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  • richardmitnick 5:05 pm on September 17, 2018 Permalink | Reply
    Tags: DU-Discover the Universe program, Dunlap Institute for Astronomy and Astrophysics, NSERC-National Sciences & Engineering Research Council of Canada, PromoScience Program,   

    From Dunlap Institute for Astronomy and Astrophysics: “New Funding Helps U Of T Astronomers Help Students Discover The Universe” 

    Dunlap Institute bloc
    From Dunlap Institute for Astronomy and Astrophysics

    At U Toronto

    1

    Sept. 17, 2018

    Julie Bolduc-Duval
    Discover the Universe
    e: julie.bolduc-duval@dunlap.utoronto.ca
    p: 418-332-0428

    Professor Michael Reid
    Public Outreach Coordinator
    Dunlap Institute for Astronomy & Astrophysics
    University of Toronto
    e: mike.reid@utoronto.ca
    p: 416-978-0307Dunlap

    The Dunlap Institute’s Discover the Universe program has been awarded significant financial support from the PromoScience Program of the National Sciences & Engineering Research Council of Canada (NSERC).

    Discover the Universe (DU) provides instruction and resources, in French and English, that help science teachers across the country and around the world teach astronomy to their students. DU provides astronomy teaching support through live workshops, webinars and teaching resources for teachers.

    “Astronomy is a vast subject and it is intimidating to teach it when you have no training in the field,” says Julie Bolduc-Duval, who founded DU in 2011 with financial support from PromoScience. “That’s why we created Discover the Universe. We’re helping teachers so that more kids will be exposed to our wonderful Universe and understand our place within it.”

    DU is offered by the Dunlap Institute for Astronomy & Astrophysics, University of Toronto, and the Canadian Astronomical Society, in collaboration with the Centre for Research in Astrophysics of Quebec.

    According to Professor Michael Reid, Outreach Coordinator for the Dunlap Institute of Astronomy & Astrophysics, University of Toronto, “The Dunlap’s mission to share the thrill of astronomical discovery with people of all ages has made working with Discover the Universe a natural fit.”

    “We’re immensely grateful to NSERC,” says Reid, “without whom we wouldn’t be able to keep delivering innovative, bilingual teacher training to teachers across Canada and around the world. This funding will help ensure that thousands of Canadian kids have eye-opening encounters with the cosmos that we know can inspire them to pursue careers in STEM.”

    PromoScience is a NSERC program that offers financial support for organizations that promote an understanding of science, engineering, mathematics and technology in young Canadians. The newly announced award to DU includes funding for three years.

    Visit the Discover the Universe website.

    Visit the NSERC PromoScience program website.

    See the full article here .


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Dunlap Institute campus

    The Dunlap Institute is committed to sharing astronomical discovery with the public. Through lectures, the web, social and new media, an interactive planetarium, and major events like the Toronto Science Festival, we are helping to answer the public’s questions about the Universe.
    Our work is greatly enhanced through collaborations with the Department of Astronomy & Astrophysics, Canadian Institute for Theoretical Astrophysics, David Dunlap Observatory, Ontario Science Centre, Royal Astronomical Society of Canada, the Toronto Public Library, and many other partners.

     
  • richardmitnick 3:21 pm on June 29, 2018 Permalink | Reply
    Tags: , , , , Dunlap Institute for Astronomy and Astrophysics,   

    From Dunlap Institute for Astronomy and Astrophysics: “Astronomers Observe the Magnetic Field of the Remains of Supernova 1987A” 

    Dunlap Institute bloc
    From Dunlap Institute for Astronomy and Astrophysics

    6.29.18

    CONTACT INFORMATION:

    Prof. Bryan Gaensler, Director
    Dunlap Institute for Astronomy & Astrophysics
    University of Toronto
    p: 416-978-6623
    e: bgaensler@dunlap.utoronto.ca
    w: dunlap.utoronto.ca

    Chris Sasaki
    Communications Coordinator | Press Officer
    Dunlap Institute for Astronomy & Astrophysics
    University of Toronto
    p: 416-978-6613
    e: csasaki@dunlap.utoronto.ca
    w: dunlap.utoronto.ca

    At U Toronto

    1
    This Hubble Space Telescope image of the remnant of Supernova 1987A shows a bright inner ring glowing as it interacts with material from the supernova blast. The ring is approximately one light-year in diameter. It is not clear what is causing the two larger, fainter rings. The two bright objects are stars in the Large Magellanic Cloud. The image was taken in 2010. Image: NASA, ESA, R. Kirshner and P. Challis (Harvard-Smithsonian Center for Astrophysics)

    NASA/ESA Hubble Telescope

    Large Magellanic Cloud. Adrian Pingstone December 2003

    For the first time, astronomers have directly observed the magnetism in one of astronomy’s most studied objects: the remains of Supernova 1987A (SN 1987A), a dying star that appeared in our skies over thirty years ago.

    In addition to being an impressive observational achievement, the detection provides insight into the early stages of the evolution of supernova remnants and the cosmic magnetism within them.

    “The magnetism we’ve detected is around 50,000 times weaker than a fridge magnet,” says Prof. Bryan Gaensler. “And we’ve been able to measure this from a distance of around 1.6 million trillion kilometres.”

    “This is the earliest possible detection of the magnetic field formed after the explosion of a massive star,” says Dr. Giovanna Zanardo.

