluster. This can cause the tail to “slingshot” as it flies to the side, curving as it extends away from the cluster’s center.

    The newest Chandra data contains evidence — including the brightness of the X-rays and the temperatures they represent — for one of these curving “slingshot” tails. Previous studies of Abell 1775 with Chandra and other telescopes hinted, but did not confirm, that there was an ongoing collision in this system.

    A new image of Abell 1775 contains X-rays from Chandra (blue), optical data from the Pan-STARRS telescope in Hawaii (blue, yellow, and white), and radio data from the LOw Frequency ARray (LOFAR) in the Netherlands (red).

    The tail is labeled in this image along with a region of gas with a curved edge, called a “cold front,” that is denser and cooler than the gas it is plowing into. The tail and the cold front all curve in the same direction, creating a spiral appearance. A separate labeled image shows the field of view of the Chandra data.

    Astronomers previously found that Abell 1775 contains an enormous jet and radio source, which is also seen in this new composite image. This jet is powered by a supermassive black hole in a large elliptical galaxy in the cluster’s center. New data from LOFAR and the Giant Metrewave Radio Telescope (GMRT) in India reveals that the radio jet is actually 2.6 million light years long.

    This is about twice as long as astronomers thought it was before and makes it one of the longest ever observed in a galaxy cluster. The structure of the jet changes abruptly as it crosses into the lower density gas in the upper part of the image, across the edge of the cold front, implying that the collision has affected it.

    According to the new study, the gas motions inside the cluster could be responsible for other structures detected by observing Abell 1775 in radio waves, such as two filaments located near the origin of the jet (one of these is labeled). The LOFAR and Chandra data have also enabled the researchers to study in great detail the phenomena that contribute to accelerating electrons both in this galaxy’s jet and in the radio emission near the center of the larger cluster.

    There is an alternate explanation for the appearance of the cluster. As a small cluster approaches a larger one, the dense hot gas of the larger cluster will be attracted to it by gravity. After the smaller cluster passes the center of the other cluster, the direction of motion of the cluster gas reverses, and it travels back towards the cluster center. The cluster gas moves through the center again and “sloshes” back and forth, similar to wine sloshing in a glass that was jerked sideways. The sloshing gas ends up in a spiral pattern because the collision between the two clusters was off-center.

    The Botteon team favors the slingshot tail scenario, but a separate group of astronomers led by Dan Hu of Shanghai Jiao Tong University [海交通大学](CN) in China favors the sloshing explanation based on data from Chandra and ESA’s XMM-Newton.

    Both the slingshot and sloshing scenarios involve a collision between two galaxy clusters. Eventually the two clusters will fully merge with each other to form a single, larger galaxy cluster.

    Further observations and modeling of Abell 1775 are required to help decide between these two scenarios.

    A paper describing the results by Botteon’s team has been published in the journal Astronomy & Astrophysics. The separate work on the “sloshing” theory led by Dan Hu has been accepted for publication in The Astrophysical Journal.


    Quick Look: Chandra Catches Slingshot During Collision.

    See the full article here .


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    NASA’s Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra’s science and flight operations from Cambridge, Mass.

    In 1976 the Chandra X-ray Observatory (called AXAF at the time) was proposed to National Aeronautics and Space Administration (US) by Riccardo Giacconi and Harvey Tananbaum. Preliminary work began the following year at NASA’s Marshall Space Flight Center(US) and the Harvard Smithsonian Center for Astrophysics(US) . In the meantime, in 1978, NASA launched the first imaging X-ray telescope, Einstein (HEAO-2), into orbit. Work continued on the AXAF project throughout the 1980s and 1990s. In 1992, to reduce costs, the spacecraft was redesigned. Four of the twelve planned mirrors were eliminated, as were two of the six scientific instruments. AXAF’s planned orbit was changed to an elliptical one, reaching one third of the way to the Moon’s at its farthest point. This eliminated the possibility of improvement or repair by the space shuttle but put the observatory above the Earth’s radiation belts for most of its orbit. AXAF was assembled and tested by TRW (now Northrop Grumman Aerospace Systems) in Redondo Beach, California.

