From ALMA: “Spiraling giants: witnessing the birth of a massive binary star system”

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

From ALMA

18 March, 2019

Nicolás Lira
Education and Public Outreach Coordinator
Joint ALMA Observatory, Santiago – Chile
Phone: +56 2 2467 6519
Cell phone: +56 9 9445 7726
Email: nicolas.lira@alma.cl

Jens Wilkinson
RIKEN Global Communications
Japan
Phone: +81-(0)48-462-1225
Email: pr@riken.jp

Masaaki Hiramatsu
Education and Public Outreach Officer, NAOJ Chile
Observatory
, Tokyo – Japan
Phone: +81 422 34 3630
Email: hiramatsu.masaaki@nao.ac.jp

Calum Turner
ESO Assistant Public Information Officer
Garching bei München, Germany
Phone: +49 89 3200 6670
Email: calum.turner@eso.org

Charles E. Blue
Public Information Officer
National Radio Astronomy Observatory Charlottesville, Virginia – USA
Phone: +1 434 296 0314
Cell phone: +1 202 236 6324
Email: cblue@nrao.edu

ALMA’s view of the IRAS-07299 star-forming region and the massive binary system at its center. The background image shows dense, dusty streams of gas (shown in green) that appear to be flowing towards the center. Gas motions, as traced by the methanol molecule, that are towards us are shown in blue; motions away from us in red. The inset image shows a zoom-in view of the massive forming binary, with the brighter, primary protostar moving toward us is shown in blue and the fainter, secondary protostar moving away from us shown in red. The blue and red dotted lines show an example of orbits of the primary and secondary spiraling around their center of mass (marked by the cross).

Movie composed of images taken by ALMA showing the gas streams, as traced by the methanol molecule, with different line-of-sight color-coded velocities, around the massive binary protostar system. The grey background image shows the overall distribution, from all velocities, of dust emission from the dense gas streams.

Scientists from the RIKEN Cluster for Pioneering Research in Japan,the Chalmers University of Technology in Sweden,and the University of Virginia in the USA and collaborators used the Atacama Large Millimeter/submillimeter Array (ALMA) to observe a molecular cloud that is collapsing to form two massive protostars that will eventually become a binary star system.

While it is known that most massive stars possess orbiting stellar companions it has been unclear how this comes about – for example, are the stars born together from a common spiraling gas disk at the center of a collapsing cloud, or do they pair up later by chance encounters in a crowded star cluster.

Understanding the dynamics of forming binaries has been difficult because the protostars in these systems are still enveloped in a thick cloud of gas and dust that prevents most light from escaping. Fortunately, it is possible to see them using radio waves, as long as they can be imaged with sufficiently high spatial resolution.

In the current research, published in Nature Astronomy, the researchers led by Yichen Zhang of the RIKEN Cluster for Pioneering Research and Jonathan C. Tan at the Chalmers University,and the University of Virginia, used ALMA to observe, at high spatial resolution, a star-forming region known as IRAS07299-1651, which is located 1.68 kiloparsecs, or about 5,500 light years, away.

The observations showed that already at this early stage, the cloud contains two objects, a massive “primary” central star and another “secondary” forming star, also of high mass. For the first time, the research team was able to use these observations to deduce the dynamics of the system. The observations showed that the two forming stars are separated by a distance of about 180 astronomical units—a unit approximately the distance from the earth to the sun. Hence, they are quite far apart. They are currently orbiting each other with a period of at most 600 years and have a total mass at least 18 times that of our Sun.

According to Zhang, “This is an exciting finding because we have long been perplexed by the question of whether stars form into binaries during the initial collapse of the star-forming cloud or whether they are created during later stages. Our observations clearly show that the division into binary stars takes place early on, while they are still in their infancy.”

Another finding of the study was that the binary stars are being nurtured from a common disk fed by the collapsing cloud and favoring a scenario in which the secondary star of the binary formed as a result of fragmentation of the disk originally around the primary. This allows the initially smaller secondary protostar to “steal” infalling matter from its sibling and eventually they should emerge as quite similar “twins”.

Tan adds, “This is an important result for understanding the birth of massive stars. Such stars are important throughout the universe, not least for producing, at the ends of their lives, the heavy elements that make up our Earth and are in our bodies.”

Zhang concludes, “What is important now is to look at other examples to see whether this is a unique situation or something that is common for the birth of all massive stars.”

Additional Information

RIKEN is Japan’s largest research institute for basic and applied research. Over 2500 papers by RIKEN researchers are published every year in leading scientific and technology journals covering a broad spectrum of disciplines including physics, chemistry, biology, engineering, and medical science. RIKEN’s research environment and a strong emphasis on interdisciplinary collaboration and globalization have earned a worldwide reputation for scientific excellence.

At the RIKEN Pioneering Research Cluster, outstanding researchers with rich research achievements and strong leadership abilities serve as leaders of Chief Scientist Laboratories, from where they carry out innovative fundamental research, pioneer new research fields, and carry on research that crosses disciplinary and organizational barriers.

See the full article here .

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

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

From insideHPC: “In a boon for HPC, Founding Members Sign SKA Observatory Treaty”

From insideHPC

March 14, 2019

The initial signatories of the SKA Observatory Convention. From left to right: UK Ambassdor to Italy Jill Morris, China’s Vice Minister of Science and Technology Jianguo Zhang, Portugal’s Minister for Science, Technology and Higher Education Manuel Heitor, Italian Minister of Education, Universities and Research Marco Bussetti, South Africa’s Minister of Science and Technology Mmamoloko Kubayi-Ngubane, the Netherlands Deputy Director of the Department for Science and Research Policy at the Ministry of Education, Culture and Science Oscar Delnooz, and Australia’s Ambassdor to Italy Greg French (Credit: SKA Organization)

Earlier this week, countries involved in the Square Kilometre Array (SKA) Project came together in Rome to sign an international treaty establishing the intergovernmental organization that will oversee the delivery of the world’s largest radio telescope.

SKA Square Kilometer Array

Ministers, Ambassadors and other high-level representatives from over 15 countries have gathered in the Italian capital for the signature of the treaty which establishes the Square Kilometre Array Observatory (SKAO), the intergovernmental organization (IGO) tasked with delivering and operating the SKA.

