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  • richardmitnick 2:54 pm on November 10, 2018 Permalink | Reply
    Tags: "Red Book", , , , , SKA - Square Kilometre Array   

    From SKA: “New paper highlights breadth of cosmology to be done with SKA” 


    From SKA

    8 November 2018

    A new paper published yesterday highlights the potential of the SKA to tackle key questions of cosmology, by presenting a detailed overview of the various observation campaigns that can be conducted with the telescope once built.

    1
    The SKA will probe key issues in cosmology and investigate why the Universe is expanding at an accelerating rate. (Credit: NASA/WMAP)

    Universe map Sloan Digital Sky Survey (SDSS) 2dF Galaxy Redshift Survey

    Cosmology is the study of the origin and fate of the Universe. Cosmologists believe that ordinary matter – the matter that forms everything we see including planets and galaxies – only accounts for around 5% of the total mass & energy content of the Universe. Two mysterious components seem to constitute the rest with dark matter – matter we can’t see directly but whose gravitational effects on normal matter we can observe – constituting around 27% of the remaining content and dark energy – the force causing the Universe to expand at an accelerated rate – accounting for the remaining 68%.

    The Red Book as it is called is the product of the SKA’s Cosmology Science Working Group, a group of around 130 scientists from 70 different institutes in 19 countries interested in using the SKA that represents the wider cosmology community*. It builds on the work of the 2015 SKA Science Book, taking into account the major developments in the field since then. With 46 authors from 36 institutes contributing directly to the writing of the paper, it represents a significant piece of work on the science potential of the SKA to address key issues in cosmology such as dark matter and dark energy.

    “We know the Universe is expanding at an accelerating rate, but we don’t yet understand why,” explains Prof. Richard Battye, co-chair of the working group from the University of Manchester. “One of the SKA’s main science goals is to investigate this, by looking at the distribution of the most basic element, hydrogen, throughout the cosmos. We hope to go beyond what is now considered the ‘standard’ cosmological model and further refine our estimates of the amounts of dark matter and dark energy at any given time in the Universe.”

    The Red Book details the cosmological surveys that the SKA will carry out, and the science they will enable, including establishing the proportion of dark energy in the Universe thanks to percent-level precision measurements of its expansion rate over the last 12 billion years.

    “Science is a constantly evolving field, so we have to update our research to reflect new discoveries and the advance of techniques,” adds SKA Project Scientist Dr. Anna Bonaldi, a co-author of the paper. “As we near the start of construction, the design of the SKA has also matured, so this needs to be reflected in our predictions.”

    There have been major discoveries in the past few years which have implications for the field of cosmology, including the detection of gravitational waves predicted by Einstein by the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO) in the United States, and the detection by the EDGES experiment located on the site of the future SKA-low telescope in Western Australia of what could be the signal from some of the first stars to form in the universe, one of the key science goals of the SKA.

    EDGES telescope in a radio quiet zone at the Murchison Radio-astronomy Observatory in Western Australia.

    These discoveries bring new questions within cosmology, especially on the nature of dark matter. Astronomers are now working on their observational implications and how the SKA could help to confirm the results, in particular through synergies with other upcoming ground-breaking telescopes which observe the Universe at different wavelengths such as ESA’s Euclid space telescope and the Large Synoptic Survey Telescope (LSST) being built in Chile.

    ESA/Euclid spacecraft

    LSST


    LSST Camera, built at SLAC



    LSST telescope, currently under construction on the El Peñón peak at Cerro Pachón Chile, a 2,682-meter-high mountain in Coquimbo Region, in northern Chile, alongside the existing Gemini South and Southern Astrophysical Research Telescopes.

    “The SKA will be the first radio telescope to be a major actor in the field of cosmology,” says Dr. Laura Wolz, co-chair of the working group and a Research Fellow at the University of Melbourne. “With it we’ll be able to produce the first ever map of the large-scale structure of the Universe back to a time when it was 2.2 billion years old – this is incredibly exciting for cosmologists, as it will enable new science and unpredicted discoveries.”

    *A total of 13 Science Working Groups and Focus Groups representing more than 500 scientists across 20 countries work on developing the science case of the SKA. From Cosmology to Magnetism & Solar Physics, they cover the various fields of interested users from the astronomical community.

    See the full article here .

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    SKA ASKAP Pathefinder Telescope

    SKA Meerkat telescope, 90 km outside the small Northern Cape town of Carnarvon, SA


    SKA Meerkat Telescope

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


    SKA Murchison Wide Field Array
    About SKA

    The Square Kilometre Array will be the world’s largest and most sensitive radio telescope. The total collecting area will be approximately one square kilometre giving 50 times the sensitivity, and 10 000 times the survey speed, of the best current-day telescopes. The SKA will be built in Southern Africa and in Australia. Thousands of receptors will extend to distances of 3 000 km from the central regions. The SKA will address fundamental unanswered questions about our Universe including how the first stars and galaxies formed after the Big Bang, how dark energy is accelerating the expansion of the Universe, the role of magnetism in the cosmos, the nature of gravity, and the search for life beyond Earth. Construction of phase one of the SKA is scheduled to start in 2016. The SKA Organisation, with its headquarters at Jodrell Bank Observatory, near Manchester, UK, was established in December 2011 as a not-for-profit company in order to formalise relationships between the international partners and centralise the leadership of the project.

    The Square Kilometre Array (SKA) project is an international effort to build the world’s largest radio telescope, led by SKA Organisation. The SKA will conduct transformational science to improve our understanding of the Universe and the laws of fundamental physics, monitoring the sky in unprecedented detail and mapping it hundreds of times faster than any current facility.

    Already supported by 10 member countries – Australia, Canada, China, India, Italy, New Zealand, South Africa, Sweden, The Netherlands and the United Kingdom – SKA Organisation has brought together some of the world’s finest scientists, engineers and policy makers and more than 100 companies and research institutions across 20 countries in the design and development of the telescope. Construction of the SKA is set to start in 2018, with early science observations in 2020.

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  • richardmitnick 3:58 pm on October 10, 2018 Permalink | Reply
    Tags: ASKAP is located at CSIRO’s Murchison Radio-astronomy Observatory (MRO) in Western Australia, ASKAP telescopes to rule fast radio-burst hunt, , , , , , CSIRO acknowledges the Wajarri Yamaji as the traditional owners of the MRO site, , , SKA - Square Kilometre Array   

    From Commonwealth Scientific and Industrial Research Organisation CSIRO: “CSIRO telescope almost doubles known number of mysterious ‘fast radio bursts'” 

    CSIRO bloc

    From Commonwealth Scientific and Industrial Research Organisation CSIRO

    Australian researchers using a CSIRO radio telescope in Western Australia have nearly doubled the known number of ‘fast radio bursts’— powerful flashes of radio waves from deep space.