    AXAF was renamed Chandra as part of a contest held by NASA in 1998, which drew more than 6,000 submissions worldwide. The contest winners, Jatila van der Veen and Tyrel Johnson (then a high school teacher and high school student, respectively), suggested the name in honor of Nobel Prize–winning Indian-American astrophysicist Subrahmanyan Chandrasekhar. He is known for his work in determining the maximum mass of white dwarf stars, leading to greater understanding of high energy astronomical phenomena such as neutron stars and black holes. Fittingly, the name Chandra means “moon” in Sanskrit.

    Originally scheduled to be launched in December 1998, the spacecraft was delayed several months, eventually being launched on July 23, 1999, at 04:31 UTC by Space Shuttle Columbia during STS-93. Chandra was deployed from Columbia at 11:47 UTC. The Inertial Upper Stage’s first stage motor ignited at 12:48 UTC, and after burning for 125 seconds and separating, the second stage ignited at 12:51 UTC and burned for 117 seconds. At 22,753 kilograms (50,162 lb), it was the heaviest payload ever launched by the shuttle, a consequence of the two-stage Inertial Upper Stage booster rocket system needed to transport the spacecraft to its high orbit.

    Chandra has been returning data since the month after it launched. It is operated by the SAO at the Chandra X-ray Center in Cambridge, Massachusetts, with assistance from Massachusetts Institute of Technology(US) and Northrop Grumman Space Technology. The ACIS CCDs suffered particle damage during early radiation belt passages. To prevent further damage, the instrument is now removed from the telescope’s focal plane during passages.

    Although Chandra was initially given an expected lifetime of 5 years, on September 4, 2001, NASA extended its lifetime to 10 years “based on the observatory’s outstanding results.” Physically Chandra could last much longer. A 2004 study performed at the Chandra X-ray Center indicated that the observatory could last at least 15 years.

    In July 2008, the International X-ray Observatory, a joint project between European Space Agency [Agence spatiale européenne][Europäische Weltraumorganisation](EU), NASA and Japan Aerospace Exploration Agency (JAXA) (国立研究開発法人宇宙航空研究開発機構], was proposed as the next major X-ray observatory but was later cancelled. ESA later resurrected a downsized version of the project as the Advanced Telescope for High Energy Astrophysics (ATHENA), with a proposed launch in 2028.

    European Space Agency [Agence spatiale européenne][Europäische Weltraumorganisation](EU) Athena spacecraft depiction

    On October 10, 2018, Chandra entered safe mode operations, due to a gyroscope glitch. NASA reported that all science instruments were safe. Within days, the 3-second error in data from one gyro was understood, and plans were made to return Chandra to full service. The gyroscope that experienced the glitch was placed in reserve and is otherwise healthy.

     
  • richardmitnick 9:48 am on August 10, 2021 Permalink | Reply
    Tags: "NSF Awards Funding for Next-Generation VLA Antenna Development", , , Construction could begin by 2026 with early scientific observations starting in 2029 and full scientific operations by 2035., , More far-flung antennas will be located in clusters in Hawaii; Washington; California; Iowa; West Virginia; New Hampshire; Puerto Rico (at Arecibo Observatory); the U.S. Virgin Islands; and Canada., , On May 27 NRAO officials signed an agreement with the firm mtex antenna technology Gmbh of Germany to develop a production-ready design and produce the prototype 18-meter antenna., Once built the 18-meter prototype will be installed at the site of NSF’s Karl G. Jansky Very Large Array (VLA) in west-central New Mexico., Radio Astronomy, The ngVLA will be a key tool for answering the important scientific questions facing astronomers in the coming decades., The ngVLA will have a dense core of antennas and a signal processing center at the current site of the VLA on the Plains of San Agustin in New Mexico., The ngVLA will have sensitivity to detect faint objects and resolving power — ability to see fine detail — more than 10 times greater than the current VLA., The ngVLA will include 244 antennas that are 18 meters (59 feet) in diameter with an additional 19 6-meter (20-foot) dishes at the center of the system., The ngVLA’s design is the result of extensive collaboration with researchers across the landscape of astrophysics., The system will include other antennas located throughout New Mexico and in west Texas; eastern Arizona; and northern Mexico.   