“Today we are particularly honored to sign, right here at the Ministry of Education, University and Research, the Treaty for the establishment of the SKA Observatory” Italian Minister of Education Marco Bussetti who presided over the event, said. “A signature that comes after a long phase of negotiations, in which our country has played a leading role. The Rome Convention testifies the spirit of collaboration that scientific research triggers between countries and people around the world, because science speaks all the languages of the planet and its language connects the whole world. This Treaty – he added – is the moment that marks our present and our future history, the history of science and knowledge of the Universe. The SKA project is the icon of the increasingly strategic role that scientific research has taken on in contemporary society. Research is the engine of innovation and growth: knowledge translates into individual and collective well-being, both social and economic. Participating in the forefront of such an extensive and important international project is a great opportunity for the Italian scientific community, both for the contribution that our many excellences can give and for sharing the big amount of data that SKA will collect and redistribute.”

Seven countries signed the treaty today, including Australia, China, Italy, The Netherlands, Portugal, South Africa and the United Kingdom. India and Sweden, who also took part in the multilateral negotiations to set up the SKA Observatory IGO, are following further internal processes before signing the treaty. Together, these countries will form the founding members of the new organisation.

Dr. Catherine Cesarsky, Chair of the SKA Board of Directors, added “Rome wasn’t built in a day. Likewise, designing, building and operating the world’s biggest telescope takes decades of efforts, expertise, innovation, perseverance, and global collaboration. Today we’ve laid the foundations that will enable us to make the SKA a reality.”

“…SKA will be the largest science facility on the planet, with infrastructure spread across three continents on both hemispheres. Its two networks of hundreds of dishes and thousands of antennas will be distributed over hundreds of kilometres in Australia and South Africa, with the Headquarters in the United Kingdom.”

SKA South Africa

Together with facilities like the James Webb Space Telescope, CERN’s Large Hadron Collider, the LIGO gravitational wave detector, the new generation of extremely large optical telescopes and the ITER fusion reactor, the SKA will be one of humanity’s cornerstone physics machines in the 21st century.

NASA/ESA/CSA Webb Telescope annotated

LHC

CERN map

CERN LHC Tunnel

CERN LHC particles

MIT /Caltech Advanced aLigo new bloc

ITER Tokamak in Saint-Paul-lès-Durance, which is in southern France

Prof. Philip Diamond, Director-General of the SKA Organization which has led the design of the telescope added: “Like Galileo’s telescope in its time, the SKA will revolutionize how we understand the world around us and our place in it. Today’s historic signature shows a global commitment behind this vision, and opens up the door to generations of ground-breaking discoveries.”

It will help address fundamental gaps in our understanding of the Universe, enabling astronomers from its participating countries to study gravitational waves and test Einstein’s theory of relativity in extreme environments, investigate the nature of the mysterious fast radio bursts, improve our understanding of the evolution of the Universe over billions of years, map hundreds of millions of galaxies and look for signs of life in the Universe.

Two of the world’s fastest supercomputers* will be needed to process the unprecedented amounts of data emanating from the telescopes, with some 600 petabytes expected to be stored and distributed worldwide to the science community every year, or the equivalent of over half a million laptops worth of data.

Close to 700 million euros worth of contracts for the construction of the SKA will start to be awarded from late 2020 to companies and providers in the SKA’s member countries, providing a substantial return on investment for those countries. Spinoffs are also expected to emerge from work to design and build the SKA, with start-ups already being created out of some of the design work and impact reaching far beyond astronomy.

In this video from the Disruptive Technologies Panel at the HPC User Forum, Peter Braam from Cambridge University presents: Processing 1 EB per Day for the SKA Radio Telescope.

Over 1,000 engineers and scientists in 20 countries have been involved in designing the SKA over the past five years, with new research programs, educational initiatives and collaborations being created in various countries to train the next generation of scientists and engineers.

Guests from Canada, France, Malta, New Zealand, the Republic of Korea, Spain and Switzerland were also in attendance to witness the signature and reaffirmed their strong interest in the project. They all confirmed they are making their best efforts to prepare the conditions for a future decision of participation of their respective country in the SKA Observatory.

The signature concludes three and a half years of negotiations by government representatives and international lawyers, and kicks off the legislative process in the signing countries, which will see SKAO enter into force once five countries including all three hosts have ratified the treaty through their respective legislatures.

SKAO becomes only the second intergovernmental organization dedicated to astronomy in the world, after the European Southern Observatory (ESO) [What about ESA and ALMA?].

*Not identified in the article. I have asked for the names and locations of the supercomputers.

See the full article here .

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Founded on December 28, 2006, insideHPC is a blog that distills news and events in the world of HPC and presents them in bite-sized nuggets of helpfulness as a resource for supercomputing professionals. As one reader said, we’re sifting through all the news so you don’t have to!

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From ALMA: “ALMA Observes the Formation Sites of Solar-System-like Planets”

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

From ALMA

2019.03.11

Researchers have spotted the formation sites of planets around a young star resembling our Sun. Two rings of dust around the star, at distances comparable to the asteroid belt and the orbit of Neptune in our Solar System, suggest that we are witnessing the formation of a planetary system similar to our own.

The Solar System is thought to have formed from a cloud of cosmic gas and dust 4.6 billion years ago. By studying young planetary systems forming around other stars, astronomers hope to learn more about our own origins.

Tomoyuki Kudo, an astronomer at the National Astronomical Observatory of Japan (NAOJ), and his team observed the young star DM Tau using the Atacama Large Millimeter/submillimeter Array (ALMA). Located 470 light-years away in the constellation Taurus, DM Tau is about half the mass of the Sun and estimated to be three to five million years old.

“Previous observations inferred two different models for the disk around DM Tau,” said Kudo. “Some studies suggested the radius of the ring is about where the Solar System’s asteroid belt would be. Other observations put the size out where Neptune would be. Our ALMA observations provided a clear answer: both are right. DM Tau has two rings, one at each location.”

The researchers found a bright patch in the outer ring. This indicates a local concentration of dust, which would be a possible formation site for a planet like Uranus or Neptune.

“We are also interested in seeing the details in the inner region of the disk, because the Earth formed in such an area around the young Sun,” commented Jun Hashimoto, a researcher at the Astrobiology Center, Japan. “The distribution of dust in the inner ring around DM Tau will provide crucial information to understand the origin of planets like Earth.”

ALMA image of the dusty disk around the young star DM Tau. You can see two concentric rings where planets may be forming. Credit: ALMA (ESO/NAOJ/NRAO), Kudo et al.