    1
    Antennas of CSIRO’s Australian SKA Pathfinder (ASKAP) radio telescope. Credit: CSIRO/Alex Cherney

    2
    An artist’s impression of CSIRO’s Australian SKA Pathfinder (ASKAP) radio telescope observing ‘fast radio bursts’ in ‘fly’s-eye mode’. Each antenna points in a slightly different direction, giving maximum sky coverage. ©OzGrav, Swinburne University of Technology

    3
    (L-R) Lead author Dr Ryan Shannon (Swinburne/OzGrav), with co-authors Dr Keith Bannister (CSIRO) and Dr Jean-Pierre Macquart (Curtin/ICRAR). ©Inspireworks

    4
    Dishes of CSIRO’s Australian Square Kilometre Array Pathfinder in ‘fly’s-eye mode’ ©Kim Steel

    The team’s discoveries include the closest and brightest fast radio bursts ever detected.

    Their findings were reported today in the journal Nature .

    Fast radio bursts come from all over the sky and last for just milliseconds.

    Scientists don’t know what causes them but it must involve incredible energy—equivalent to the amount released by the Sun in 80 years.

    “We’ve found 20 fast radio bursts in a year, almost doubling the number detected worldwide since they were discovered in 2007,” lead author Dr Ryan Shannon, from Swinburne University of Technology and the OzGrav ARC Centre of Excellence said.

    “Using the new technology of the Australia Square Kilometre Array Pathfinder (ASKAP), we’ve also proved that fast radio bursts are coming from the other side of the Universe rather than from our own galactic neighbourhood.”

    Co-author Dr Jean-Pierre Macquart, from the Curtin University node of the International Centre for Radio Astronomy Research (ICRAR), said bursts travel for billions of years and occasionally pass through clouds of gas.

    “Each time this happens, the different wavelengths that make up a burst are slowed by different amounts,” he said.

    “Eventually, the burst reaches Earth with its spread of wavelengths arriving at the telescope at slightly different times, like swimmers at a finish line.

    “Timing the arrival of the different wavelengths tells us how much material the burst has travelled through on its journey.

    “And because we’ve shown that fast radio bursts come from far away, we can use them to detect all the missing matter located in the space between galaxies—which is a really exciting discovery.”

    CSIRO’s Dr Keith Bannister, who engineered the systems that detected the bursts, said ASKAP’s phenomenal discovery rate is down to two things.

    “The telescope has a whopping field of view of 30 square degrees, 100 times larger than the full Moon,” he said.

    “And, by using the telescope’s dish antennas in a radical way, with each pointing at a different part of the sky, we observed 240 square degrees all at once—about a thousand times the area of the full Moon.

    “ASKAP is astoundingly good for this work.”

    Dr Shannon said we now know that fast radio bursts originate from about halfway across the Universe but we still don’t know what causes them or which galaxies they come from.

    The team’s next challenge is to pinpoint the locations of bursts on the sky.

    “We’ll be able to localise the bursts to better than a thousandth of a degree,” Dr Shannon said.

    “That’s about the width of a human hair seen 10 metres away, and good enough to tie each burst to a particular galaxy.”

    ASKAP is located at CSIRO’s Murchison Radio-astronomy Observatory (MRO) in Western Australia, and is a precursor for the future Square Kilometre Array (SKA) telescope.

    The SKA could observe large numbers of fast radio bursts, giving astronomers a way to study the early Universe in detail.

    CSIRO acknowledges the Wajarri Yamaji as the traditional owners of the MRO site.

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    CSIRO campus

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

     
  • richardmitnick 10:50 am on October 3, 2018 Permalink | Reply
    Tags: , , , , , , , SKA - Square Kilometre Array, Still a ways to go   

    From École Polytechnique Fédérale de Lausanne: “New tool helps scientists better target the search for alien life” 

    EPFL bloc

    From École Polytechnique Fédérale de Lausanne

    1
    © iStock

    02.10.18
    Sarah Perrin

    An EPFL scientist has developed a novel approach that boosts the chances of finding extraterrestrial intelligence in our galaxy. His method uses probability theory to calculate the possibility of detecting an extraterrestrial signal (if there is one) at a given distance from Earth.

    Could there be another planet out there with a society at the same stage of technological advancement as ours? To help find out, EPFL scientist Claudio Grimaldi, working in association with the University of California, Berkeley, has developed a statistical model that gives researchers a new tool in the search for the kind of signals that an extraterrestrial society might emit. His method – described in an article appearing today in PNAS – could also make the search cheaper and more efficient.

    Astrophysics initially wasn’t Grimaldi’s thing; he was interested more in the physics of condensed matter. Working at EPFL’s Laboratory of Physics of Complex Matter, his research involved calculating the probabilities of carbon nanotubes exchanging electrons. But then he wondered: if the nanotubes were stars and the electrons were signals generated by extraterrestrial societies, could we calculate the probability of detecting those signals more accurately?

    This is not pie-in-the-sky research – scientists have been studying this possibility for nearly 60 years. Several research projects concerning the search for extraterrestrial intelligence (SETI) have been launched since the late 1950s, mainly in the United States.




    SETI@home, a BOINC project originated in the Space Science Lab at UC Berkeley


    SETI/Allen Telescope Array situated at the Hat Creek Radio Observatory, 290 miles (470 km) northeast of San Francisco, California, USA, Altitude 986 m (3,235 ft)


    Laser SETI, the future of SETI Institute research

    The idea is that an advanced civilization on another planet could be generating electromagnetic signals, and scientists on Earth might be able to pick up those signals using the latest high-performance radio telescopes.

    Renewed interest

    Despite considerable advances in radio astronomy and the increase in computing power since then, none of those projects has led to anything concrete. Some signals have been recorded, like the Wow! signal in 1977, but scientists could not pinpoint their origin.

    Wow! signal

    And none of them has been repeated or seems credible enough to be attributable to alien life.

    But that doesn’t mean scientists have given up. On the contrary, SETI has seen renewed interest following the discovery of the many exoplanets orbiting the billions of suns in our
    galaxy. Researchers have designed sophisticated new instruments – like the Square Kilometre Array, a giant radio telescope being built in South Africa and Australia with a total collecting area of one square kilometer – that could pave the way to promising breakthroughs.

    And Russian entrepreneur Yuri Milner recently announced an ambitious program called Breakthrough Listen, which aims to cover 10 times more sky than previous searches and scan a much wider band of frequencies. Milner intends to fund his initiative with 100 million dollars over 10 years.

