From ALMA: “Two Cosmic Peacocks Show Violent History of the Magellanic Clouds”

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

From ALMA

14 November, 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

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

Bárbara Ferreira
ESO Public Information Officer
Garching bei München, Germany
Phone: +49 89 3200 6670
Email: pio@eso.org

Iris Nijman
Public Information Officer
National Radio Astronomy Observatory Charlottesville, Virginia – USA
Cell phone: +1 (434) 249 3423
Email: alma-pr@nrao.edu

1
ALMA images of two molecular clouds N159E-Papillon Nebula (left) and N159W South (right). Red and green show the distribution of molecular gas in different velocities seen in the emission from 13CO. Blue region in N159E-Papillon Nebula shows the ionized hydrogen gas observed with the Hubble Space Telescope. Blue part in N159W South shows the emission from dust particles obtained with ALMA. Credit: ALMA (ESO/NAOJ/NRAO)/Fukui et al./Tokuda et al./NASA-ESA Hubble Space Telescope

NASA/ESA Hubble Telescope

3
Artist’s impression of the formation process of peacock-shaped clouds. After collision of two clouds (left), complicated filamentary structures with a pivot in the bottom are formed in the boundary region (center), and a massive star is formed in the dense part with ionized region shown in blue (right). Credit: NAOJ

Two peacock-shaped gas clouds were revealed in the Large Magellanic Cloud (LMC) by observations with the Atacama Large Millimeter/submillimeter Array (ALMA). A team of astronomers found several massive baby stars in the complex filamentary clouds, which agrees well with computer simulations of giant collisions of gas clouds. The researchers interpret this to mean that the filaments and young stars are telltale evidence of violent interactions between the LMC and the Small Magellanic Cloud (SMC) 200 million years ago.

Large Magellanic Cloud. Adrian Pingstone December 2003

smc

Small Magellanic Cloud. NASA/ESA Hubble and ESO/Digitized Sky Survey 2

Astronomers know that stars are formed in collapsing clouds in space. However, the formation processes of giant stars, 10 times or more massive than the Sun, are not well understood because it is difficult to pack such a large amount of material into a small region. Some researchers suggest that interactions between galaxies provide a perfect environment for massive star formation. Due to the colossal gravity, clouds in the galaxies are stirred, stretched, and often collide with each other. A huge amount of gas is compressed in an unusually small area, which could form the seeds of massive stars.

A research team used ALMA to study the structure of dense gas in N159, a bustling star formation region in the LMC. Thanks to ALMA’s high resolution, the team obtained a very detailed map of the clouds in two sub-regions, N159E-Papillon Nebula and N159W South.

Interestingly, the cloud structures in the two regions look very similar: fan-shaped filaments of gas extending to the north with the pivots in the southernmost points. The ALMA observations also found several massive baby stars in the filaments in the two regions.

“It is unnatural that in two regions separated by 150 light-years, clouds with such similar shapes were formed and that the ages of the baby stars are similar in two regions separated 150 light years,” says Kazuki Tokuda, a researcher at Osaka Prefecture University and the National Astronomical Observatory of Japan. “There must be a common cause of these features. Interaction between the LMC and SMC is a good candidate.”

Magellanic Bridge ESA Gaia satellite. Image credit V. Belokurov D. Erkal A. Mellinger.

In 2017, Yasuo Fukui, a professor at Nagoya University and his team revealed the motion of hydrogen gas in the LMC and found that a gaseous component right next to N159 has a different velocity than the rest of the clouds. They suggested a hypothesis that the starburst is caused by a massive flow of gas from the SMC to the LMC, and that this flow originated from a close encounter between the two galaxies 200 million years ago.

The pair of the peacock-shaped clouds in the two regions revealed by ALMA fits nicely with this hypothesis. Computer simulations show that many filamentary structures are formed in a short time scale after a collision of two clouds, which also backs this idea.

“For the first time, we uncovered the link between massive star formation and galaxy interactions in very sharp detail,” says Fukui, the lead author of one of the research papers. “This is an important step in understanding the formation process of massive star clusters in which galaxy interactions have a big impact.”

Additional Information

This research was presented in the following two papers on 14 November 2019 in The Astrophysical Journal.