Artist’s impression of the disk around a young star DM Tau. Credit: NAOJ

Paper and the research team
These results were published as Kudo et al. “A Spatially Resolved au-scale Inner Disk around DM Tau” in The Astrophysical Journal in November 2018 and presented at the annual meeting of the Astronomical Society of Japan in March 2019.

The research team members are:
Tomoyuki Kudo (National Astronomical Observatory of Japan), Jun Hashimoto (Astrobiology Center), Takayuki Muto (Kogakuin University), Hauyu Baobab Liu (European Southern Observatory), Ruobing Dong (University of Victoria), Yasuhiro Hasegawa (California Institute of Technology)

This research was supported by JSPS KAKENHI (Nos. 17K14258, 17K14244, 26800106, 15H02074, 17H01103）and NASA Jet Propulsion Laboratory

See the full article here .

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

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

From ALMA: “Hiding Black Hole Found”

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

From ALMA

28 February, 2019

Valeria Foncea
Education and Public Outreach Officer
Joint ALMA Observatory Santiago – Chile
Phone: +56 2 2467 6258
Cell phone: +56 9 7587 1963
Email: valeria.foncea@alma.cl

Masaaki Hiramatsu
Education and Public Outreach Officer, NAOJ Chile
Observatory
, Tokyo – Japan
Phone: +81 422 34 3630
Email: hiramatsu.masaaki@nao.ac.jp

Calum Turner
ESO Assistant Public Information Officer
Garching bei München, Germany
Phone: +49 89 3200 6670
Email: calum.turner@eso.org

Charles E. Blue
Public Information Officer
National Radio Astronomy Observatory Charlottesville, Virginia – USA
Phone: +1 434 296 0314
Cell phone: +1 202 236 6324
Email: cblue@nrao.edu

Artist’s impression of a gas cloud swirling around a black hole. Credit: NAOJ

Astronomers have detected a stealthy black hole from its effects on an interstellar gas cloud. This intermediate mass black hole is one of over 100 million quiet black holes expected to be lurking in our galaxy. These results provide a new method to search for other hidden black holes and help us understand the growth and evolution of black holes.

Black holes are objects with such strong gravity that everything, including light, is sucked in and cannot escape. Because black holes do not emit light, astronomers must infer their existence from the effects their gravity produce in other objects. Black holes range in mass from about 5 times the mass of the Sun to supermassive black holes millions of times the mass of the Sun. Astronomers think that small black holes merge and gradually grow into large ones, but no one had ever found an intermediate mass, hundreds or thousands of times the mass of the Sun.

A research team led by Shunya Takekawa at the National Astronomical Observatory of Japan noticed HCN–0.009–0.044, a gas cloud moving strangely near the center of the Galaxy 25,000 light-years away from Earth in the constellation Sagittarius. They used ALMA (Atacama Large Millimeter/submillimeter Array) to perform high resolution observations of the cloud and found that it is swirling around an invisible massive object.

Takekawa explains, “Detailed kinematic analyses revealed that an enormous mass, 30,000 times that of the Sun, was concentrated in a region much smaller than our Solar System. This and the lack of any observed object at that location strongly suggests an intermediate-mass black hole. By analyzing other anomalous clouds, we hope to expose other quiet black holes. ”

Tomoharu Oka, a professor at Keio University and coleader of the team, adds, “It is significant that this intermediate mass black hole was found only 20 light-years from the supermassive black hole at the Galactic center. In the future, it will fall into the supermassive black hole; much like gas is currently falling into it. This supports the merger model of black hole growth.”

These results were published as Takekawa et al. “Indication of Another Intermediate-mass Black Hole in the Galactic Center” in The Astrophysical Journal Letters on January 20, 2019.

See the full article here .

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Please help promote STEM in your local schools.

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

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

From ALMA: “ALMA Differentiates Two Birth Cries from a Single Star”

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

From ALMA

26 February, 2019

Valeria Foncea
Education and Public Outreach Officer
Joint ALMA Observatory Santiago – Chile
Phone: +56 2 2467 6258
Cell phone: +56 9 7587 1963
Email: valeria.foncea@alma.cl

Masaaki Hiramatsu
Education and Public Outreach Officer, NAOJ Chile
Observatory
, Tokyo – Japan
Phone: +81 422 34 3630
Email: hiramatsu.masaaki@nao.ac.jp

Charles E. Blue
Public Information Officer
National Radio Astronomy Observatory Charlottesville, Virginia – USA
Phone: +1 434 296 0314
Cell phone: +1 202 236 6324
Email: cblue@nrao.edu

Calum Turner
ESO Assistant Public Information Officer
Garching bei München, Germany
Phone: +49 89 3200 6670
Email: calum.turner@eso.org

ALMA image of the protostar MMS5/OMC-3. The protostar is located at the center and the gas streams are ejected to the east and west (left and right). The slow outflow is shown in orange and the fast jet is shown in blue. It is obvious that the axes of the outflow and jet are misaligned. Credit: ALMA (ESO/NAOJ/NRAO), Matsushita et al.

Astronomers have unveiled the enigmatic origins of two different gas streams from a baby star. Using ALMA, they found that the slow outflow and the high speed jet from a protostar have misaligned axes and that the former started to be ejected earlier than the latter. The origins of these two flows have been a mystery, but these observations provide telltale signs that these two streams were launched from different parts of the disk around the protostar.

Stars in the Universe have a wide range of masses, ranging from hundreds of times the mass of the Sun to less than a tenth of that of the Sun. To understand the origin of this variety, astronomers study the formation process of the stars, that is the aggregation of cosmic gas and dust.

Baby stars collect the gas with their gravitational pull, however, some of the material is ejected by the protostars. This ejected material forms a stellar birth cry which provides clues to understand the process of mass accumulation.

Yuko Matsushita, a graduate student at Kyushu University and her team used ALMA to observe the detailed structure of the birth cry from the baby star MMS5/OMC-3 and found two different gaseous flows: a slow outflow and a fast jet. There have been a handful of examples with two flows seen in radio waves, but MMS5/OMC-3 is exceptional.

“Measuring the Doppler shift of the radio waves, we can estimate the speed and lifetime of the gas flows,” said Matsushita, the lead author of the research paper that appeared in the Astrophysical Journal. “We found that the jet and outflow were launched 500 years and 1300 years ago, respectively. These gas streams are quite young.”