    Gaensler is Director of the Dunlap Institute for Astronomy & Astrophysics at the University of Toronto, and a co-author on the paper announcing the discovery being published in The Astrophysical Journal Letters on June 29th. The lead author, Zanardo, and co-author Prof. Lister Staveley-Smith are both from the University of Western Australia’s node of the International Centre for Radio Astronomy Research.

    SN 1987A was co-discovered by University of Toronto astronomer Ian Shelton in February 1987 from the then Southern Observatory of the University of Toronto in northern Chile. It is located in the Large Magellanic Cloud, a dwarf galaxy companion to the Milky Way Galaxy, at a distance of 168,000 light-years from Earth. It was the first naked-eye supernova to be observed since the astronomer Johannes Kepler witnessed a supernova over 400 years ago.

    CSIRO Australia Compact Array, six radio telescopes at the Paul Wild Observatory, is an array of six 22-m antennas located about twenty five kilometres (16 mi) west of the town of Narrabri in Australia.

    In the thirty years since the supernova occurred, material expelled by the blast, as well as the shockwave from the star’s death throes, have been travelling outward through the gas and dust that surrounded the star before it exploded. Today, when we look at the remnant, we see rings of material set aglow by the supernova’s expanding debris and shockwave.

    Using the Australia Telescope Compact Array at the Paul Wild Observatory, Gaensler and his colleagues observed the magnetic field by studying the radiation coming from the object. By analyzing the properties of this radiation, they were able to trace the magnetic field.

    “The picture shows what it would look like if you could sprinkle iron filings over the expanding cloud of debris, 170 thousand light years away”, says Gaensler.

    3
    A map of the SN 1987A remnant with short orange lines showing the orientation of the magnetic field. Image: Giovanna Zanardo

    What they found was that the remnant’s magnetic field was not chaotic but already showed a degree of order. Astronomers have known that as supernova remnants get older, their magnetic fields are stretched and aligned into ordered patterns. So, the team’s observation showed that a supernova remnant can bring order to a magnetic field in the relatively short period of thirty years.

    The magnetic field lines of the Earth run north and south, causing a compass to point to the Earth’s poles. By comparison, the magnetic field lines associated with SN 1987A are like the spokes of a bicycle wheel aligned from the centre out.

    “At such a young age,” says Zanardo, “everything in the stellar remnant is moving incredibly fast and changing rapidly, but the magnetic field looks nicely combed out all the way to the edge of the shell.”

    Gaensler and his colleagues will continue to observe the constantly evolving remnant. “As it continues to expand and evolve,” says Gaensler, “we will be watching the shape of the magnetic field to see how it changes as the shock wave and debris cloud run into new material.”

    See the full article here .


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Dunlap Institute campus

    The Dunlap Institute is committed to sharing astronomical discovery with the public. Through lectures, the web, social and new media, an interactive planetarium, and major events like the Toronto Science Festival, we are helping to answer the public’s questions about the Universe.
    Our work is greatly enhanced through collaborations with the Department of Astronomy & Astrophysics, Canadian Institute for Theoretical Astrophysics, David Dunlap Observatory, Ontario Science Centre, Royal Astronomical Society of Canada, the Toronto Public Library, and many other partners.

     
  • richardmitnick 12:00 pm on May 24, 2018 Permalink | Reply
    Tags: , , , , Dunlap Institute for Astronomy and Astrophysics, Pulsar PSR B1957+20,   

    From Dunlap Institute for Astronomy and Astrophysics at U Toronto: “Astronomers Observe Unprecedented Detail In Pulsar 6500 Light-Years From Earth” 

    Dunlap Institute bloc
    From Dunlap Institute for Astronomy and Astrophysics

    At U Toronto

    May 23, 2018

    CONTACT INFORMATION:

    Robert Main
    Department of Astronomy & Astrophysics
    Dunlap Institute for Astronomy & Astrophysics (Associate)
    University of Toronto
    e: main@astro.utoronto.ca

    Chris Sasaki
    Communications Coordinator | Press Officer
    Dunlap Institute for Astronomy & Astrophysics
    University of Toronto
    w: dunlap.utoronto.ca
    p: 416-978-6613
    e: csasaki@dunlap.utoronto.ca

    1
    The pulsar PSR B1957+20 is seen in the background through the cloud of gas enveloping its brown dwarf star companion. Image: Dr. Mark A. Garlick; Dunlap Institute for Astronomy & Astrophysics, University of Toronto.

    A team of astronomers has performed one of the highest resolution observations in astronomical history by observing two intense regions of radiation, 20 kilometres apart, around a star 6500 light-years away.

    The observation is equivalent to using a telescope on Earth to see a flea on the surface of Pluto.

    The extraordinary observation was made possible by the rare geometry and characteristics of a pair of stars orbiting each other. One is a cool, lightweight star called a brown dwarf, which features a “wake” or comet-like tail of gas. The other is an exotic, rapidly spinning star called a pulsar.

    “The gas is acting like a magnifying glass right in front of the pulsar,” says Robert Main, lead author of the paper describing the observation being published May 24 in the journal Nature. “We are essentially looking at the pulsar through a naturally occurring magnifier which periodically allows us to see the two regions separately.”

    Main is a PhD astronomy student in the Department of Astronomy & Astrophysics at the University of Toronto, working with colleagues at the University of Toronto’s Dunlap Institute for Astronomy & Astrophysics and Canadian Institute for Theoretical Astrophysics, and the Perimeter Institute.

    The pulsar is a neutron star that rotates rapidly—over 600 times a second. As the pulsar spins, it emits beams of radiation from the two hotspots on its surface. The intense regions of radiation being observed are associated with the beams.