    1

    Lick Automated Planet Finder telescope, Mount Hamilton, CA, USA



    GBO radio telescope, Green Bank, West Virginia, USA


    CSIRO/Parkes Observatory, located 20 kilometres north of the town of Parkes, New South Wales, Australia


    SKA Meerkat telescope, 90 km outside the small Northern Cape town of Carnarvon, SA

    “In reality, expanding the search to these magnitudes only increases our chances of finding something by very little. And if we still don’t detect any signals, we can’t necessarily conclude with much more certainty that there is no life out there,” says Grimaldi.

    Still a ways to go

    4
    Schematic view of the Milky Way showing six isotropic extraterrestrial emission processes forming spherical shells filled by radio signals. The outer radii of the spherical shells are proportional to the time at which the signals were first emitted, while the thicknesses are proportional to the duration of the emissions. In this example, the Earth is illuminated by one of these signals. ©Claudio Grimaldi.

    The advantage of Grimaldi’s statistical model is that it lets scientists interpret both the success and failure to detect signals at varying distances from the Earth. His model employs Bayes’ theorem to calculate the remaining probability of detecting a signal within a given radius around our planet. For example, even if no signal is detected within a radius of 1,000 light years, there is still an over 10% chance that the Earth is within range of hundreds of similar signals from elsewhere in the galaxy, but that our radio telescopes are currently not powerful enough to detect them. However, that probability rises to nearly 100% if even just one signal is detected within the 1,000-light-year radius. In that case, we could be almost certain that our galaxy is full of alien life.

    After factoring in other parameters like the size of the galaxy and how closely packed its stars are, Grimaldi estimates that the probability of detecting a signal becomes very slight only at a radius of 40,000 light years. In other words, if no signals are detected at this distance from the Earth, we could reasonably conclude that no other civilization at the same level of technological development as ours is detectable in the galaxy. But so far, scientists have been able to search for signals within a radius of “just” 40 light years.

    So there’s still a ways to go. Especially since these search methods can’t detect alien civilizations that may be in primordial stages or that are highly advanced but haven’t followed the same technological trajectory as ours.

    See the full article here .

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    Please help promote STEM in your local schools.

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    EPFL campus

    EPFL is Europe’s most cosmopolitan technical university. It receives students, professors and staff from over 120 nationalities. With both a Swiss and international calling, it is therefore guided by a constant wish to open up; its missions of teaching, research and partnership impact various circles: universities and engineering schools, developing and emerging countries, secondary schools and gymnasiums, industry and economy, political circles and the general public.

     
  • richardmitnick 11:35 am on August 6, 2018 Permalink | Reply
    Tags: , , , , , SKA - Square Kilometre Array, SKA Telescope Manager consortium   

    From SKA: “Indian-led Telescope Manager consortium concludes design work on SKA” 


    From SKA

    1
    Members of the Telescope Manager consortium gathered at SKA Global Headquarters in the UK for the Critical Design Review in April. Credit: SKAO

    6 August 2018

    After four and a half years, the international Telescope Manager (TM) consortium has formally concluded its work on the architectural design of a fundamental part of the software for the Square Kilometre Array: the nervous system of the Observatory, which is called the Telescope Manager.

    Formed in November 2013, the consortium was tasked with designing the crucial software that will control, monitor and operate the SKA telescopes. TM brought expertise in the field of Monitoring and Control for large-scale, complex systems and design of user interface experience.

    Led by India’s National Centre for Radio Astrophysics (NCRA), the international consortium comprised nine institutions in seven countries.*

    TM Consortium Lead Professor Yashwant Gupta from NCRA said “We can all take pride in the fact that we’ve successfully designed the software that will operate the world’s largest radio telescope. I would like to sincerely thank all the members of our international team for their hard work over the past few years that made it possible to achieve this important milestone.”

    The TM work was part of a global effort by 12 international engineering consortia representing 500 engineers and scientists in 20 countries. Nine of the consortia focus on a component of the telescope, each critical to the overall success of the project, while three others focus on developing advanced instrumentation for the telescope.

    After four years of intense design work, the nine consortia are having their Critical Design Reviews or CDRs. In this final stage, the proposed design must meet the project’s tough engineering requirements to be approved, so that a construction proposal for the telescope can be developed.

    Following their successful CDR in April 2018, the TM consortium set about making the final adjustments to their proposed design which they have now completed. While the consortium now formally ceases to exist, the SKA Organisation continues to work with NCRA and the other former consortium members on the System Critical Design Review development and the SKA construction proposal, where their expertise will be required to make sure the TM design works alongside the other elements.

    “The work done by the consortium has been outstanding,” said Maurizio Miccolis, TM Project Manager for the SKA Organisation. “We can now take it forward into the next phase of the SKA, which brings us one step closer to construction.”

    *Consortium members included the Commonwealth Scientific and Industrial Research Council (CSIRO) in Australia, the National Research Council of Canada (NRC), TCS Research and Innovation and Persistent Systems in India, Italy’s National Institute for Astrophysics (INAF), Portugal’s ENGAGE SKA Consortium through Instituto de Telecomunicações (IT) & the School of Sciences of Porto University, the South African Radio Astronomy Observatory (SARAO), and the UK’s Astronomy Technology Centre funded by the Science and Technology Facilities Council (STFC).

    Find out more about TM’s work, including photos and videos.

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition


    SKA ASKAP Pathefinder Telescope

    SKA Meerkat telescope, 90 km outside the small Northern Cape town of Carnarvon, SA


    SKA Meerkat Telescope

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


    SKA Murchison Wide Field Array

    About NCRA

    The National Centre for Radio Astrophysics (NCRA) of the Tata Institute of Fundamental Research (TIFR), Pune, is one of the premier astronomy research centres in India. It is also the nodal agency for the Indian participation in the SKA. NCRA is responsible for the construction and operation of the Giant Metrewave Radio Telescope (GMRT) which is the largest radio telescope in the world at metrewavelengths. Recently the GMRT has gone through a major upgrade which included many technical improvements, thus enabling astronomers to study numerous cutting-edge scientific research problems. GMRT is already serving as a test-bed for carrying out observations with the SKA and hence has been accorded the status of a “SKA Pathfinder”.

    Read more about NCRA’s contribution to the TM Critical Design Reviews

    About SKA

    The Square Kilometre Array will be the world’s largest and most sensitive radio telescope. The total collecting area will be approximately one square kilometre giving 50 times the sensitivity, and 10 000 times the survey speed, of the best current-day telescopes. The SKA will be built in Southern Africa and in Australia. Thousands of receptors will extend to distances of 3 000 km from the central regions. The SKA will address fundamental unanswered questions about our Universe including how the first stars and galaxies formed after the Big Bang, how dark energy is accelerating the expansion of the Universe, the role of magnetism in the cosmos, the nature of gravity, and the search for life beyond Earth. Construction of phase one of the SKA is scheduled to start in 2016. The SKA Organisation, with its headquarters at Jodrell Bank Observatory, near Manchester, UK, was established in December 2011 as a not-for-profit company in order to formalise relationships between the international partners and centralise the leadership of the project.