More interestingly, the team found that the axes of the two flows are misaligned by 17 degrees. The axis of the flows can be changed over long time periods due to the precession of the central star. But in this case, considering the extreme youth of the gas streams, researchers concluded that the misalignment is not due to precession but is related to the launching process.

There are two competing models for the formation mechanism of the protostellar outflows and jets. Some researchers assume that the two streams are formed independently in different parts of the gas disk around the central baby star, while others propose that the collocated jet is formed first, then it entrains the surrounding material to form the slower outflows. Despite extensive research, astronomers had not yet reached a conclusive answer.

A misalignment in the two flows could occur in the ‘independent model,’ but is difficult in the ‘entrainment model.’ Moreover, the team found that the outflow was ejected considerably earlier than the jet. This clearly backs the ‘independent model.’

“The observation well matches the result of my simulation,” said Masahiro Machida, a professor at Kyushu University. A decade ago, he performed pioneering simulation studies using a supercomputer operated by the National Astronomical Observatory of Japan. In the simulation, the wide-angle outflow is ejected from the outer area of the gaseous disk around a prototar, while the collimated jet is launched independently from the inner area of the disk. Machida continues, “An observed misalignment between the two gas streams may indicate that the disk around the protostar is warped.”

“ALMA’s high sensitivity and high angular resolution will enable us to find more and more young, energetic outflow-and-jet-systems like MMS 5/OMC-3,” said Satoko Takahashi, an astronomer at the National Astronomical Observatory of Japan and the Joint ALMA Observatory and co-author of the paper. “They will provide clues to understand the driving mechanisms of outflows and jets. Moreover studying such objects will also tell us how the mass accretion and ejection processes work at the earliest stage of star formation.”
Additional Information

These observation results were published as Matsushita et al. “Very Compact Extremely High Velocity Flow toward MMS 5 / OMC-3 Revealed with ALMA” in The Astrophysical Journal issued in February 2019.

The research team members are:

Yuko Matsushita (Kyushu University), Satoko Takahashi (Joint ALMA Observatory/National Astronomical Observatory of Japan/SOKENDAI), Masahiro Machida (Kyushu University), and Koji Tomisaka (National Astronomical Observatory of Japan/SOKENDAI)

This research was supported by JSPS KAKENHI (No. 17K05387, 17H06360, 17H02869, 15K05032) and the Science Visitor Program of the Joint ALMA Observatory.

See the full article here .

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Please help promote STEM in your local schools.

Stem Education Coalition

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

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

From SKA: “SKA’s Infrastructure consortia complete their detailed design work for the SKA sites”

From SKA

25 February 2019

The two engineering consortia tasked with designing all the essential infrastructure for the SKA sites in Australia and South Africa have formally concluded their work, bringing to a close nearly five years of collaboration both within and between the consortia.

Infrastructure Australia (INAU) and Infrastructure South Africa (INSA) were each led by institutions with great expertise in radio astronomy projects: Australia’s CSIRO, which designed, built and operates the SKA precursor telescope ASKAP at its Murchison Radio-astronomy Observatory (MRO)…

Australian Square Kilometre Array Pathfinder (ASKAP) is a radio telescope array located at Murchison Radio-astronomy Observatory (MRO) in the Australian Mid West. ASKAP consists of 36 identical parabolic antennas, each 12 metres in diameter, working together as a single instrument with a total collecting area of approximately 4,000 square metres.

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

…and the South African Radio Astronomy Observatory (SARAO), which designed, built and operates the SKA precursor telescope MeerKAT. Industry partners also played key roles in both consortia*, while the European Union’s Research and Innovation programme Horizon 2020 awarded an additional €5M to conduct further work at both sites and at the SKA Global Headquarters in the UK.

SKA Meerkat telescope, South African design

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

The consortia were responsible for designing everything required to be able to deploy and operate the SKA in its two host countries, from roads, buildings, power, to RFI shielding, water and sanitation. Both CSIRO and SARAO developed valuable expertise from delivering the two precursor telescopes, which they applied to their work designing the SKA’s site infrastructure.

“This is the culmination of many years of development on both sites in preparation for the start of construction of the SKA,” says Gary Davis, the SKA’s Head of Operations Planning and chair of the review panel. “Both consortia have done a stellar job in collaboration with one another to design the crucial infrastructure that’ll support the SKA.”

A major goal of the two consortia was to collaborate with each other in order to develop a common engineering approach, share knowledge and provide lessons learnt through the design and delivery of SKA precursors.

“From the start we developed what we called the GIG, the good ideas group” says Ant Schinckel, Infrastructure Australia’s Consortium Lead. “Our engineers would continuously engage with each other to discuss issues in both countries and find common solutions that could be applied to both sites” complements Tracy Cheetham, Infrastructure South Africa’s Consortium Lead.

“I’d like to thank both teams for their excellent work” said Martin Austin, the SKA’s Infrastructure Project Manager “The quality of the design and their approach to safety means that we can now carry this work forward with a high degree of confidence, supported by both CSIRO and SARAO and their industry partners.”

INAU and INSA formed part of a global effort by 12 international engineering consortia, representing 500 engineers and scientists in 20 countries. Nine of the consortia focused on the SKA’s core elements, while three others were tasked with developing advanced instrumentation.

In 2018 and 2019 the nine consortia are having their Critical Design Reviews (CDRs), during which the proposed design must meet the project’s tough engineering requirements to be approved, before a construction proposal for the SKA can be developed.

In June and July 2018, both infrastructure consortia had successful CDRs and subsequently made the final refinements to their designs. With that work complete the consortia now formally disband, although the SKA will continue to work closely with former members in the months ahead as the overall System CDR approaches, to ensure that the infrastructure design aligns with all of the other components.

*Infrastructure Australia consortium members included the Commonwealth Scientific and Industrial Research Organisation (CSIRO), Aurecon Australia and Rider Levett Bucknall.

Infrastructure South Africa consortium members included the South African Radio Astronomy Observatory (SARAO), Aurecon South Africa and HHO Africa.

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

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 Arraywill 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.

From SKA: “Canadian-led Central Signal Processor consortium successfully concludes SKA design work”

From SKA

Members of the Central Signal Processor consortium at SKA Global Headquarters during the Critical Design Review in September 2018 (Credit: SKA Organisation)

20 February 2019

The international Central Signal Processor (CSP) consortium has concluded its design work on the SKA, marking the end of five years’ work comprised of 11 signatory members from 8 countries with more than 10 additional participating organisations.