    The brown dwarf star is about a third the diameter of the Sun. It is roughly two million kilometres from the pulsar—or five times the distance between the Earth and the moon—and orbits around it in just over 9 hours. The dwarf companion star is tidally locked to the pulsar so that one side always faces its pulsating companion, the way the moon is tidally locked to the Earth.

    Because it is so close to the pulsar, the brown dwarf star is blasted by the strong radiation coming from its smaller companion. The intense radiation from the pulsar heats one side of the relatively cool dwarf star to the temperature of our Sun, or some 6000°C.

    The blast from the pulsar could ultimately spell its companion’s demise. Pulsars in these types of binary systems are called “black widow” pulsars. Just as a black widow spider eats its mate, it is thought the pulsar, given the right conditions, could gradually erode gas from the dwarf star until the latter is consumed.

    In addition to being an observation of incredibly high resolution, the result could be a clue to the nature of mysterious phenomena known as Fast Radio Bursts, or FRBs.

    “Many observed properties of FRBs could be explained if they are being amplified by plasma lenses,” say Main. “The properties of the amplified pulses we detected in our study show a remarkable similarity to the bursts from the repeating FRB, suggesting that the repeating FRB may be lensed by plasma in its host galaxy.”

    Additional notes:

    1. The pulsar is designated PSR B1957+20. Previous work led by Main’s co-author, Prof. Marten van Kerkwijk, from the University of Toronto, suggests that it is likely one of the most massive pulsars known, and further work to accurately measure its mass will help in understanding how matter behaves at the highest known densities, and equivalently, how massive a neutron star can be before collapsing into a black hole.

    2. Main and his co-authors used data obtained with the Arecibo Observatory radio telescope before Hurricane Maria damaged the telescope in September 2017.


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

    The collaborators will use the telescope to make follow-up observations of PSR B1957+20.

    See the full article here .


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

    Please help promote STEM in your local schools.
    stem
    Stem Education Coalition

    Dunlap Institute campus

    The Dunlap Institute is committed to sharing astronomical discovery with the public. Through lectures, the web, social and new media, an interactive planetarium, and major events like the Toronto Science Festival, we are helping to answer the public’s questions about the Universe.
    Our work is greatly enhanced through collaborations with the Department of Astronomy & Astrophysics, Canadian Institute for Theoretical Astrophysics, David Dunlap Observatory, Ontario Science Centre, Royal Astronomical Society of Canada, the Toronto Public Library, and many other partners.

     
  • richardmitnick 4:02 pm on November 14, 2017 Permalink | Reply
    Tags: , , , , Dunlap Institute for Astronomy and Astrophysics, , ,   

    From Dunlap: “Major Upgrade Increases Power of Radio Telescope to Probe the Universe 

    Dunlap Institute bloc
    Dunlap Institute for Astronomy and Astrophysics

    Nov 14, 2017
    CONTACT INFORMATION:

    Prof. Bryan Gaensler, Director
    Dunlap Institute for Astronomy & Astrophysics
    University of Toronto
    416-978-6223
    bgaensler@dunlap.utoronto.ca
    http://www.dunlap.utoronto.ca/prof-bryan-gaensler

    Chris Sasaki
    Communications Coordinator | Press Officer
    Dunlap Institute for Astronomy & Astrophysics
    University of Toronto
    416-978-6613
    csasaki@dunlap.utoronto.ca

    SKA Murchison Widefield Array

    The Murchison Widefield Array (MWA), a radio telescope in the outback of Western Australia, has completed a planned major upgrade, making it ten times more sensitive and doubling its ability to resolve detail.

    Astronomers are using the MWA to make a detailed map of the entire southern radio sky. They are also using it to make observations of hydrogen gas from an epoch of the Universe when the first stars and galaxies were forming; study the Milky Way Galaxy’s magnetic field; and investigate radio sources like pulsars, X-ray binary stars and neutron stars.

    “The original MWA opened our eyes to a new view of the radio sky,” says Prof. Bryan Gaensler, Director of the Dunlap Institute for Astronomy & Astrophysics, and Canadian representative on the MWA Board of Partners. “This upgrade greatly sharpens that view, and allows us to study in detail the new objects that the MWA discovered earlier.”

    The MWA is one of four precursor telescopes for the Square Kilometre Array (SKA) which, when completed in the mid-2020s, will be the largest radio telescope ever built.

    SKA Square Kilometer Array

    It will have a total collecting area of a square kilometre, with antennas located in Australia and South Africa. SKA will be a ground-breaking instrument which astronomers will use to conduct new tests of General Relativity, observe the very first stars and galaxies, and investigate dark energy and cosmic magnetism.

    The MWA upgrade marks the completion of Phase Two in its development with the addition of 128 new antenna stations to the existing 128. Each station comprises 16 antennas for a total of over four thousand antennas arranged within an area with a diameter of roughly six kilometres.

    The array is located at the Murchison Radio-astronomy Observatory in Western Australia and is operated by an international consortium led by Curtin University and which includes partners from Australia, India, New Zealand, China, the United States and Canada. The University of Toronto officially joined the consortium in June 2016

    “The MWA is not only an amazing scientific facility in its own right,” says Gaensler, “but it is a vital stepping stone and test-bed for our even more ambitious plans for the SKA.”