    From National Radio Astronomy Observatory (US) : “NSF Awards Funding for Next-Generation VLA Antenna Development” 

    NRAO Banner

    From National Radio Astronomy Observatory (US)

    August 9, 2021

    Dave Finley, Public Information Officer
    (505) 241-9210
    dfinley@nrao.edu

    1
    Credit: Sophia Dagnello, NRAO/Associated Universities Inc (US)/National Science Foundation (US).

    The National Science Foundation (NSF) has awarded the National Radio Astronomy Observatory (NRAO) $23 million for design and development work on the Next Generation Very Large Array (ngVLA), including producing a prototype antenna. The ngVLA, a powerful radio telescope with 263 dish antennas distributed across North America, is proposed as one of the next generation of cutting-edge astronomical observatories.

    “The ngVLA will be a key tool for answering the important scientific questions facing astronomers in the coming decades. We welcome this vital support for the next step — building the first antenna — toward making this exciting research facility a reality,” said NRAO Director Tony Beasley.

    The ngVLA will include 244 antennas that are 18 meters (59 feet) in diameter with an additional 19 6-meter (20-foot) dishes at the center of the system.

    The ngVLA project currently is under review by the Astronomy and Astrophysics Decadal Survey (Astro2020) of the National Academy of Sciences (US). That report is expected soon. Following that report, the project will need approval by the National Science Foundation’s National Science Board and funding by Congress. Construction could begin by 2026 with early scientific observations starting in 2029 and full scientific operations by 2035.

    “This exciting project marks the beginning of a new era, and major milestone, in antenna technology,” said Joseph Pesce, NRAO Program Officer at the NSF. “While we look forward to the results from the Astro2020 Decadal Survey in regard to ngVLA, we expect this is the antenna of the future and will be used well beyond any one project,” he added.

    On May 27 NRAO officials signed an agreement with the firm mtex antenna technology Gmbh of Germany to develop a production-ready design and produce the prototype 18-meter antenna. Once built the 18-meter prototype will be installed at the site of NSF’s Karl G. Jansky Very Large Array (VLA) in west-central New Mexico, where it will undergo extensive testing.

    Building on the scientific and technical legacies of the VLA and the Atacama Large Millimeter/submillimeter Array (ALMA), the ngVLA will have sensitivity to detect faint objects and resolving power — ability to see fine detail — more than 10 times greater than the current VLA. It is being designed to address fundamental questions in all major areas of astrophysics and provide a major leap forward in our understanding of phenomena such as planets, galaxies, black holes, and the dynamic sky. The ngVLA’s capabilities will complement those of ALMA and other planned instruments such as the lower-frequency Square Kilometer Array.

    “The ngVLA will fit neatly into a suite of current and planned observatories that will operate over the next decades, offering the entire astronomical community vital capabilities unmatched by any other telescope system,” said Mark McKinnon, ngVLA Project Director.

    “Strengthening New Mexico’s leadership in radio astronomy is going to take an ambitious vision. I am so pleased to see this funding positioned to help jumpstart the Next Generation Very Large Array project so that the National Radio Astronomy Observatory, with offices present at New Mexico Tech, can begin their work to enhance America’s world-renowned scientific research infrastructure across the U.S. – and right here in New Mexico. I will continue fighting for similar funding that creates career opportunities within New Mexico’s science community and keeps our state at the cutting edge of space research and technology,” said U.S. Senator Martin Heinrich (D-NM)

    “New Mexico is a national leader in innovation and scientific discovery, and I’m pleased to see the National Science Foundation supporting the design and development of NRAO’s Next Generation Very Large Array, a project that will foster further discoveries. As a new member of the Senate Committee on Commerce, Science, and Transportation, I’ll continue working to secure strong investments that shore up our state’s science and technology economy,” said U.S Senator Ben Ray Luján (D-NM)

    “I am excited to see the National Science Foundation has awarded funding to develop the Next Generation Very Large Array,” said Congresswoman Yvette Herrell (R-NM). “This new radio telescope, parts of which will be located right here in New Mexico, will be instrumental in gaining a better understanding of our universe. I am proud New Mexico will be at the forefront of this innovative advancement in the field of astronomy.”