The consortium, led by the National Research Council of Canada (NRC)*, has designed the elements that will together form the “processing heart” of the SKA. The CSP is the first stage of processing for the masses of digitised astronomical signals collected by the telescope’s receivers. It’s where the correlation and beamforming takes place to make sense of the jumble of signals, before the data is sent onwards to the Science Data Processor. At that stage, the data is ready to be turned into detailed astronomical images of the sky.

The CSP includes the Pulsar Search and Timing sub-elements, which enable astronomers to detect and characterise pulsars and fast transients. This will facilitate the most comprehensive and ambitious survey yet to detect all pulsars in our own galaxy as well as the first extragalactic pulsars. The Pulsar Search sub-element is based on a hybrid architecture of Graphics Processing Units (GPUs) and Field Programmable Gate Arrays (FPGA) computing boards. The design team was led by the University of Manchester (UK), University of Oxford (UK) and the Max Planck Institute for Radio Astronomy (Germany) supported by input from INAF (Italy), New Zealand Alliance, STFC ATC Edinburgh (UK), and ASTRON (the Netherlands). The Pulsar Timing sub-element is based on GPUs. The design team consisted of participants from Swinburne University of Technology (Australia) and the New Zealand Alliance.

Low CBF liquid-cooled Perentie Gemini Processing Board (left), Mid CBF Air-cooled TALON-DX Processing Board (right).

As part of their work, the consortium designed the FPGA computing boards that will perform correlation and beamforming (CBF) on the signals from the SKA. The CBF for the SKA-mid telescope -to be located in South Africa- is based on Intel FPGA technology and was led by the NRC with support from MDA, a Maxar Technologies company, AUT University (New Zealand), and INAF. The CBF for the SKA-low telescope -to be located in Australia- is based on Xilinx technology, was led by CSIRO with support from ASTRON and AUT University. Hundreds of these boards are required to meet the demanding processing requirements.

The Local Monitoring and Control sub-element was led by the NRC with contributions from MDA, INAF, and NCRA (India).

The consortium was given a full pass by the review panel during the CSP Critical Design Review (CDR) in September, the first SKA engineering consortium to receive this result. With very few actions required following the review, the consortium has now concluded its work.

“This is an extremely complex system – it has to process as many bits every 15 seconds as all the bits that are flowing through the global internet today,” said Consortium Lead Luc Simard of the NRC. “That’s a huge processing challenge at a site with limited electrical power and cooling power, and we have to fit a lot of hardware in a tight, restricted environment. To meet this challenge we needed a team of the highest quality – we have the best of the best and working with them has been a real honour. I’m really thankful for all their work.”

The consortium was formed in late 2013 as one of 12 international engineering consortia tasked with designing the SKA, a global effort representing 500 engineers in 20 countries. Nine consortia focused on core elements, while three developed advanced instrumentation for the telescope. The nine consortia are now at CDR stage, where an expert panel examines each design proposal against the SKA’s stringent requirements.

Now that its work is complete the consortium formally disbands, although the SKA Organisation will work closely with participating countries to prepare for the overall System CDR and the development of the SKA construction proposal.

“What made the design challenge so difficult are the exacting requirements for a telescope to deliver SKA telescope transformational science,” said Philip Gibbs, SKA Organisation Project Manager for CSP. “The system has to meet observing requirements that may include imaging, as well as VLBI, and pulsar search and timing, all at the same time. As well as the power and space issues on site, we’ve naturally also been constrained by the cost involved in providing a solution.”

“To reach this point is a testament to the tremendous effort of all the institutions involved in designing CSP – my heartfelt thanks go to them. We look forward to continued collaboration as we progress down the road towards construction of the SKA.”

*The CSP Consortium Project Management Office was led by a collaboration between the NRC and MDA, a contracted industry partner. Active consortium members (signatories) at the conclusion of the work included: Netherlands Institute for Radio Astronomy (ASTRON), Commonwealth Scientific and Industrial Research Organisation (CSIRO) (Australia), Swinburne University of Technology (Australia), Max Planck Institute for Radio Astronomy (Germany), National Institute for Astrophysics (INAF) (Italy), New Zealand Alliance (AUT University, Massey University, University of Auckland, Compucon New Zealand and Open Parallel Ltd.), the Science and Technology Facilities Council (STFC) (UK), University of Manchester (UK), and University of Oxford (UK).

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 Arraywill 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.

From Medium: “Is J1420–0545 the largest galaxy ever discovered?”

From Medium

Jan 27, 2019
Graham Doskoch

An unassuming galaxy hides a secret 15 million light-years long.

If we could get high-quality optical images of J1420–0545, they might look like this photograph of its closer cousin, the giant radio galaxy 3C 236. This Hubble image only shows the galaxy’s core; radio telescopes reveal a much larger structure. Image credit: NASA/ESA.

The Milky Way is about 50 to 60 kiloparsecs in diameter — a moderately sized spiral galaxy.

Milky Way Galaxy Credits: NASA/JPL-Caltech/R. Hurt

It’s a few orders of magnitude larger than the smallest galaxies, ultra-compact dwarfs like M60–UCD1 that have most of their stars clustered in a sphere less than 50 to 100 parsecs across. At the extreme opposite end of the spectrum lie supergiant ellipticals, more formally known as cD galaxies, whose diffuse halos can be up to 1–2 megaparsecs wide. To put this in perspective, the Andromeda galaxy is 0.78 Mpc away.

Andromeda Galaxy Adam Evans

Andromeda Nebula Clean by Rah2005 on DeviantArt

This means that the 2-megaparsec-long stellar halo of IC 1101 — sometimes hailed as the largest known galaxy in the observable universe — could stretch from the Milky Way to Andromeda and then some.

IC 1101, possibly the largest known galaxy in the universe. Its diffuse halo might not look like much, but it extends about one megaparsec in each direction. Image credit: NASA/ESA/Hubble Space Telescope

Yet IC 1101 pales in comparison to another class of objects: radio galaxies. Radio galaxies are sources of strong synchrotron emission, radiation from particles being accelerated along curved paths by magnetic fields. Active galactic nuclei are the culprits, supermassive black holes accreting matter and sending out jets of energetic electrons. In most cases, these jets are hundreds of kiloparsecs in length, and some are even longer.