    The Square Kilometre Array (SKA) project is an international effort to build the world’s largest radio telescope, led by SKA Organisation. The SKA will conduct transformational science to improve our understanding of the Universe and the laws of fundamental physics, monitoring the sky in unprecedented detail and mapping it hundreds of times faster than any current facility.

    Already supported by 10 member countries – Australia, Canada, China, India, Italy, New Zealand, South Africa, Sweden, The Netherlands and the United Kingdom – SKA Organisation has brought together some of the world’s finest scientists, engineers and policy makers and more than 100 companies and research institutions across 20 countries in the design and development of the telescope. Construction of the SKA is set to start in 2018, with early science observations in 2020.

     
  • richardmitnick 9:15 am on July 4, 2018 Permalink | Reply
    Tags: , , , , Japan’s VERA telescope granted SKA pathfinder status, , SKA - Square Kilometre Array, The VLBI Exploration of Radio Astrometry (VERA) telescope   

    From SKA: “Japan’s VERA telescope granted SKA pathfinder status” 


    From SKA

    3 July 2018

    The VLBI Exploration of Radio Astrometry (VERA) telescope, operated by the National Astronomical Observatory of Japan, has been officially designated as an SKA pathfinder.

    1
    Mizusawa station is one of four across Japan that make up the VERA telescope. (Credit: NAOJ)

    In operation since 2003, VERA uses Very Long Baseline Interferometry (VLBI) to explore the three-dimensional structure of the Milky Way based on high-precision astrometry of Galactic maser sources. It comprises four Cassegrain antennas each measuring 20 metres in diameter.

    VERA joins more than a dozen pathfinder facilities around the globe which are contributing to SKA-related technology and science. Pathfinder telescopes provide valuable information to teams working on the design of the SKA, but unlike precursors they are not located at SKA sites.

    “VERA mainly performs K (22 GHz) and Q (43 GHz) band VLBI observations. Therefore, science cases at such high frequencies will be intensively developed with VERA,” said Prof. Mareki Honma, Director of the Mizusawa VLBI Observatory, which operates the telescope as part of NAOJ. “In future, VERA could enhance SKA VLBI capabilities, providing SKA-mid instrument with the intercontinental, longest baseline. Such a potential will also improve the value of the SKA.”

    SKA-mid, an array of almost 200 dishes in its first phase, will be hosted in South Africa’s Karoo region, incorporating the existing 64-dish MeerKAT precursor telescope.

    SKA Meerkat telescope, 90 km outside the small Northern Cape town of Carnarvon, SA

    It will be engaged in exploring many exciting areas of science, including gravitational waves, pulsars, and the search for signs of life in the galaxy. A later expansion would see SKA baselines extended across the African continent.

    While two of the four VERA antennas are on the Japanese mainland, the other two are located on the outlying Ishigaki and Ogasawara islands. NAOJ notes that the difficulty of accessing these sites can provide important lessons about Telescope Management for the SKA, where teams will face similar issues at remote sites in Australia and South Africa.

    “NAOJ and the Mizusawa VLBI Observatory have skills in all aspects of VLBI science and its techniques. In particular they bring expertise in high-frequency (for SKA) receiver systems, ADCs and VLBI backends that is of great interest to the SKA,” said Prof. Phil Diamond, SKAO Director-General. Analogue to digital convertors (ADCs) convert signals so that they can be transmitted over optical fibre, an important component for the SKA.

    Prof. Diamond added: “We look forward to further collaborations with our Japanese colleagues through VERA and we are hopeful that this will contribute to advancing the SKA case in Japan.”

    Read more about VERA on the project’s website, and learn about other SKA pathfinders and precursors around the world here.

    See the full article here .


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    Please help promote STEM in your local schools.

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    SKA ASKAP Pathefinder Telescope

    SKA Meerkat telescope, 90 km outside the small Northern Cape town of Carnarvon, SA

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


    SKA Murchison Wide Field Array
    About SKA

    The Square Kilometre Array will be the world’s largest and most sensitive radio telescope. The total collecting area will be approximately one square kilometre giving 50 times the sensitivity, and 10 000 times the survey speed, of the best current-day telescopes. The SKA will be built in Southern Africa and in Australia. Thousands of receptors will extend to distances of 3 000 km from the central regions. The SKA will address fundamental unanswered questions about our Universe including how the first stars and galaxies formed after the Big Bang, how dark energy is accelerating the expansion of the Universe, the role of magnetism in the cosmos, the nature of gravity, and the search for life beyond Earth. Construction of phase one of the SKA is scheduled to start in 2016. The SKA Organisation, with its headquarters at Jodrell Bank Observatory, near Manchester, UK, was established in December 2011 as a not-for-profit company in order to formalise relationships between the international partners and centralise the leadership of the project.

    The Square Kilometre Array (SKA) project is an international effort to build the world’s largest radio telescope, led by SKA Organisation. The SKA will conduct transformational science to improve our understanding of the Universe and the laws of fundamental physics, monitoring the sky in unprecedented detail and mapping it hundreds of times faster than any current facility.

    Already supported by 10 member countries – Australia, Canada, China, India, Italy, New Zealand, South Africa, Sweden, The Netherlands and the United Kingdom – SKA Organisation has brought together some of the world’s finest scientists, engineers and policy makers and more than 100 companies and research institutions across 20 countries in the design and development of the telescope. Construction of the SKA is set to start in 2018, with early science observations in 2020.

     
  • richardmitnick 1:00 pm on December 18, 2017 Permalink | Reply
    Tags: AAVS1-Aperture Array Verification System, , , , , Designing the SKA Telescopes – From lab to Outback: the story of AAVS1 so far, MRO-Murchison Radio-astronomy Observatory, , SKA - Square Kilometre Array, SKA1-low   

    From SKA: “Designing the SKA Telescopes – From lab to Outback: the story of AAVS1 so far” 


    SKA

    18 December 2017

    1
    Designing the SKA telescopes – From lab to Outback: the story of AAVS1 so far. Credit: ICRAR

    It is an understatement to say that designing and building a world-class scientific instrument comes with its challenges. The Aperture Array Verification System (AAVS1) is one of the major milestones in the journey towards delivering the final design for SKA1-low, the Australian arm of the first phase of the SKA telescope, that will eventually consist of 130,000 antennas observing low frequency signals emanating from the cosmos. The team delivering this project recently reported on the successful roll-out of a station made up of 256 antenna prototypes at the Murchison Radio-astronomy Observatory (MRO), located in Western Australia.