    The ngVLA will have a dense core of antennas and a signal processing center at the current site of the VLA on the Plains of San Agustin in New Mexico. The system will include other antennas located throughout New Mexico and in west Texas; eastern Arizona; and northern Mexico. More far-flung antennas will be located in clusters in Hawaii; Washington; California; Iowa; West Virginia; New Hampshire; Puerto Rico (at Arecibo Observatory); the U.S. Virgin Islands; and Canada. Operations will be conducted at the VLA site and in nearby Socorro, New Mexico, with additional science operations in a metropolitan area to be determined.

    The ngVLA’s design is the result of extensive collaboration with researchers across the landscape of astrophysics. Through a series of workshops and science meetings beginning in 2015, NRAO worked with numerous scientists and engineers to develop a design that will support a wide breadth of scientific investigations over the lifetime of the facility. Participants from around the world contributed suggestions and expertise that helped guide the design.

    “We heard from many of our scientific colleagues about how they want to use such a next-generation radio telescope, and worked hard to build a consensus on its capabilities to support their needs. We continue to get valuable advice and support from those who serve on our ngVLA science and technical councils,” said Eric Murphy, NRAO’s Project Scientist for ngVLA.

    See the full article here .


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

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

    *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.

     
  • richardmitnick 3:42 pm on August 6, 2021 Permalink | Reply
    Tags: , , , , , , , NASA Psyche spacecraft, , , Psyche orbits the sun in the asteroid belt., Psyche's surface is no less than 30 percent metal., Radio Astronomy, , The asteroid Psyche, We've known for many years that objects in this class are not in fact solid metal but what they are and how they formed is still an enigma.   

    From California Institute of Technology (US) : “Observatory in Chile Takes Highest-Resolution Measurements of Asteroid Surface Temperatures Ever Obtained from Earth” 

    Caltech Logo

    From California Institute of Technology (US)

    August 05, 2021

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    The study’s target, Psyche, is the destination of an upcoming NASA mission.

    A close examination of the millimeter-wavelength emissions from the asteroid Psyche, which NASA intends to visit in 2026, has produced the first temperature map of the object, providing new insight into its surface properties. The findings, described in a paper published in Planetary Science Journal on August 5, are a step toward resolving the mystery of the origin of this unusual object, which has been thought by some to be a chunk of the core of an ill-fated protoplanet.

    Psyche orbits the sun in the asteroid belt, a donut-shaped region of space between Earth and Jupiter that contains more than a million rocky bodies that range in size from 10 meters to 946 kilometers in diameter.

    With a diameter of more than 200 km, Psyche is the largest of the M-Type asteroids, an enigmatic class of asteroids that are thought to be metal rich and therefore potentially may be fragments of the cores of proto-planets that broke up as the solar system formed.

    “The early solar system was a violent place, as planetary bodies coalesced and then collided with one another while settling into orbits around the sun,” says Caltech’s Katherine de Kleer, assistant professor of planetary science and astronomy and lead author of the PSJ article. “We think that fragments of the cores, mantles, and crusts of these objects remain today in the form of asteroids. If that’s true, it gives us our only real opportunity to directly study the cores of planet-like objects.”

    Studying such relatively tiny objects that are so far away from Earth (Psyche drifts at a distance that ranges between 179.5 and 329 million km from Earth) poses a significant challenge to planetary scientists, which is why NASA plans to send a probe to Psyche to examine it up close.