This week’s blog post talks about J1420–0545, currently the largest-known radio galaxy. To be more specific, it has the largest radio “cocoon” ever observed. These cocoons are structures formed by shocked plasma from the jets, which expands outward into the intergalactic medium (IGM) and encases the jets and the lobes they form. The entire radio structure around J1420–0545 is enormous, stretching 4.69 Mpc — 15 million light-years — from end to end. Read on to find out just how extraordinary this galaxy is and how we know so much about its enormous cocoon, despite knowing so little about the host galaxy itself.

Initial observations and slight surprise

J1420–0545 was discovered, like many unusual galaxies, in a survey scanning the sky. In particular, it showed up as two large radio lobes spaced 17.4′ apart on the FIRST and NVSS surveys observing at 1.4 GHz using the Very Large Array (VLA).

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

Follow-up observations made at Effelsberg and the Giant Metrewave Radio Telescope (GMRT) (Machalski et al. 2008) then confirmed that there was a radio-loud core located midway between them, and that it corresponded to a previously-known dim galaxy.

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

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

Fig. 1, Machalski et al. 2008. VLA/Effelsberg observations of J1020–0545 showed that the main sources of 1.4 GHz emission were two large radio-loud lobes and a weaker central source. The galaxy itself is in the crosshairs in the image, a speck among specks.

Redshift values for that galaxy were available (z~0.42–0.46), but had large uncertainties, so the team performed their own optical photometry at the Mount Suhora Observatory. The spectra derived from this proved useful in two ways. First, the spectroscopy allowed the team to figure out what sort of galaxy they were looking at. Unlike the radio lobes, the optical emission from the center couldn’t be resolved, and it wasn’t possible to image the galaxy in the same way that we could take a picture of, say, our neighbor Andromeda. Fortunately, there was a solution: The 4000 Å discontinuity.

Elliptical galaxies are typically old, having formed over time from mergers and collisions of smaller galaxies of varying types. Star formation levels are low, meaning that there are relatively few young, hot, blue stars compared to star-forming spiral and lenticular galaxies. Now, at wavelengths a bit shorter than 4000 Å, there is a drop-off in emission thanks to absorption by metals in stellar atmospheres. In most galaxies, hot stars fill in this gap, when present. However, in elliptical galaxies, there are few hot stars, and so there is a “discontinuity” in the spectra around 4000 Å.

The team found other spectral features corroborating the hypothesis that J1420–0545 is an elliptical galaxy. Now that they knew the sort of spectrum they expected to see, they could fit a model to it. Measurements of [O II] and Ca II absorption lines yielded a new redshift of z~0.03067, placing the object closer than originally thought. Since the redshift (and therefore the distance) was known, as well as the angular size of the radio cocoon, its size could be estimated — assuming that the inclination angle was 90°, as suggested by the weak emission from the core. A simple calculation showed that the jets must be 4.69 Mpc long.

How did it get so big?

A radio structure of this size isn’t unprecedented. The giant radio galaxy 3C 236 had already been discovered, and found to have a radio cocoon 4.4 Mpc in length. However, what was surprising about J1420–0545 wasn’t just its size, but its age. Best-fit models of the jet and ambient medium found the structure to have an age of about 47 million years; 3C 236, on the other hand, is thought to have been active for 110 million years — more than double that. So why is J1420–0545, a relatively young radio galaxy, so large?

Fig. 1, Carilli & Barthel 1995. A radio galaxy’s narrow jets are surrounded by a bow shock at the boundary with the intergalactic medium, as well as a radio cocoon.

The answer turned out to be the intergalactic medium itself, the hot plasma that fills the spaces between galaxies. The IGM at the center of the galaxy is lower than at the center of 3C 236 by about a factor of 20, meaning that the gas pressure opposing the jets’ expansion was correspondingly lower. The power of the AGN in J1420–0545 is also 50% greater than the AGN in 3C 236; this, combined with the substantially lower ambient IGM density, meant that the jets experienced much less resistance as they plowed into intergalactic space, and could therefore expand faster and farther in a shorter amount of time.

This of course just begs the question: Why is the local IGM so rarefied on so large a scale? Originally, the group thought that it was simply a naturally under-dense region of space, similar to a void — an underdensity dozens of megaparsecs across that formed shortly after the Big Bang. However, after additional VLA and GMRT measurements (Machalski et al. 2011), they considered an alternative possibility: that the jets were the result of more than one round of AGN activity.

Double, double, radio bubbles

The team suggested classifying J1420–0545 as a double-double radio galaxy (DDRG). DDRGs exhibit two pairs of lobes that are aligned to within a few degrees, indicating that the central AGN underwent a period of activity, shut down, and then restarted. The key piece of information from the old VLA and GMRT data that suggested that J1420–0545 might be an extreme DDRG was the shape of its jets. The narrow jets are characteristic of double-double radio galaxies undergoing their second period of activity.

If the DDRG hypothesis is true, there should be a second faint outer radio cocoon surrounding the structure. After the first period of AGN activity, once the jets ceased, the cocoon should have quickly cooled through energy losses by synchrotron radiation and inverse-Compton scattering; with a suitable choice of parameters, it would be quite possible for it to be below the sensitivity of the VLA and GMRT. However, the team is hopeful that higher-sensitivity measurements in the future might be able to discover it.

In an interesting twist, it was suggested around the same time that 3C 236 is also a DDRG — albeit one in the very early stages of its second period of AGN activity (Tremblay et al. 2010 The Astrophysical Journal). A group observed four bright “knots” near its core that were visible in the far ultraviolet. They appear to be associated with the AGN’s dust disk, and are about ten million years old.

Fig. 4, Tremblay et al. The star-forming knots in the core of 3C 236. The nucleus itself, hiding a supermassive black hole, is surrounded by dust lanes

3C 236’s two large radio lobes appear to be relic, and it has a smaller (~2 kpc) compact structure that seems to be much more recent. This is the key bit of evidence suggesting that it, too, might be a DDRG: The compact radio structure appears to be the same age as the knots, meaning that whatever event caused one likely caused the other. For instance, if a new reservoir of gas became available, it could fuel both AGN activity and a new round of star formation. If this is true, and the compact source ends up resulting in jets, it’s possible that 3C 236 could end up the size of J1420–0545 — or larger.