    “The journey leading up to the deployment and installation of a full antenna station has been a fantastic experience and a steep learning curve for everyone involved”, said the Netherlands Institute for Radio Astronomy (ASTRON) engineer Pieter Benthem, AAVS1 Project Manager. “It’s one thing to design, simulate and test the antennas and systems for AAVS1 inside a computer and a totally different thing to deal with the practicalities and logistical complexities of deploying the array on a remote site, on the other side of the planet.”

    Overcoming several technical and logistics issues, the AAVS1 team completed the main station of AAVS1 during their most recent site trip in early November. Previous site trips in August and March showed the dedication of the team.

    “Despite being separated from home and family, the team powered on and got a tremendous amount of work done”, added Jader Monari, engineer from the Italian National Institute for Astrophysics (INAF) and AAVS1 Italian group leader. “This fruitful international collaboration showcases much more than just getting ready for the Critical Design Review (CDR) in a few months time. Working at the MRO was quite an experience for many of us coming from the other side of the globe, and the harsh conditions we had to cope with made us bond quite rapidly, with a very positive impact on the team’s performance. Every day, back at Wooleen or Boolardy Station [where the team lodged], we were holding what we called “family meetings”, where we would share joys or frustrations of the day, and discuss the next day’s activities in a professional yet very friendly atmosphere.”

    The AAVS1 project is a key deliverable for the Low Frequency Aperture Array (LFAA) consortium, bringing together a team of experts from Australia, the United Kingdom, Malta, the Netherlands and Italy. LFAA, led by ASTRON, is one of 12 consortia in charge of designing the various elements for the SKA telescope.

    ”Getting the actual designers to the MRO has been a great opportunity to allow them to assemble, test and deploy their design”, added Pieter Benthem. “Several lessons were learned across the board from deployment to commissioning, including details on local materials to be used and feedback towards the next design iteration; all valuable input that will inform the design process ahead of the CDR and help prepare for SKA1-low.”

    “This is really one of those projects where the whole is far greater than the sum of its parts”, commented Philip Gibbs, LFAA Project Manager at the SKA Organisation. “Every single individual has brought a great deal of expertise to the deployment of the full station. To name but a few examples of this truly international team, the design of the AAVS1 antenna prototypes was led by the University of Cambridge in the UK; procurement of fibre optics and circuit board design was done by INAF in Italy; both INAF and ASTRON purchased and produced the digitisers boards, gathering important know-how on different production techniques on a single printed circuit board design; our Maltese colleagues along with a team at Oxford University applied their expertise in the firmware, monitor and control software of the antennas; and of course our Australian colleagues from ICRAR and Curtin University provided all logistical support to bring this prototype to life in the West Australian desert drawing on their extensive expertise for constructing and deploying radio telescopes in remote regions. ICRAR and Curtin engineers also designed the intra-station power and fibre distribution system, without which the AAVS1 antennas would have no power and the signals received would not be able to leave the station. All of this being overseen and managed by ASTRON in the Netherlands—so indeed, a truly global enterprise.”

    The AAVS1 test platform is located at the Murchison Radio-astronomy Observatory (MRO), 800 km north-east of Perth, Western Australia, is home not only to the future SKA1-low telescope but also to the precursor facilities, the Australian SKA Pathfinder (ASKAP) telescope—a 36-dish instrument— and the Murchison Widefield Array (MWA) —comprising 2,048 dipole antennas. The MRO is owned and operated by CSIRO, Australia’s national science agency, which also designed and operates ASKAP. CSIRO’s engineers, responsible for ASKAP operations, have also supported the LFAA team through deployment according to ICRAR’s David Emrich. “CSIRO people are always willing to lend support, tools and in-kind assistance and the engineers, along with the site support staff, have established a really collaborative culture. It makes a difference in this harsh and extremely remote location,” he said.

    3
    Credits: left photo: CSIRO; right photo: ICRAR

    Both of these telescopes have been instrumental in testing and further developing the technologies for the SKA however, the low-frequency MWA telescope provided test and development precedents for AAVS1. Online since mid-2013, MWA receives signals from the early Universe within the bandwidth of 80 to 300 MHz. Through its years of operations and refining of techniques, the MWA has pioneered methods for AAVS1, such as adjusting for the distorting effects of the ionosphere above the Murchison, and also refining the method to reduce the noise inherent in the system. ICRAR also planned the deployment of the LFAA which at the start of pre-construction in 2013 was considered the critical risk to realising SKA1-low. AAVS1 has been informed by the development of the LFAA deployment plan.

    4
    Credit: ICRAR

    However, deploying the AAVS1 prototype has been one of several challenges faced by the LFAA consortium team. Drawing from a decade of engineering work worldwide in low-frequency radio astronomy, the team has learnt from MWA, LOFAR and others operating in the same radio frequency regime and has developed improved antenna designs for SKA1-low. These designs, known as the SKALA prototype design, are a log periodic design with various different rung lengths which enable sensitivity to a wide range of frequencies —which operate from 50 to 650 MHz. The continuous evolution of the SKALA prototype has led to the proposed SKALA4 design, an evolution of SKALA2 which has been deployed on site as part of the AAVS1 project.

    An international panel of experts tasked with evaluating multiple performance and design metrics of various proposed antenna designs, considers the SKALA4 antenna to be the best option for the LFAA Critical Design Review (CDR) in July 2018. A comprehensive report on this design will be presented for the Review in July.

    5
    Credit: ICRAR

    About the LFAA Consortium

    The “Low-Frequency Aperture Array” (LFAA) element is the set of antennas, on-board amplifiers and local processing required for the Aperture Array telescope of the SKA.

    The LFAA consortium is led by the Netherlands Institute for Radio Astronomy (ASTRON) and includes the International Centre for Radio Astronomy Research (ICRAR), Australia; the Key Lab of Aperture Array and Space Application (KLAASA), China; the National Institute for Astrophysics (INAF), Italy; the University of Malta; the Joint Institute for VLBI in Europe (JIVE), the Netherlands; the University of Cambridge, UK; the University of Manchester, UK; the University of Oxford, UK; the Science and Technology Facilities Council (STFC), UK; Observatoire de la Cote d’Azur, France; and Station de Radioastronomie de Nançay, France.

    See the full article here .