    Typically, thermal observations from Earth—which measure the light emitted by an object itself rather than light from the sun reflected off of that object—are in infrared wavelengths and can produce only 1-pixel images of asteroids. That one pixel does, however, reveal a lot of information; for example, it can be used to study the asteroid’s thermal inertia, or how fast it heats up in sunlight and cools down in darkness.

    “Low thermal inertia is typically associated with layers of dust, while high thermal inertia may indicate rocks on the surface,” says Caltech’s Saverio Cambioni, postdoctoral scholar in planetary science and co-author of the PSJ article. “However, discerning one type of landscape from the other is difficult.” Data from viewing each surface location at many times of day provide much more detail, leading to an interpretation that is subject to less ambiguity, and which provide a more reliable prediction of landscape type prior to a spacecraft’s arrival.

    De Kleer and Cambioni, together with co-author Michael Shepard of Bloomsburg University (US) in Pennsylvania, took advantage of the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, which became fully operational in 2013, to obtain such data.

    The array of 66 radio telescopes enabled the team to map the thermal emissions from Psyche’s entire surface at a resolution of 30 km (where each pixel is 30 km by 30 km) and generate an image of the asteroid composed of about 50 pixels.

    This was possible because ALMA observed Psyche at millimeter wavelengths, which are longer (ranging from 1 to 10 millimeters) than the infrared wavelengths (typically between 5 and 30 microns). The use of longer wavelengths allowed the researchers to combine the data collected from the 66 telescopes to create a much larger effective telescope; the larger a telescope, the higher the resolution of the images it produces.

    The study confirmed that Psyche’s thermal inertia is high compared to that of a typical asteroid, indicating that Psyche has an unusually dense or conductive surface. When de Kleer, Cambioni, and Shepard analyzed the data, they also found that Psyche’s thermal emission—the amount of heat it radiates—is just 60 percent of what would be expected from a typical surface with that thermal inertia. Because surface emission is affected by the presence of metal on the surface, their finding indicates that Psyche’s surface is no less than 30 percent metal. An analysis of the polarization of the emission helped the researchers to roughly determine what form that metal takes. A smooth solid surface emits well-organized polarized light; the light emitted by Psyche, however, was scattered, suggesting that rocks on the surface are peppered with metallic grains.

    “We’ve known for many years that objects in this class are not in fact solid metal but what they are and how they formed is still an enigma,” de Kleer says. The findings reinforce alternative proposals for Psyche’s surface composition, including that Psyche could be a primitive asteroid that formed closer to the sun than it is today instead of a core of a fragmented protoplanet.

    The techniques described in this study provide a new perspective on asteroid surface compositions. The team is now expanding its scope to apply these techniques to other large objects in the asteroid belt.

    The study was enabled by a related project by the team led by Michael Shepard at Bloomsburg University that utilized de Kleer’s data in combination with data from other telescopes, including Arecibo Observatory in Puerto Rico, to pin down the size, shape, and orientation of Psyche. That in turn allowed the researchers to determine which pixels that had been captured actually represented the asteroid’s surface. Shepard’s team was scheduled to observe Psyche again at the end of 2020, but damage from cable failures shut the telescope down before the observations could be made.

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Caltech campus

    The California Institute of Technology (US) is a private research university in Pasadena, California. The university is known for its strength in science and engineering, and is one among a small group of institutes of technology in the United States which is primarily devoted to the instruction of pure and applied sciences.

    Caltech was founded as a preparatory and vocational school by Amos G. Throop in 1891 and began attracting influential scientists such as George Ellery Hale, Arthur Amos Noyes, and Robert Andrews Millikan in the early 20th century. The vocational and preparatory schools were disbanded and spun off in 1910 and the college assumed its present name in 1920. In 1934, Caltech was elected to the Association of American Universities, and the antecedents of National Aeronautics and Space Administration (US)’s Jet Propulsion Laboratory, which Caltech continues to manage and operate, were established between 1936 and 1943 under Theodore von Kármán.