    Additional notes:
    1) The Phase Two expansion of the MWA was partly funded by a $1 million grant as part of the Australian Research Council (ARC) Linkage Infrastructure, Equipment and Facilities (LIEF) scheme. A further $1.2 million has been provided by partner institutions.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Dunlap Institute campus

    The Dunlap Institute is committed to sharing astronomical discovery with the public. Through lectures, the web, social and new media, an interactive planetarium, and major events like the Toronto Science Festival, we are helping to answer the public’s questions about the Universe.
    Our work is greatly enhanced through collaborations with the Department of Astronomy & Astrophysics, Canadian Institute for Theoretical Astrophysics, David Dunlap Observatory, Ontario Science Centre, Royal Astronomical Society of Canada, the Toronto Public Library, and many other partners.

     
  • richardmitnick 1:52 pm on April 4, 2017 Permalink | Reply
    Tags: , , , , Dunlap Institute for Astronomy and Astrophysics, The Search for the Radio Cosmic Web and Large-Scale Cosmic Magnetism Begins   

    From Dunlap: “The Search for the Radio Cosmic Web and Large-Scale Cosmic Magnetism Begins” 

    Dunlap Institute bloc
    Dunlap Institute for Astronomy and Astrophysics

    4.3.17
    Dr. Tessa Vernstrom
    Dunlap Institute for Astronomy & Astrophysics
    University of Toronto
    p: 416-978-7299
    e: vernstrom@dunlap.utoronto.ca
    w: dunlap.utoronto.ca

    Prof. Bryan Gaensler, Director
    Dunlap Institute for Astronomy & Astrophysics
    University of Toronto
    p: 416-522-0887
    e: bgaensler@dunlap.utoronto.ca
    w: dunlap.utoronto.ca

    Chris Sasaki
    Communications Co-ordinator
    Dunlap Institute for Astronomy & Astrophysics
    University of Toronto
    p: 416-978-6613
    e: csasaki@dunlap.utoronto.ca
    w: dunlap.utoronto.ca

    1
    A three-dimensional, simulated visualization of the Universe showing galaxies organized into the cosmic web. Image: V.Springel, Max-Planck Institut für Astrophysik, Garching bei München

    Using a novel method, a team of astronomers has performed the most comprehensive search yet for a radio signal from the cosmic web, the vast network of filaments connecting clusters of galaxies.

    The search is an important step forward in mapping the large-scale magnetic field of the Universe because any radio signal from the cosmic web would be generated by the interplay between gas in the filaments and the filaments’ magnetic field.

    “Radio emission from the cosmic web has yet to be detected,” says Tessa Vernstrom. “It is expected to be very faint, spread over large areas, and mixed with emission from other sources such as our Galaxy or other galaxies.”

    So, instead of directly searching for the signal with a radio telescope, the team compared—or cross-correlated—infrared maps of the sky showing the positions of galaxies, with a radio survey of the sky conducted with the Murchison Wide-field Array (MWA), a radio telescope comprising 2000 antennas in the Western Australian outback.

    Murchison Widefield Array,SKA Murchison Widefield Array, Boolardy station in outback Western Australia, at the Murchison Radio-astronomy Observatory (MRO)

    The distribution of galaxies across the sky should trace the cosmic web in the same way that mapping the distribution of cars in a city would trace the city’s streets. Cross-correlating that map with the radio sky survey would then enhance the web’s radio emission so that it stands out in relief like a mountain range on a map.

    Using this method, the team did not directly detect the radio cosmic web, but they did establish a maximum possible brightness for the signal—something astronomers refer to as an upper limit.

    “This was the first real search for the radio cosmic web using this approach,” says Prof. Bryan Gaensler. “And now, we’ve verified that the method works and we’re positioned to search properly using the MWA upgrade to be completed later this year.”


    Aerial view of the Murchison Wide-field Array in Western Australia. Image: MWA project, Curtin University

    The results were published March 22nd in the Monthly Notices of the Royal Astronomical Society. Vernstrom, an astronomer with the Dunlap Institute for Astronomy & Astrophysics, University of Toronto, is the paper’s lead author; Gaensler is a co-author and Director of the Dunlap Institute.

    The cosmic web formed when matter in the early Universe coalesced into a network of filaments made up of both “ordinary” matter and dark matter. Ordinary matter—also known as baryonic matter—is the matter we see in stars, nebulae and galaxies. Dark matter is the enigmatic stuff of the cosmos we can’t detect except through its gravitational effect on ordinary matter.

    Clusters of galaxies formed where matter in the web is densest. But theories suggest that only 50% of baryonic matter formed into galaxies, and that the balance exists outside the galaxies in clouds of gas in the filaments.

    “The radio cosmic web is important to measure,” says Vernstrom, “because detecting it would be an indirect way of finding that missing 50% of the matter.

    “Also, the properties of the signal—how bright it is, how bright it is at different points in history, and so on—can tell us about the properties of the filaments’ magnetic field, as well as the history, mechanics and evolution of how the structure of the Universe formed.”

    “The amazing all-sky view of the MWA has made this challenging experiment possible,” adds Gaensler. “For the first time, we’ve been able to search for the faint signatures of the magnetic Universe, writ large across the sky.”

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Dunlap Institute campus

    The Dunlap Institute is committed to sharing astronomical discovery with the public. Through lectures, the web, social and new media, an interactive planetarium, and major events like the Toronto Science Festival, we are helping to answer the public’s questions about the Universe.
    Our work is greatly enhanced through collaborations with the Department of Astronomy & Astrophysics, Canadian Institute for Theoretical Astrophysics, David Dunlap Observatory, Ontario Science Centre, Royal Astronomical Society of Canada, the Toronto Public Library, and many other partners.