Fukui et al. “An ALMA view of molecular filaments in the Large Magellanic Cloud I: The formation of high-mass stars and pillars in the N159E-Papillon Nebula triggered by a cloud-cloud collision”
Tokuda et al. “An ALMA view of molecular filaments in the Large Magellanic Cloud II: An early stage of high-mass star formation embedded at colliding clouds in N159W-South”

Research team members are:

Yasuo Fukui (Nagoya University), Kazuki Tokuda (Osaka Prefecture University/National Astronomical Observatory of Japan), Kazuya Saigo (National Astronomical Observatory of Japan), Ryohei Harada (Osaka Prefecture University), Kengo Tachihara (Nagoya University), Kisetsu Tsuge (Nagoya University), Tsuyoshi Inoue (Nagoya University), Kazufumi Torii (National Astronomical Observatory of Japan), Atsushi Nishimura (Nagoya University), Sarolta Zahorecz (Osaka Prefecture University/National Astronomical Observatory of Japan), Omnarayani Nayak (Space Telescope Science Institute), Margaret Meixner (Johns Hopkins University/Space Telescope Science Institute), Tetsuhiro Minamidani (National Astronomical Observatory of Japan), Akiko Kawamura (National Astronomical Observatory of Japan), Norikazu Mizuno (National Astronomical Observatory of Japan/Joint ALMA Observatory), Remy Indebetouw (University of Virginia/National Radio Astronomy Observatory), Marta Sewiło (NASA Goddard Space Flight Center/University of Maryland), Suzanne Madden (Université Paris-Saclay), Maud Galametz(Université Paris-Saclay), Vianney Lebouteiller (Université Paris-Saclay), C.-H. Rosie Chen (Max Planck Institute for Radio Astronomy), and Toshikazu Onishi (Osaka Prefecture University)

This research was supported by JSPS KAKENHI (No. 22244014, 23403001, 26247026, 18K13582, 18K13580,18H05440), NAOJ ALMA Scientific Research Grant (No. 2016-03B), and NASA (No.80GSFC17M0002).

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.

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From ALMA: “ALMA Witness Planet Formation in Action”

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

From ALMA

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

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

Bárbara Ferreira
ESO Public Information Officer
Garching bei München, Germany
Phone: +49 89 3200 6670
Email: pio@eso.org

Iris Nijman
Public Information Officer
National Radio Astronomy Observatory Charlottesville, Virginia – USA
Cell phone: +1 (434) 249 3423
Email: alma-pr@nrao.edu

1
Artist’s impression of gas flowing like a waterfall into a protoplanetary disk gap, which is most likely caused by an infant planet. Credit: NRAO/AUI/NSF, S. Dagnello.

2
Scientists measured the motion of gas (arrows) in a protoplanetary disk in three directions: rotating around the star, towards or away from the star, and up- or downwards in the disk. The inset shows a close-up of where a planet in orbit around the star pushes the gas and dust aside, opening a gap. Credit: NRAO/AUI/NSF, B. Saxton.

3
A computer simulation showed that the patterns of gas flows are unique and are most likely caused by planets in three locations in the disk. Planets in orbit around the star push the gas and dust aside, opening gaps. The gas above the gaps collapses into it like a waterfall, causing a rotational flow of gas in the disk. Credit: ALMA (ESO/NAOJ/NRAO), J. Bae; NRAO/AUI/NSF, S. Dagnello.

For the first time, astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have witnessed 3D motions of gas in a planet-forming disk. At three locations in the disk around a young star called HD 163296, gas is flowing like a waterfall into gaps that are most likely caused by planets in formation. These gas flows have long been predicted and would directly influence the chemical composition of planets atmospheres. This research appears in the latest issue of the journal Nature.

The birthplaces of planets are disks made out of gas and dust. Astronomers study these so-called protoplanetary disks to understand the processes of planet formation. Beautiful images of disks made with ALMA show distinct gaps and ring features in the dust, which may be caused by infant planets.

To get more certainty that planets cause these gaps, and to get a complete view of planetary formation, scientists study the gas in the disks in addition to dust. Ninety-nine percent of a protoplanetary disk’s mass is gas, of which carbon monoxide (CO) is the brightest component, and ALMA can observe it.

Last year, two teams of astronomers demonstrated a new planet-hunting technique using this gas. They measured the velocity of CO gas rotating in the disk around the young star HD 163296. Localized disturbances in the movements of the gas revealed three planet-like patterns in the disk.