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    SKA ASKAP Pathefinder Telescope

    SKA Meerkat telescope, 90 km outside the small Northern Cape town of Carnarvon, SA


    SKA Meerkat Telescope

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


    SKA Murchison Wide Field Array
    About SKA

    The Square Kilometre Array will be the world’s largest and most sensitive radio telescope. The total collecting area will be approximately one square kilometre giving 50 times the sensitivity, and 10 000 times the survey speed, of the best current-day telescopes. The SKA will be built in Southern Africa and in Australia. Thousands of receptors will extend to distances of 3 000 km from the central regions. The SKA will address fundamental unanswered questions about our Universe including how the first stars and galaxies formed after the Big Bang, how dark energy is accelerating the expansion of the Universe, the role of magnetism in the cosmos, the nature of gravity, and the search for life beyond Earth. Construction of phase one of the SKA is scheduled to start in 2016. The SKA Organisation, with its headquarters at Jodrell Bank Observatory, near Manchester, UK, was established in December 2011 as a not-for-profit company in order to formalise relationships between the international partners and centralise the leadership of the project.

    The Square Kilometre Array (SKA) project is an international effort to build the world’s largest radio telescope, led by SKA Organisation. The SKA will conduct transformational science to improve our understanding of the Universe and the laws of fundamental physics, monitoring the sky in unprecedented detail and mapping it hundreds of times faster than any current facility.

    Already supported by 10 member countries – Australia, Canada, China, India, Italy, New Zealand, South Africa, Sweden, The Netherlands and the United Kingdom – SKA Organisation has brought together some of the world’s finest scientists, engineers and policy makers and more than 100 companies and research institutions across 20 countries in the design and development of the telescope. Construction of the SKA is set to start in 2018, with early science observations in 2020.

     
  • richardmitnick 4:02 pm on November 14, 2017 Permalink | Reply
    Tags: , , , , , , , SKA - Square Kilometre Array   

    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 .

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    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 1:49 pm on August 1, 2017 Permalink | Reply
    Tags: , , , , , SKA - Square Kilometre Array, ,   

    From Symmetry: “Tuning in for science” 

    Symmetry Mag

    Symmetry

    08/01/17
    By Mike Perricone

    1
    Square Kilometer Array

    The sprawling Square Kilometer Array radio telescope hunts signals from one of the quietest places on earth.

    SKA South Africa

    When you think of radios, you probably think of noise. But the primary requirement for building the world’s largest radio telescope is keeping things almost perfectly quiet.

    Radio signals are constantly streaming to Earth from a variety of sources in outer space. Radio telescopes are powerful instruments that can peer into the cosmos—through clouds and dust—to identify those signals, picking them up like a signal from a radio station. To do it, they need to be relatively free from interference emitted by cell phones, TVs, radios and their kin.

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

    That’s one reason the Square Kilometer Array is under construction in the Great Karoo, 400,000 square kilometers of arid, sparsely populated South African plain, along with a component in the Outback of Western Australia. The Great Karoo is also a prime location because of its high altitude—radio waves can be absorbed by atmospheric moisture at lower altitudes. SKA currently covers some 1320 square kilometers of the landscape.

    Even in the Great Karoo, scientists need careful filtering of environmental noise. Effects from different levels of radio frequency interference (RFI) can range from “blinding” to actually damaging the instruments. Through South Africa’s Astronomy Geographic Advantage Act, SKA is working toward “radio protection,” which would dedicate segments of the bandwidth for radio astronomy while accommodating other private and commercial RF service requirements in the region.

    “Interference affects observational data and makes it hard and expensive to remove or filter out the introduced noise,” says Bernard Duah Asabere, Chief Scientist of the Ghana team of the African Very Long Baseline Interferometry Network (African VLBI Network, or AVN), one of the SKA collaboration groups in eight other African nations participating in the project.

    2
    The Ghanaian and South African governments on Thursday announced the combination of ‘first light’ science observations, which confirm the successful conversion of the Ghana communications antenna from a redundant telecoms instrument into a functioning Very Long Baseline Interferometry (VLBI) radio telescope.

    Ghana is the first partner country of the African Very Large Baseline Interferometer (VLBI) Network (AVN) to complete the conversion of a communications antenna into a functioning radio telescope.

    SKA “will tackle some of the fundamental questions of our time, ranging from the birth of the universe to the origins of life,” says SKA Director-General Philip Diamond. Among the targets: dark energy, Einstein’s theory of gravity and gravitational waves, and the prevalence of the molecular building blocks of life across the cosmos.

    SKA-South Africa can detect radio spectrum frequencies from 350 megahertz to 14 gigahertz. Its partner Australian component will observe the lower-frequency scale, from 50 to 350 megahertz. Visible light, for comparison, has frequencies ranging from 400 to 800 million megahertz. SKA scientists will process radiofrequency waves to form a picture of their source.

    A precursor instrument to SKA called MeerKat (named for the squirrel-sized critters indigenous to the area), is under construction in the Karoo.

    SKA Meerkat telescope, 90 km outside the small Northern Cape town of Carnarvon, SA

    This array of 16 dishes in South Africa achieved first light on June 19, 2016. MeerKAT focused on 0.01 percent of the sky for 7.5 hours and saw 1300 galaxies—nearly double the number previously known in that segment of the cosmos.

    Since then, MeerKAT met another milestone with 32 integrated antennas. MeerKat will also reach its full array of 64 dishes early next year, making it one of the world’s premier radio telescopes. MeerKAT will eventually be integrated into SKA Phase 1, where an additional 133 dishes will be built. That will bring the total number of antennas for SKA Phase I in South Africa to 197 by 2023. So far, 32 dishes are fully integrated and are being commissioned for science operations.

    On completion of SKA 2 by 2030, the detection area of the receiver dishes will exceed 1 square kilometer, or about 11,000 square feet. Its huge size will make it 50 times more sensitive than any other radio telescope. It is expected to operate for 50 years.

    SKA is managed by a 10-nation consortium, including the UK, China, India and Australia as well as South Africa, and receives support from another 10 countries, including the US. The project is headquartered at Jodrell Bank Observatory in the UK.

    The full SKA will use radio dishes across Africa and Australia, and collaboration members say it will have a farther reach and more detailed images than any existing radio telescope.

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

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

    In preparation for the SKA, South Africa and its partner countries developed AVN to establish a network of radiotelescopes across the African continent. One of its projects is the refurbishing of redundant 30-meter-class antennas, or building new ones across the partner countries, to operate as networked radio telescopes.

    4
    Hartebeesthoek Radio Astronomy Observatory in Gauteng.

    The first project of its kind is the AVN Ghana project, where an idle 32-meter diameter dish has been refurbished and revamped with a dual receiver system at 5 and 6.7 gigahertz central frequencies for use as a radio telescope. The dish was previously owned and operated by the government and the company Vodafone Ghana as a telecommunications facility. Now it will explore celestial objects such as extragalactic nebulae, pulsars and other RF sources in space, such as molecular clouds, called masers.