    Caltech has six academic divisions with strong emphasis on science and engineering. Its 124-acre (50 ha) primary campus is located approximately 11 mi (18 km) northeast of downtown Los Angeles. First-year students are required to live on campus, and 95% of undergraduates remain in the on-campus House System at Caltech. Although Caltech has a strong tradition of practical jokes and pranks, student life is governed by an honor code which allows faculty to assign take-home examinations. The Caltech Beavers compete in 13 intercollegiate sports in the NCAA Division III’s Southern California Intercollegiate Athletic Conference (SCIAC).

    As of October 2020, there are 76 Nobel laureates who have been affiliated with Caltech, including 40 alumni and faculty members (41 prizes, with chemist Linus Pauling being the only individual in history to win two unshared prizes). In addition, 4 Fields Medalists and 6 Turing Award winners have been affiliated with Caltech. There are 8 Crafoord Laureates and 56 non-emeritus faculty members (as well as many emeritus faculty members) who have been elected to one of the United States National Academies. Four Chief Scientists of the U.S. Air Force and 71 have won the United States National Medal of Science or Technology. Numerous faculty members are associated with the Howard Hughes Medical Institute(US) as well as National Aeronautics and Space Administration(US). According to a 2015 Pomona College(US) study, Caltech ranked number one in the U.S. for the percentage of its graduates who go on to earn a PhD.

    Research

    Caltech is classified among “R1: Doctoral Universities – Very High Research Activity”. Caltech was elected to the Association of American Universities in 1934 and remains a research university with “very high” research activity, primarily in STEM fields. The largest federal agencies contributing to research are National Aeronautics and Space Administration(US); National Science Foundation(US); Department of Health and Human Services(US); Department of Defense(US), and Department of Energy(US).

    In 2005, Caltech had 739,000 square feet (68,700 m^2) dedicated to research: 330,000 square feet (30,700 m^2) to physical sciences, 163,000 square feet (15,100 m^2) to engineering, and 160,000 square feet (14,900 m^2) to biological sciences.

    In addition to managing JPL, Caltech also operates the Caltech Palomar Observatory(US); the Owens Valley Radio Observatory(US);the Caltech Submillimeter Observatory(US); the W. M. Keck Observatory at the Mauna Kea Observatory(US); the Laser Interferometer Gravitational-Wave Observatory at Livingston, Louisiana and Richland, Washington; and Kerckhoff Marine Laboratory(US) in Corona del Mar, California. The Institute launched the Kavli Nanoscience Institute at Caltech in 2006; the Keck Institute for Space Studies in 2008; and is also the current home for the Einstein Papers Project. The Spitzer Science Center(US), part of the Infrared Processing and Analysis Center(US) located on the Caltech campus, is the data analysis and community support center for NASA’s Spitzer Infrared Space Telescope [no longer in service].

    Caltech partnered with University of California at Los Angeles(US) to establish a Joint Center for Translational Medicine (UCLA-Caltech JCTM), which conducts experimental research into clinical applications, including the diagnosis and treatment of diseases such as cancer.

    Caltech operates several Total Carbon Column Observing Network(US) stations as part of an international collaborative effort of measuring greenhouse gases globally. One station is on campus.

     
  • richardmitnick 9:59 am on August 6, 2021 Permalink | Reply
    Tags: "Astronomers Detected a Huge New Structure in The Milky Way And Don't Know What It Is", A newly discovered astronomical structure named the "Cattail", , , , , Nanjing University [南京大學] (CN), Radio Astronomy, ,   

    From Nanjing University [南京大學] (CN) via Science Alert (US) : “Astronomers Detected a Huge New Structure in The Milky Way And Don’t Know What It Is” 

    From Nanjing University [南京大學] (CN)

    via

    ScienceAlert

    Science Alert (US)

    6 AUGUST 2021
    MICHELLE STARR

    1
    Artist’s impression of the Milky Way galaxy. (Mark Garlick/Science Photo Library/Getty Images)

    When you’re swimming in a large body of water, calculating its volume or discerning the locations of distant floating objects isn’t easy. The same is true for our galaxy.