     
  • richardmitnick 5:23 pm on March 8, 2017 Permalink | Reply
    Tags: , , , , Dunlap Institute for Astronomy and Astrophysics, New Survey Finds “Peter Pan” Radio Galaxies That May Never Grow Up   

    From Dunlap: “New Survey Finds “Peter Pan” Radio Galaxies That May Never Grow Up” 

    Dunlap Institute bloc
    Dunlap Institute for Astronomy and Astrophysics

    3.8.17
    Dr. Joseph Callingham
    ASTRON Postdoctoral Fellow
    Netherlands Institute for Radio Astronomy (ASTRON)
    Netherlands Organisation for Scientific Research (NWO)
    p: +31 521 595 785
    e: callingham@astron.nl

    Prof. Bryan Gaensler, Director
    Dunlap Institute for Astronomy & Astrophysics
    University of Toronto
    p: 416-522-0887
    e: bgaensler@dunlap.utoronto.ca

    Dr. Wiebke Ebeling
    Education & Outreach
    ARC Centre of Excellence for All-sky Astrophysics (CAASTRO)
    Curtin Institute of Radio Astronomy
    Curtin University
    Bentley WA 6102, Australia
    p: +61 8 9266 9174
    e: wiebke.ebeling@curtin.edu.au

    Chris Sasaki
    Communications Co-ordinator
    Dunlap Institute for Astronomy & Astrophysics
    University of Toronto
    p: 416-978-6613
    e: csasaki@dunlap.utoronto.ca
    w: dunlap.utoronto.ca

    1
    An artist’s impression of a galaxy within which lies a supermassive black hole. The black hole drives enormous outflows of plasma from the galaxy’s core which produce prodigious amounts of radio emission. In this image, the outflows travel toward the upper left and lower right. Image: ESA/Hubble, L. Calçada (ESO)

    A team of astronomers has doubled the number of known young, compact radio galaxies—galaxies powered by newly energized black holes. The improved tally will help astronomers understand the relationship between the size of these radio sources and their age, as well as the nature of the galaxy itself.

    In particular, it will help astronomers understand why there are so many more young radio galaxies than old.

    “We do not understand how radio galaxies evolve,” says Joseph Callingham, a postdoctoral fellow from the Netherlands Institute for Radio Astronomy (ASTRON) and lead author on the paper describing the result.

    “For a long time, we thought all small galaxies evolved into massive galaxies. However, we have now found far too many small galaxies relative to the large ones. This suggests some never make it to the ‘adult phase’.”

    In a survey of ninety thousand radio galaxies, the astronomers identified 1500 compact galaxies among them. The results are described in a paper published 20 February in The Astrophysical Journal.

    “These compact galaxies used to be as rare as hen’s teeth,” says Prof. Bryan Gaensler, a co-author on the paper and Director of the Dunlap Institute for Astronomy & Astrophysics, University of Toronto. “But now we’ve been able to discover a huge number of new cases. This breakthrough will let us begin to study the overall properties of these unusual and important objects.”

    A radio galaxy is a galaxy that shines brightly at radio wavelengths. A super-massive black hole—typically with the mass of millions of Suns—powers this outpouring of energy.

    Gas and dust fall into the black hole, releasing vast amounts of energy. The energy is focused into two jets of particles, travelling in opposite directions at nearly the speed of light. As the jets blast through the galaxy, each generates its own lobe or hot-spot of radiation as it interacts with the gas in the galaxy.

    According to one model, compact radio sources are young because the jets have not had time to reach far beyond the central black hole. The hot-spots are relatively close together and we see them as compact sources. Over time, the jets reach farther out into the galaxy and even beyond its confines; the hot-spots are farther from each other, and we see a more extended, double-lobed source.

    In this simple model, the overabundance of young, compact radio galaxies raises the question: why don’t young, compact radio galaxies mature into old, extended radio galaxies?

    However, another model argues that the relationship between the age and observed size of a radio galaxy is not so straightforward. That’s because a compact source may be compact, not because it’s young, but because gas within the galaxy is dense enough to prevent the jets from extending far from the central black hole; i.e. it remains compact despite it’s age.

    “This study shows that it is possible a dense environment near the heart of the galaxy hinders and stops galaxy growth,” says Callingham, who did much of the research as a PhD student with the Australian Centre for All-shy Astrophysics (CAASTRO).

    The astronomers made the discovery using data gathered with the Murchison Wide-field Array (MWA), an interferometric radio telescope in the Western Australian outback.


    SKA Murchison Widefield Array,SKA Murchison Widefield Array, Boolardy station in outback Western Australia, at the Murchison Radio-astronomy Observatory (MRO)

    The discovery was possible because, unlike conventional radio telescopes that observe tiny patches of the sky at a time, the MWA sweeps large areas of the sky and is capable of observing across a broader range of wavelengths.

    Additional notes:

    1) The Murchison Wide-field array combines the signals from over 2000 separate antennas. With an area of 2000 square metres, it has a collecting area equivalent to a conventional radio telescope dish. The MWA is located at the Murchison Radio Astronomy Observatory, the future Australian site of the Square Kilometre Array, around 700 kilometres north of Perth in Western Australia. Over the past three years, it has been used to survey 90% of the southern sky.