I’ll end this post by discussing the question I posed in the title: Does J1420–0545 deserve to be called the largest known galaxy? We don’t know quite how large its stellar halo is, but it’s assuredly much smaller than the giant radio cocoon that surrounds it. At the same time, the cocoon represents a very distinct boundary between the galaxy and the intergalactic medium, and the shocked plasma inside it should behave quite differently from plasma in the IGM. Ironically, unlike normal elliptical galaxies that have diffuse halos, we can place a finger on where this giant ends and where intergalactic space begins.

One day, perhaps, we’ll find a giant radio galaxy even larger than J1420–0545, and the question will be moot. For now, though, I leave the question open— and I’ll wait for more VLA data. Clinching evidence of an outer cocoon could be around the corner. All we have to do is wait and see.

See the full article here .

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About Medium

Medium is an online publishing platform developed by Evan Williams, and launched in August 2012. It is owned by A Medium Corporation. The platform is an example of social journalism, having a hybrid collection of amateur and professional people and publications, or exclusive blogs or publishers on Medium, and is regularly regarded as a blog host.

Williams developed Medium as a way to publish writings and documents longer than Twitter’s 140-character (now 280-character) maximum.

From Brookhaven National Lab: “Radio Telescope Gets Upgrade at Brookhaven Lab”

From Brookhaven National Lab

February 13, 2019
Stephanie Kossman
skossman@bnl.gov

Scientists at Brookhaven Lab are using a prototype radio telescope to look deep into the universe and gain a better understanding of its accelerated expansion and the nature of dark energy.

Three new dishes were added to the telescope, which will prepare scientists for a larger project potentially on the horizon.

A radio telescope at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory has received a significant upgrade, advancing from one dish to four. The upgrades are part of the Laboratory’s ongoing effort to test the merits of a radio telescope for a potential future project between national labs and DOE-sponsored universities. The scientists’ ultimate goal is to look deep into the universe and gain a better understanding of periods of accelerated expansion and the nature of dark energy.

“In the study of the universe, the first goal is to survey large-scale structures over as much cosmic volume and time as possible,” said Anže Slosar, a physicist at Brookhaven Lab. “Now, we are experimenting with a new technique that relies on radio waves, and it could enable us to observe the universe much more efficiently.”
Mapping the universe with radio waves

Cosmologists primarily use optical telescopes—telescopes that observe space through visible light—to study galaxies and their distributions in space and time. Optical telescopes can detect the faint light emitted from galaxies that are so far away from Earth that their light has taken 11 billion years to reach us. But radio telescopes, which detect radio waves produced at a particular wavelength by hydrogen gas in distant galaxies—a research field called 21 centimeter cosmology—can enable scientists to “see” a different picture of the universe.

“Compared to optical telescopes, radio telescopes could also see further out—further back in time and further distances in the universe,” said Paul Stankus, a physicist at Oak Ridge National Laboratory and a collaborator on Brookhaven’s radio telescope.

Radio telescopes have a similar design to optical telescopes; they both include a camera and a focusing element that reflects light to generate an image of the universe. But instead of having a glass mirror that reflects visible light, radio telescopes can use a metal reflector dish that costs about 100 times less than a glass mirror of the same size, making them a much more cost-effective way to observe the universe.

Traditional radio telescopes for astronomical studies use large radio dishes, or a collection of widely separated dishes, to obtain high resolution images of individual celestial objects.

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

For Brookhaven’s cosmological applications, however, a different kind of radio telescope is needed: one that can observe large patches of the sky with modest resolution, and can detect changes in the intensity of incoming radio waves with extreme precision.

“For our purposes, seeing a very blurry picture of the universe is okay because we are not interested in observing individual objects. We want to measure big swaths of the universe,” said Slosar. “Using radio emissions to measure structures in deep space over very large volumes will help us gain a better understanding of the fundamental properties of our universe.”

Detecting interference

The current radio telescope on site at Brookhaven Lab is a small prototype, and it was first installed in 2017. Initially, the prototype served as a testbed for scientists to manage radio frequency interference generated by the nearby weather radar, broadcast TV, and cell phone towers. Understanding how to mitigate these large sources of interference will prepare the group for managing smaller sources of interference if a larger telescope is constructed on a more remote site.

During the first months of observations, the scientists detected this expected interference, but they also found something more unusual.

“We saw mysterious signals that seemed to be coming from an astronomical radio source,” said Paul O’Connor, a senior scientist in Brookhaven’s instrumentation division. “They reappeared at the right time interval, but not quite at the right angle and position of the sky, and without the expected frequency spectrum.”

After characterizing the signals and calibrating the telescope, they determined that the signals were coming from navigational satellites whose orbits happened to pass directly over the dish.

“Our radio telescope can see dozens of navigational satellites from around the world, but that’s not really an achievement,” Slosar said. “These satellites are so powerful that our phones can see them. The achievement was detecting these satellites beyond their allocated frequency band, where they are about 1,000 times less powerful.” This low power signal is still capable of causing problems for radio telescopes, so identifying the signal and learning how to work with it is a crucial step towards preparing for a larger radio telescope project.

From one dish to four

Successful measurements in the first year of observations and additional funding through Brookhaven’s Laboratory Directed Research and Development program have enabled the researchers to enhance the prototype telescope and collect more advanced data. Most significantly, the telescope has been upgraded from one dish to four.

“Having four dishes enables us to use a technique called interferometry, where you can combine signals from two dishes,” Slosar said. “Now, the four dishes will act like one very large dish. This is a standard technique in radio astronomy, but it is important that we test its functionality in our prototype in order to prepare for a larger experiment in the future.”

O’Connor added, “the dish construction was largely student-led. We had seven students working on the telescope last summer and we have more coming this year.”

In the years to come, the prototype telescope will continue to serve a testbed for interferometry and other research techniques that the scientists hope to use in a larger experiment. Other plans include using drones that carry radio sources to calibrate the telescope.

“We’ve always had the plan to go from one dish to four, and now that we’ve done that, we consider the design of this testbed instrument complete,” Slosar said. “When we’re ready for further upgrades, those will be planned for a bigger experiment. For now, this prototype will be a long-term testbed while we transition to the research and development phase for a larger project.”

So far, the prototype has already proven itself as promising new way to “see” the universe.

“We’ve compared our data to existing data that radio telescopes have produced of the Milky Way, and it matches perfectly,” said Chris Sheehy, a physicist at Brookhaven. “The difference is that the ‘bandwidth’ of our prototype is increased by a factor of 100. So, while other experiments have mapped the Milky Way at a very narrow frequency band, we see that range as a narrow stripe in our data, and we can also see a factor of 100 more.”