    From our position inside the Milky Way, much of its size, contents, and three-dimensional structure is really tricky to figure out. There’s a lot that eludes us, or is impossible to calculate; even so, every now and again, a discovery comes along that makes you wonder, how in the heck did we miss that?!

    A newly discovered structure named the “Cattail” is just such a wonder. It’s a long curl of gas that’s so large, astronomers aren’t sure whether or not it might actually be part of a galactic spiral arm that we never noticed until now.

    Even if it isn’t the sign of an unmapped spiral arm, the “Cattail” may be the largest filament of gas in our galaxy discovered to date. It’s been described in a paper accepted to The Astrophysical Journal Letters.

    The structure “appears to be so far the furthest and largest giant filament in the galaxy,” a team of astronomers from Nanjing University [南京大學] (CN) writes in the paper.

    “The question about how such a huge filament is produced at the extreme galactic location remains open. Alternatively, “Cattail” might be part of a new arm … though it is puzzling that the structure does not fully follow the warp of the galactic disk.”

    There are several reasons it’s hard to map the Milky Way in three dimensions. One of them is that it’s very tricky to work out the distances to cosmic objects. Another is that there is a lot of stuff out there, so it can be hard to know if something is a significant grouping or just a random collection spread out along a line of sight.

    To identify the “Cattail”, a team led by Nanjing University astronomer Chong Li used the huge Five-hundred-meter Aperture Spherical radio Telescope (FAST) to look for clouds of neutral atomic hydrogen (HI).

    Such clouds are usually found in the spiral arms of galaxies like ours; by studying subtle differences in the hydrogen’s light, it’s possible to map the number and arrangement of the Milky Way’s arms from within.

    In August 2019, the researchers used FAST to look for HI radio emissions, and the data revealed what appeared to be a large structure. When they calculated how fast the structure was moving, they got a surprise: its velocity was consistent with a distance of around 71,750 light-years from the galactic center – the outer regions of the galaxy.

    That distance – farther than any known spiral arms in that region of the galaxy – would mean the thing is absolutely huge, with a size of around 3,590 light-years in length and 675 light-years in width, based on the FAST data.

    But then, when the researchers combined their findings with data from the HI4PI all-sky HI survey, they found that it could be even larger still – as much as around 16,300 light-years in length.

    That would make it even more colossal than the gas structure known as “Gould’s Belt”, which was recently found to be 9,000 light-years long.

    2
    Credit: Alyssa Goodman/WorldWide Telescope.

    3
    A ribbon of ammonia — a tracer of star-forming gas — in the Orion Molecular Cloud as seen with the GBT (orange); background in blue is an infrared image from NASA’s WISE telescope showing the dust in the region.

    Image credit: R. Friesen, U Toronto Dunlap Institute for Astronomy and Astrophysics (CA) / J. Pineda, MPG Institute for Astrophysics [MPG Institut für Astrophysik](DE)/ Green Bank Observatory (US) /Associated Universities Inc (US) / National Science Foundation (US) / National Aeronautics Space Agency (US).
    Rachel K. Friesen et al. 2017. The Green Bank Ammonia Survey (GAS): First Results of NH3 mapping the “Gould Belt”.

    The “Cattail” raises some interesting questions. Most gas filaments occur much closer to the galactic center, and are associated with spiral arms. If it’s a filament, it’s unclear how the “Cattail” could have formed and remained out beyond the known spiral arms of the Milky Way.

    On the other hand, if it’s a spiral arm, that’s also peculiar. The galactic disc of the Milky Way is wobbly and warped from an encounter with another galaxy, a long time ago. Yet the “Cattail’s” shape does not entirely conform to this warp – which it should do if it was a spiral arm.

    Even if the discovery wasn’t already fascinating, these peculiarities indicate that we might want to take a closer look at this amazing structure.

    “While these questions remain open with the existing data,” the researchers wrote, “the observations provide new insights into our understanding of the galactic structure.”

    The research has been accepted into The Astrophysical Journal Letters.

    See the full article here .


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    Please help promote STEM in your local schools.


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