    2) For more on the GaLactic and Extragalactic All-sky MWA (GLEAM) survey of 300,000 galaxies: http://www.icrar.org/gleam/

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Dunlap Institute campus

    The Dunlap Institute is committed to sharing astronomical discovery with the public. Through lectures, the web, social and new media, an interactive planetarium, and major events like the Toronto Science Festival, we are helping to answer the public’s questions about the Universe.
    Our work is greatly enhanced through collaborations with the Department of Astronomy & Astrophysics, Canadian Institute for Theoretical Astrophysics, David Dunlap Observatory, Ontario Science Centre, Royal Astronomical Society of Canada, the Toronto Public Library, and many other partners.

     
  • richardmitnick 5:33 pm on February 14, 2017 Permalink | Reply
    Tags: , , , , Dunlap Institute for Astronomy and Astrophysics, , ,   

    From Dunlap: “Missing Stars in the Solar Neighbourhood Reveal the Sun’s Speed and Distance to the Centre of the Milky Way Galaxy” 

    Dunlap Institute bloc
    Dunlap Institute for Astronomy and Astrophysics

    Feb 13 2017
    Dr. Jason Hunt
    Dunlap Fellow
    Dunlap Institute for Astronomy & Astrophysics
    University of Toronto
    p: 416-978-3147
    e: jason.hunt@dunlap.utoronto.ca

    Chris Sasaki
    Communications Co-ordinator
    Dunlap Institute for Astronomy & Astrophysics
    University of Toronto
    p: 416-978-6613
    e: csasaki@dunlap.utoronto.ca
    w: dunlap.utoronto.ca

    1
    A composite image shows the Gaia spacecraft against a backdrop of the Milky Way Galaxy. Image: ESA/ATG medialab; background image: ESO/S. Brunier

    Using a novel method and data from the Gaia space telescope, astronomers from the University of Toronto have estimated that the speed of the Sun as it orbits the centre of the Milky Way Galaxy is approximately 240 kilometres per second.

    In turn, they have used that result to calculate that the Sun is approximately 7.9 kiloparsecs from the Galaxy’s centre—or almost twenty-six thousand light-years.

    Using data from the Gaia space telescope and the RAdial Velocity Experiment (RAVE) survey, Jason Hunt and his colleagues determined the velocities of over 200,000 stars relative to the Sun. Hunt is a Dunlap Fellow at the Dunlap Institute for Astronomy & Astrophysics, University of Toronto.

    The collaborators found an unsurprising distribution of relative velocities: there were stars moving slower, faster and at the same rate as the Sun.

    But they also found a shortage of stars with a Galactic orbital velocity of approximately 240 kilometres per second slower than the Sun’s. The astronomers concluded that the missing stars had been stars with zero angular momentum; i.e. they had not been circling the Galaxy like the Sun and the other stars in the Milky Way Galaxy;

    “Stars with very close to zero angular momentum would have plunged towards the Galactic centre where they would be strongly affected by the extreme gravitational forces present there,” says Hunt. “This would scatter them into chaotic orbits taking them far above the Galactic plane and away from the Solar neighbourhood.”

    “By measuring the velocity with which nearby stars rotate around our Galaxy with respect to the Sun,” says Hunt, “we can observe a lack of stars with a specific negative relative velocity. And because we know this dip corresponds to 0 km/sec, it tells us, in turn, how fast we are moving.”

    Hunt and his colleagues then combined this finding with the proper motion of the supermassive blackhole known as Sagittarius A* (“A-star”) that lies at the centre of the Galaxy to calculate the 7.9 kiloparsec distance.

    Proper motion is the motion of an object across the sky relative to distant background objects. They calculated the distance in the same way a cartographer triangulates the distance to a terrestrial landmark by observing it from two different positions a known distance apart.

    The result was published in Astrophysical Journal Letters in December 2017.

    The method was first used by Hunt’s co-author, current chair of the Department of Astronomy & Astrophysics at the University of Toronto, Prof. Ray Calberg, and Carlberg’s collaborator, Prof. Kimmo Innanen. But the result Carlberg and Innanen arrived at was based on less than 400 stars.

    Gaia is creating a dynamic, three-dimensional map of the Milky Way Galaxy by measuring the distances, positions and proper motion of stars. Hunt and his colleagues based their work on the initial data release from Gaia which included hundreds of thousands of stars. By the end of its 5 year mission, the space mission will have mapped well over 1 billion stars.

    The velocity and distance results are not significantly more accurate than other measurements. But according to Hunt, “Gaia’s final release in late 2017 should enable us to increase the precision of our measurement of the Sun’s velocity to within approximately one km/sec, which in turn will significantly increase the accuracy of our measurement of our distance from the Galactic centre.”

    Additional notes:

    1) The RAdial Velocity Experiment, or RAVE, is a survey of stars conducted at the Australian Astronomical Observatory (AAO) between 2003 and 2013. It measured the positions, distances, radial velocities and spectra of half-a-million stars—over two hundred thousand of which are included in Gaia data.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Dunlap Institute campus

    The Dunlap Institute is committed to sharing astronomical discovery with the public. Through lectures, the web, social and new media, an interactive planetarium, and major events like the Toronto Science Festival, we are helping to answer the public’s questions about the Universe.
    Our work is greatly enhanced through collaborations with the Department of Astronomy & Astrophysics, Canadian Institute for Theoretical Astrophysics, David Dunlap Observatory, Ontario Science Centre, Royal Astronomical Society of Canada, the Toronto Public Library, and many other partners.