Regarding a larger radio telescope project, the researchers are continuing to collaborate with other national labs and DOE-supported universities to build a case; they’re designing a concept that they hope to see come to life in the next 10 years. Successful observations from Brookhaven’s prototype would be one of many important examples to support a case for such an experiment on a larger and international scale.

This research was supported by Brookhaven’s Laboratory Directed Research and Development funding.

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BNL NSLS-II

BNL NSLS II

BNL RHIC Campus

BNL/RHIC Star Detector

BNL RHIC PHENIX

One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world. Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.

From ALMA: “Liberal Sprinkling of Salt Discovered around a Young Star”

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

From ALMA

7 February, 2019

Valeria Foncea
Education and Public Outreach Officer
Joint ALMA Observatory Santiago – Chile
Phone: +56 2 2467 6258
Cell phone: +56 9 7587 1963
Email: valeria.foncea@alma.cl

Charles E. Blue
Public Information Officer
National Radio Astronomy Observatory Charlottesville, Virginia – USA
Phone: +1 434 296 0314
Cell phone: +1 202 236 6324
Email: cblue@nrao.edu

Calum Turner
ESO Assistant Public Information Officer
Garching bei München, Germany
Phone: +49 89 3200 6670
Email: calum.turner@eso.org

Masaaki Hiramatsu
Education and Public Outreach Officer, NAOJ Chile
Observatory
, Tokyo – Japan
Phone: +81 422 34 3630
Email: hiramatsu.masaaki@nao.ac.jp

Artist impression of Orion Source I, a young, massive star about 1,500 light-years away. New ALMA observations detected a ring of salt — sodium chloride, ordinary table salt — surrounding the star. This is the first detection of salts of any kind associated with a young star. The blue region (about 1/3 the way out from the center of the disk) represents the region where ALMA detected the millimeter-wavelength “glow” from the salts. Credit: NRAO/AUI/NSF; S. Dagnello

ALMA image of the salty disk surrounding the young, massive star Orion Source I (blue ring). It is shown in relation to the Orion Molecular Cloud 1, a region of explosive starbirth. The background near infrared image was taken with the Gemini Observatory. Credit: ALMA (NRAO/ESO/NAOJ); NRAO/AUI/NSF; Gemini Observatory/AURA

Gemini South telescope, Cerro Tololo Inter-American Observatory (CTIO) campus near La Serena, Chile, at an altitude of 7200 feet

A team of astronomers and chemists using the Atacama Large Millimeter/submillimeter Array (ALMA) has detected the chemical fingerprints of sodium chloride (NaCl) and other similar salty compounds emanating from the dusty disk surrounding Orion Source I, a massive, young star in a dusty cloud behind the Orion Nebula.

“It’s amazing we’re seeing these molecules at all,” said Adam Ginsburg, a Jansky Fellow of the National Radio Astronomy Observatory (NRAO) in Socorro, New Mexico, and lead author of a paper accepted for publication in The Astrophysical Journal. “Since we’ve only ever seen these compounds in the sloughed-off outer layers of dying stars, we don’t fully know what our new discovery means. The nature of the detection, however, shows that the environment around this star is very unusual.”

To detect molecules in space, astronomers use radio telescopes to search for their chemical signatures – telltale spikes in the spread-out spectra of radio and millimeter-wavelength light. Atoms and molecules emit these signals in several ways, depending on the temperature of their environments.

The new ALMA observations contain a bristling array of spectral signatures – or transitions, as astronomers refer to them – of the same molecules. To create such strong and varied molecular fingerprints, the temperature differences where the molecules reside must be extreme, ranging anywhere from 100 kelvin to 4,000 kelvin (about -175 Celsius to 3700 Celsius). An in-depth study of these spectral spikes could provide insights about how the star is heating the disk, which would also be a useful measure of the luminosity of the star.

“When we look at the information ALMA has provided, we see about 60 different transitions – or unique fingerprints – of molecules like sodium chloride and potassium chloride coming from the disk. That is both shocking and exciting,” said Brett McGuire, a chemist at the NRAO in Charlottesville, Virginia, and co-author on the paper.

The researchers speculate that these salts come from dust grains that collided and spilled their contents into the surrounding disk. Their observations confirm that the salty regions trace the location of the circumstellar disk.

“Usually when we study protostars in this manner, the signals from the disk and the outflow from the star get muddled, making it difficult to distinguish one from the other,” said Ginsburg. “Since we can now isolate just the disk, we can learn how it is moving and how much mass it contains. It also may tell us new things about the star.”

The detection of salts around a young star is also of interest to astronomers and astrochemists because some of constituent atoms of salts are metals – sodium and potassium. This suggests there may be other metal-containing molecules in this environment. If so, it may be possible to use similar observations to measure the amount of metals in star-forming regions. “This type of study is not available to us at all presently. Free-floating metallic compounds are generally invisible to radio astronomy,” noted McGuire.

The salty signatures were found about 30 to 60 astronomical units (AU, or the average distance between the Earth and the Sun) from the host stars. Based on their observations, the astronomers infer that there may be as much as one sextillion (a one with 21 zeros after it) kilograms of salt in this region, which is roughly equivalent to the entire mass of Earth’s oceans.

“Our next step in this research is to look for salts and metallic molecules in other regions. This will help us understand if these chemical fingerprints are a powerful tool to study a wide range of protoplanetary disks, or if this detection is unique to this source,” said Ginsburg. “In looking to the future, the planned Next Generation VLA would have the right mix of sensitivity and wavelength coverage to study these molecules and perhaps use them as tracers for planet-forming disks.”

Orion Source I formed in the Orion Molecular Cloud I, a region of explosive starbirth previously observed with ALMA. “This star was ejected from its parent cloud with a speed of about 10 kilometers per second around 550 years ago,”1 said John Bally, an astronomer at the University of Colorado and co-author on the paper. “It is possible that solid grains of salt were vaporized by shock waves as the star and its disk were abruptly accelerated by a close encounter or collision with another star. It remains to be seen if salt vapor is present in all disks surrounding massive protostars, or if such vapor traces violent events like the one we observed with ALMA.”

1. Light from this object took about 1,500 years to reach Earth. Astronomers are seeing it as if looking through that window of time, which reveals how it looked 550 years after it was ejected from its stellar nursery.

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

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