    Asabere’s group will be able to tap into areas of SKA’s enormous database (several supercomputers’ worth) over the Internet. So will groups in Botswana, Kenya, Madagascar, Mauritius, Mozambique, Namibia and Zambia. SKA is also offering extensive outreach in participating countries and has already awarded 931 scholarships, fellowships and grants.

    Other efforts in Ghana include introducing astronomy in the school curricula, training students in astronomy and related technologies, doing outreach in schools and universities, receiving visiting students at the telescope site and hosting programs such as the West African International Summer School for Young Astronomers taking place this week.

    Asabere, who achieved his advanced degrees in Sweden (Chalmers University of Technology) and South Africa (University of Johannesburg), would like to see more students trained in Ghana, and would like get more researchers on board. He also hopes for the construction of the needed infrastructure, more local and foreign partnerships and strong governmental backing.

    “I would like the opportunity to practice my profession on my own soil,” he says.

    That day might not be far beyond the horizon. The Leverhulme-Royal Society Trust and Newton Fund in the UK are co-funding extensive human capital development programs in the SKA-AVN partner countries. A seven-member Ghanaian team, for example, has undergone training in South Africa and has been instructed in all aspects of the project, including the operation of the telescope.

    Several PhD students and one MSc student from Ghana have received SKA-SA grants to pursue further education in astronomy and engineering. The Royal Society has awarded funding in collaboration with Leeds University to train two PhDs and 60 young aspiring scientists in the field of astrophysics.

    Based on the success of the Leverhulme-Royal Society program, a joint UK-South Africa Newton Fund intervention (DARA—the Development in Africa with Radio Astronomy) has since been initiated in other partner countries to grow high technology skills that could lead to broader economic development in Africa.

    As SKA seeks answers to complex questions over the next five decades, there should be plenty of opportunities for science throughout the Southern Hemisphere. Though it lives in one of the quietest places, SKA hopes to be heard loud and clear.

    See the full article here .

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    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 12:51 pm on May 27, 2017 Permalink | Reply
    Tags: , , , , Bubbles from reionization at the cosmic dawn, , , SKA - Square Kilometre Array   

    From astrobites: “Bubbles from reionization at the cosmic dawn” 

    Astrobites bloc

    Astrobites

    Title: Dark-ages reionization & galaxy formation simulation XII: Bubbles at dawn
    Authors: Paul Geil, Simon Mutch, Gregory Poole, Alan Duffy, Andrei Mesinger, and Stuart Wyithe
    First Author’s Institution: University of Melbourne, Parkville, Victoria, Australia

    Status: Submitted to MNRAS, open access

    The early universe encompasses many scarcely understood phenomena both cosmological and astrophysical that we hope to begin exploring. This can be made possible by looking at the highly redshifted 21cm emission (see here for why this emission happens) from neutral hydrogen which puts these observations from the cosmic dawn relevant to today’s astrobite into the radio frequency range of 100-140 MHz. But this signal is notoriously faint, and requires some of the most sensitive instruments ever designed to observe it. Currently this is an emerging field where most of the instruments with the necessary sensitivity are only now entering the development stage. This certainly won’t stop us from understanding the potential pitfalls we may encounter along the way in measuring the early universe. We can of course anticipate how well we can detect this signal through simulations of the 21cm emission and our next generation radio telescopes.

    Cosmic Dawn and Galactic Reionization Bubbles

    When the first galaxies began to form they also began to emit UV radiation. This UV radiation reionized the surrounding neutral hydrogen, which means that it can no longer emit the 21cm emission. From our perspective when observing this we see large spherical holes (bubbles) begin to form over time, making a ‘Swiss cheese’-like effect at the largest scales. To make up for a lack of bubble observations, simulations of bubble formation from the Dark ages Reionization & Galaxy Formation Simulation (DRAGONS) (for an example see Fig. 1) were created.

    2
    Fig 1: Example of two galaxies with similar luminosities and solar mass from the DRAGON simulation. The progression of reionization of the galaxies is seen in the form of growing bubble size over redshift.

    Using information about mean bubble size and luminosity from DRAGONS, a relationship between the two can be found. This helps us in sampling appropriate galaxies to survey from the future Wide-Field Infrared Survey Telescope High Latitude Survey (WFIRST-HLS).

    NASA/WFIRST

    Fig 2. shows that the mean bubble size \bar{R}, increases linearly with luminosity. (Another example of associating bubble size and luminosity can be seen in this astrobite.)

    3
    Fig. 2: The authors show through simulation of reionization bubbles around galaxies that they have a linear relationship between the mean bubble size \bar{R} and the UV magnitude M_{UV}

    1cm Bubble Observing with the SKA

    The Square Kilometer Array (SKA) is an upcoming radio interferometer array located in South Africa and Western Australia.

    SKA-Square Kilometer Array


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


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

    It will consist of 1 sq. km of collecting area, making it the most sensitive array to ever exist, and a perfect instrument for observing the 21cm signal. Observation of the 21cm signal is dependent on the differential brightness temperature, \delta T_b.

    \delta T_b \propto x_{HI}(1+\delta)(1 – \frac{T_{\gamma}}{T_{S}})

    The differential brightness temperature depends on the dark matter over-density \delta (small fluctuations in the density), the spin temperature T_S, the CMB temperature T_{\gamma}, and the fraction of neutral hydrogen x_{HI}. It’s important to note that \delta T_b is spatially dependent, as both \delta and x_{HI} depend on position.

    For simulating the observation of the 21cm differential brightness temperature from the cosmic dawn, they use the SKA1-Low specifications which determine the sensitivity (see here for some basic interferometry) and observational hours required . But the sensitivity of the SKA isn’t enough, so stacking spectra (averaging observations over frequency) must be used. By focusing on high redshift galaxies (z > 9) predicted from the WFIRST-HLS, and stacking future SKA1-Low observations centered on these galaxies, the bubbles from reionization should be observable. An example of how likely these bubbles can be measured is seen in Fig. 3, which shows that the signal to noise ratio (SNR) grows considerably for stacking 100+ galaxy observations in the case where T_{S} >> T_{\gamma} (right).

    4
    Fig. 3: The SNR for observing reionization bubbles increases if more spectra are stacked (100,200,300) and if \delta T_b is saturated (right), which means \delta T_b >> T_{\gamma}.

    It appears from the author’s results that imaging individual bubbles from reionization doesn’t seem too likely as there is too much uncertainty in redshift and a high sensitivity required from the radio interferometer. But the technique the authors of today’s astrobite describe of stacking spectra over many galaxies does appear to provide that extra sensitivity for a measurement. There is also the big caveat of this being an ideal case, because our observations of the early universe are troubled by bright galactic and extragalactic foregrounds. The work in this astrobite also demonstrates that making a measurement of reionization and its characteristic bubbles may rely on a synthesized approach e.g. using both 21cm and near infrared observations.