     
  • richardmitnick 10:01 pm on December 15, 2016 Permalink | Reply
    Tags: , , CHARIS, Dunlap Institute for Astronomy and Astrophysics   

    From Dunlap: “New Planet-hunting Instrument Joins the Search for Super-Jupiters” 

    Dunlap Institute bloc
    Dunlap Institute for Astronomy and Astrophysics

    Dec 15, 2016
    Dr. Jeffrey Chilcote
    Dunlap Fellow
    Dunlap Institute for Astronomy & Astrophysics
    University of Toronto
    p: 416-946-5432
    e: chilcote@dunlap.utoronto.ca

    In November 2016, a powerful new instrument designed to search for distant, Jupiter-like worlds, reached its critical “first-light” milestone. After years of development and testing, the Coronagraphic High Angular Resolution Imaging Spectrograph, or CHARIS, was declared operational and ready to gather data on the Subaru Telescope in Hawaii.

    1
    CHARIS

    NAOJ/Subaru Telescope at Mauna Kea Hawaii, USANAOJ Subaru Telescope interior
    NAOJ/Subaru Telescope at Mauna Kea Hawaii, USA

    CHARIS is the latest of a new breed of astronomical instruments designed to find planets beyond our Solar System—known as exoplanets—by imaging them directly. While the Kepler Space Telescope has found over two thousand exoplanets indirectly by measuring minute changes in the brightness of stars, CHARIS and other recently developed instruments like it allow astronomers to actually see distant worlds.

    “CHARIS has exceeded our expectations, which led to overwhelming demand for observing time even before we’d finished evaluating the instrument,” says CHARIS-team member, Jeff Chilcote, a Dunlap Fellow at the Dunlap Institute for Astronomy & Astrophysics, University of Toronto.

    “With CHARIS, we now have a planet-imaging instrument in the northern hemisphere giving access to a whole new set of stars that complements the sky that the Gemini Planet Imager (GPI) can see from Chile.”

    NOAO Gemini Planet Imager on Gemini South
    NOAO Gemini Planet Imager on Gemini South

    2
    A CHARIS image taken during testing shows the previously identified exoplanetary system around the star HD 8799. The planets are indicated by the red circles; the star is hidden in the centre of the image. Image: CHARIS/Princeton Team and NAOJ

    A typical star is a million times brighter than a planet in orbit around it, so an exoplanet imaging instrument must integrate a powerful combination of technologies in order to find its quarry. First, the adaptive optics (AO) systems of the Subaru Telescope and CHARIS combine to greatly reduce the blurring caused by the Earth’s turbulent atmosphere. Then, a component called a coronograph blocks the light of the star, revealing the much fainter point of light that is the exoplanet.

    But CHARIS is more than an imaging instrument. It is also a spectrograph; it splits the light from its target according to wavelength. The resulting spectrum reveals a wealth of information about the exoplanet, including information about its motions, temperature and chemical composition.

    CHARIS was developed by an international team that includes Chilcote, and is led by Principal Investigators N. Jeremy Kasdin from Princeton University, and Masahiko Hayashi from the National Astronomical Observatory of Japan.

    Chilcote was also a member of the team that developed the Gemini Planet Imager instrument. GPI is on the Gemini South Telescope in northern Chile and spied its first exoplanet in August, 2015.

    The CHARIS team will begin their search for distant worlds in February 2017.

    Additional notes:

    The CHARIS project included, in addition to Kasdin, Hayashi and Chilcote, a large team of researchers. The CHARIS instrument was designed and built at Princeton under the direction of Tyler Groff, who now works for NASA’s Goddard Space Flight Center. Other team members included: Michael Galvin, Michael Carr, Craig Loomis, Norman Jarosik, Johnny Greco, Robert Lupton, Edwin Turner, James Gunn and Gillian Knapp of Princeton; Mary Anne Limbach of Limbach Optics; Nemanja Johanovic, of the Subaru Telescope; and Timothy Brandt of the Institute for Advanced Study.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Dunlap Institute campus

    The Dunlap Institute is committed to sharing astronomical discovery with the public. Through lectures, the web, social and new media, an interactive planetarium, and major events like the Toronto Science Festival, we are helping to answer the public’s questions about the Universe.
    Our work is greatly enhanced through collaborations with the Department of Astronomy & Astrophysics, Canadian Institute for Theoretical Astrophysics, David Dunlap Observatory, Ontario Science Centre, Royal Astronomical Society of Canada, the Toronto Public Library, and many other partners.

     
  • richardmitnick 3:00 pm on December 8, 2016 Permalink | Reply
    Tags: André van Staden, , , Dunlap Institute for Astronomy and Astrophysics, John Antoniadis, Millisecond pulsar (MSP) binary system   

    From Dunlap: “Amateur Astronomer Helps Uncover Secrets of Unique Pulsar Binary System” 

    Dunlap Institute bloc
    Dunlap Institute for Astronomy and Astrophysics

    12.8.16
    Contact details:

    Dr. John Antoniadis
    Dunlap Institute for Astronomy & Astrophysics
    University of Toronto
    p: 416-946-5432
    e: antoniadis@dunlap.utoronto.ca
    w: http://www.dunlap.utoronto.ca/dr-john-antoniadis-2
    Twitter: @astro_vegan

    André van Staden
    Bredasdorp, Western Cape
    South Africa
    p: +27-28-424-2796
    e: andre@etiming.co.za

    A professional astrophysicist and an amateur astronomer have teamed up to reveal surprising details about an unusual millisecond pulsar (MSP) binary system comprising one of the fastest-spinning pulsars in our Galaxy and its unique companion star.

    1
    Artist’s rendition of a typical millisecond pulsar binary system in which the shape of the companion star (l.) is deformed by the gravitational pull of the pulsar (r.) seen emitting beams of radiation. Credit: NASA

    Their observations, to be published in the Astrophysical Journal in December, are the first to identify “star spots” on an MSP’s companion star. Plus, the observations show that the companion has a strong magnetic field, and provide clues into why pulsars in some MSP binaries switch on and off.

    John Antoniadis, a Dunlap Fellow with the Dunlap Institute for Astronomy & Astrophysics, University of Toronto, and André van Staden, an amateur astronomer from South Africa, analyzed observations of the brightness of the companion star made by van Staden over a 15-month period, with his 30cm reflector telescope and CCD camera in his backyard observatory in Western Cape. The analysis revealed an unexpected rise and fall in the star’s brightness.

    In a typical MSP binary, the gravity of the pulsar distorts the shape of the companion star, pulling it into a teardrop-shape. As it circles the pulsar, we see a cyclical rise and fall in the companion’s brightness. The companion is brightest at two points in its orbit, when we see its broad, tear-shaped profile; it is dimmest midway between those two points, when we see its smallest, circular profile. Naturally, the light curve measuring the brightness rises and falls in step with the companion’s orbital period.

    2
    André van Staden in his home observatory with his 30cm reflector telescope. Credit: André van Staden

    But Antoniadis and van Staden’s observations revealed that the brightness of the companion wasn’t in sync with its 15-hour orbital period; instead the star’s peaks in brightness occur progressively later relative to the companion’s orbital position.

    Antoniadis and van Staden concluded that this was caused by “starspots”, the equivalent of our Sun’s sunspots, and that the spots were lowering the brightness of the star. What’s more, the spots were much larger relative to the companion star’s diameter than our Sun’s sunspots.

    They also realized that the companion star is not tidally locked to the pulsar—as the moon is to the Earth. Instead, they concluded that the companion’s rotational period is slightly shorter than its orbital period, resulting in the unexpected light curve.

    The presence of starspots also led the collaborators to infer that the star has a strong magnetic field, a prerequisite of such spots.

    A dedicated non-professional astronomer for many years, van Staden has a particular interest in pulsars and in 2014 came across Antoniadis’ research website listing MSP binaries with optical companions.

    “I noted that the binary system MSP J1723-2837 is well suited for observing from South Africa,” van Staden says, “and that a light curve had not yet been determined for this particular system.”

    “I also realized that observations were scarce because professionals do not have the luxury of using professional instruments for continuous observations. On the other hand, non-professionals can make these long-term observations.”

    “The dataset was unlike anything I had ever seen,” says Antoniadis on receiving van Staden’s data, “both in terms of quality and timespan. And I urged André to continue observing for as long as possible.”

    Observations such as van Staden’s are critical in answering questions about the evolution and complex relationship between the MSP and its companion in “black widow” and “redback” binaries—pairs of stars in which the pulsar, like its arachnid namesake, devours its companion.

    In a typical scenario, a newly formed neutron star feeds off of gas gravitationally pulled from the companion. As the pulsar gains mass, it also gains angular momentum and spins faster.

    Eventually, the neutron star is rotating hundreds of times a second. At this point, it enters the next phase of its evolution. The neutron star begins to emit beams of intense radiation that we see as a rapidly pulsating signal: a pulsar is born.

    At this point, the pulsar also begins to give off intense gamma-ray radiation and a strong stellar wind that staunch the flow of material from its neighbour. The companion is no longer being cannibalized by the pulsar, but it has only traded the means by which it is being consumed. Now the radiation and wind from the pulsar are so intense they begin to erode the doomed star.

    As complex as these MSP binary systems are, they have only gotten more perplexing in recent years with observations that pulsars turn off and return to a state in which they are feeding off material from their companion—and that they can make this transition multiple times.

    It has been suggested that the pulsar’s stellar wind and radiation may be behind the transition. But an additional result from Antoniadis and van Staden’s observations is that the stellar wind from the pulsar is not affecting the companion.

    Typically, a pulsar’s strong stellar wind and intense radiation output create a “hotspot” on the pulsar-side of the companion. It is as if the star has a “day” and “night” side. But the presence of the hotspot was not detectable in the data. This could mean that the wind is either absent entirely or is blowing in a direction other than toward the star.

    Either way, this suggests that the companion’s magnetic field—and not the pulsar’s stellar wind and radiation—may be the mechanism that turns off pulsars.

    Supplementary notes:

    1) The MSP lies 2500 light-years away, in the direction of the constellation Sagittarius. It rotates 540 times per second. The distance between the two stars is roughly 2 million kilometres, or 1/30th the distance between the Sun and Mercury. The pulsar is 1.3 times the mass of the Sun; the companion is 0.4 times the mass of the Sun.

    2) Eclipsing MSPs are classified based on the mass of their companion star: “Black widow” companions are a few hundredths the mass of the Sun; the more massive “redback” companions range from 0.2 to 0.7 times the mass of the Sun.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Dunlap Institute campus

    The Dunlap Institute is committed to sharing astronomical discovery with the public. Through lectures, the web, social and new media, an interactive planetarium, and major events like the Toronto Science Festival, we are helping to answer the public’s questions about the Universe.
    Our work is greatly enhanced through collaborations with the Department of Astronomy & Astrophysics, Canadian Institute for Theoretical Astrophysics, David Dunlap Observatory, Ontario Science Centre, Royal Astronomical Society of Canada, the Toronto Public Library, and many other partners.

     
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