    See the full article here .

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    What do we do?

    Astrobites is a daily astrophysical literature journal written by graduate students in astronomy. Our goal is to present one interesting paper per day in a brief format that is accessible to undergraduate students in the physical sciences who are interested in active research.
    Why read Astrobites?

    Reading a technical paper from an unfamiliar subfield is intimidating. It may not be obvious how the techniques used by the researchers really work or what role the new research plays in answering the bigger questions motivating that field, not to mention the obscure jargon! For most people, it takes years for scientific papers to become meaningful.
    Our goal is to solve this problem, one paper at a time. In 5 minutes a day reading Astrobites, you should not only learn about one interesting piece of current work, but also get a peek at the broader picture of research in a new area of astronomy.

     
  • richardmitnick 1:20 pm on May 18, 2017 Permalink | Reply
    Tags: APEX Low-redshift Legacy Survey of MOlecular Gas, , , , , , SKA - Square Kilometre Array   

    From SKA: “International team completes large survey of gas in nearby galaxies” 

    SKA Square Kilometer Array

    SKA

    An international team of investigators led by Dr. Claudia Cicone (INAF – Astronomical Observatory of Brera), Dr. Matt Bothwell (University of Cambridge) and with the SKA Organisation Project Scientist Dr. Jeff Wagg as principal investigator have found the spectra of the carbon monoxide emission line in a sample of small but nearby galaxies and found that the most massive galaxies form stars and are rich in metals.

    1
    The 12m APEX ESO telescope, located on the plateau of Chajnantor in Chile, at 5000m altitude.

    The team, comprising investigators from Italy, the UK, Germany, Chile and China have completed a large survey of molecular gas in nearby galaxies using the 12m APEX telescope in Chile. The APEX Low-redshift Legacy Survey of MOlecular Gas (ALLSMOG, PI: Dr. Jeff Wagg) has observed the Carbon Monoxide (CO) molecule in a sample of 97 galaxies in the local Universe. The ALLSMOG data provide important information on the cold molecular gas content of these galaxies which have been well characterised in terms of their star-formation rates, gas-phase metallicities and atomic HI gas masses.

    ALLSMOG is an ESO observing program conceived by Dr. Jeff Wagg to study the molecular gas through the carbon monoxide emission line with the telescope Atacama Pathfinder Experiment (Apex), a collaboration between the Max Planck Institute for Radio Astronomy (MPIfR), the Onsala Space Observatory (Oso) and ESO, which is located on the plain of Chajnantor at 5000 meters above sea level, in the Chilean Andes.

    The article The final release date of ALLSMOG: a survey of CO in typical local low-M star-forming galaxies published today in the journal Astronomy & Astrophysics includes observations of 97 galaxies, 88 of whom studied with Apex (for more than 300 hours of observation from summer 2013 to winter 2015/2016) and 9 with the telescope of the Institute of millimetric radio astronomy (Iram) to Pico Veleta, Spain (between 2014 and 2015).

    IRAM 30m Radio telescope, on Pico Veleta in the Spanish Sierra Nevada

    The survey is the first major campaign ALLSMOG systematic observation of carbon monoxide extragalactic made with Apex telescope.

    “The ALLSMOG survey is the first large systematic extragalactic survey of CO ever conducted with the APEX telescope”, says Claudia Cicone, a Marie Skłodowska-Curie fellow at INAF- Osservatorio Astronomico di Brera. “Our research has an enormous legacy value because the entire scientific community can exploit our data. We really hope our efforts will stimulate new ideas and results.”

    “For all the galaxies in our sample we have additional information on their physical properties from optical observations and on their atomic gas content (HI) from radio observations of the HI21cm line published in previous studies and by other teams. We have created a real identikit of these galaxies which allows us to study the relations between the molecular gas and their other physical properties.”

    “In the near future, multi-wavelength galaxy studies like this will be greatly enhanced by data from the SKA telescope and its precursors such as ASKAP and MeerKAT”, says Dr. Jeff Wagg.

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

    SKA Meerkat telescope, 90 km outside the small Northern Cape town of Carnarvon, SA

    “While the SKA precursors are expected to detect more than half a million galaxies in HI line emission, these sample sizes have the potential to increase by nearly an order of magnitude when the SKA1-mid telescope comes online.”

    SKA1-mid is the dish array telescope to be built in South Africa that will be operating in the 350Mhz -14Ghz frequency range, complementary to the low-frequency telescope (so-called SKA1-low) to be built in Australia. Although SKA1-mid and the SKA precursors do not have the frequency coverage needed to measure the molecular gas in nearby galaxies, they will be able to detect the atomic gas through the 21cm atomic HI line transition.

    “Quantifying the total gas content (atomic and molecular) of significant samples of galaxies out to large distances remains one of the crucial elements needed for a full understanding of galaxy formation”, concludes Dr. Jeff Wagg.

    See the full article here .

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    SKA Banner

    SKA CSIRO  Pathfinder Telescope
    SKA ASKAP Pathefinder Telescope

    SKA Meerkat telescope
    SKA Meerkat Telescope

    SKA Murchison Widefield Array
    SKA Murchison Wide Field Array

    About SKA

    The Square Kilometre Array will be the world’s largest and most sensitive radio telescope. The total collecting area will be approximately one square kilometre giving 50 times the sensitivity, and 10 000 times the survey speed, of the best current-day telescopes. The SKA will be built in Southern Africa and in Australia. Thousands of receptors will extend to distances of 3 000 km from the central regions. The SKA will address fundamental unanswered questions about our Universe including how the first stars and galaxies formed after the Big Bang, how dark energy is accelerating the expansion of the Universe, the role of magnetism in the cosmos, the nature of gravity, and the search for life beyond Earth. Construction of phase one of the SKA is scheduled to start in 2016. The SKA Organisation, with its headquarters at Jodrell Bank Observatory, near Manchester, UK, was established in December 2011 as a not-for-profit company in order to formalise relationships between the international partners and centralise the leadership of the project.

    The Square Kilometre Array (SKA) project is an international effort to build the world’s largest radio telescope, led by SKA Organisation. The SKA will conduct transformational science to improve our understanding of the Universe and the laws of fundamental physics, monitoring the sky in unprecedented detail and mapping it hundreds of times faster than any current facility.

    Already supported by 10 member countries – Australia, Canada, China, India, Italy, New Zealand, South Africa, Sweden, The Netherlands and the United Kingdom – SKA Organisation has brought together some of the world’s finest scientists, engineers and policy makers and more than 100 companies and research institutions across 20 countries in the design and development of the telescope. Construction of the SKA is set to start in 2018, with early science observations in 2020.

     
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