In this new study, lead author Richard Teague from the University of Michigan and his team used new high-resolution ALMA data from the Disk Substructures at High Angular Resolution Project (DSHARP) to study the gas’s velocity in more detail. “With the high-fidelity data from this program, we were able to measure the gas’s velocity in three directions instead of just one,” said Teague. “For the first time, we measured the motion of the gas in every possible direction. Rotating around, moving towards or away from the star, and up or downwards in the disk.”

Teague and his colleagues saw the gas moving from the upper layers towards the middle of the disk at three different locations. “What most likely happens is that a planet in orbit around the star pushes the gas and dust aside, opening a gap,” Teague explained. “The gas above the gap then collapses into it like a waterfall, causing a rotational flow of gas in the disk.”

This is the best evidence to date that there are indeed planets forming around HD 163296. But astronomers cannot say with one hundred percent certainty that planets cause the gas flows. For example, the star’s magnetic field could also cause disturbances in the gas. “Right now, only direct observation of the planets could rule out the other options. But, the patterns of these gas flows are unique, and very likely, only planets can cause them,” said coauthor Jaehan Bae of the Carnegie Institution for Science, who tested this theory with a computer simulation of the disk.

The location of the three predicted planets in this study correspond to the results from last year. Their positions probably are at 87, 140, and 237 AU (An astronomical unit – AU – is the average distance from the Earth to the Sun). The closest planet to HD 163296 is calculated to be half the mass of Jupiter, the middle planet is Jupiter-mass, and the farthest planet is twice as massive as Jupiter.

Gas flows from the surface towards the midplane of the protoplanetary disk have been predicted since the late nineties. But this is the first time that astronomers observed them. Besides being useful to detect infant planets, these flows can also shape our understanding of how gas giant planets obtain their atmospheres.

“Planets form in the middle layer of the disk, the so-called midplane. This is a cold place, shielded from radiation from the star,” Teague explained. “We think that the gaps caused by planets bring in warmer gas from the more chemically active outer layers of the disk and that this gas will form the atmosphere of the planet.”

Teague and his team did not expect that they would be able to see this phenomenon. “The disk around HD 163296 is the brightest and biggest disk we can see with ALMA,” said Teague. “But it was a big surprise to see these gas flows so clearly. The disks appear to be much more dynamic than we thought.”

“This gives us a much more complete picture of planet formation than we ever dreamed,” said coauthor Ted Bergin of the University of Michigan. “By characterizing these flows, we can determine how planets like Jupiter are born and characterize their chemical composition at birth. We might be able to use this to trace the birth location of these planets, as they can move during formation.”

Additional information

This research is presented in a paper by R. Teague et al. in Nature.

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.

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From ALMA: “ALMA Observes Counter-intuitive Flows Around Black Hole”

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

From ALMA

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

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

Bárbara Ferreira
ESO Public Information Officer
Garching bei München, Germany
Phone: +49 89 3200 6670
Email: pio@eso.org

Iris Nijman
Public Information Officer
National Radio Astronomy Observatory Charlottesville, Virginia – USA
Cell phone: +1 (434) 249 3423
Email: alma-pr@nrao.edu

1
Artist impression of the heart of galaxy NGC 1068, which harbors an actively feeding supermassive black hole, hidden within a thick doughnut-shaped cloud of dust and gas. ALMA discovered two counter-rotating flows of gas around the black hole. The colors in this image represent the motion of the gas: blue is material moving toward us, red is moving away. Credit: NRAO/AUI/NSF, S. Dagnello.

2
ALMA image showing two disks of gas moving in opposite directions around the black hole in galaxy NGC 1068. The colors in this image represent the motion of the gas: blue is material moving toward us, red is moving away. The white triangles are added to show the accelerated gas that is expelled from the inner disk – forming a thick, obscuring cloud around the black hole. Credit: ALMA (ESO/NAOJ/NRAO), V. Impellizzeri; NRAO/AUI/NSF, S. Dagnello.

At the center of a galaxy called NGC 1068, a supermassive black hole hides within a thick doughnut-shaped cloud of dust and gas. When astronomers used the Atacama Large Millimeter/submillimeter Array (ALMA) to study this cloud in more detail, they made an unexpected discovery that could explain why supermassive black holes grew so rapidly in the early Universe.

“Thanks to the spectacular resolution of ALMA, we measured the movement of gas in the inner orbits around the black hole,” explains Violette Impellizzeri of the National Radio Astronomy Observatory (NRAO), working at ALMA in Chile and lead author on a paper published in The Astrophysical Journal Letters. “Surprisingly, we found two disks of gas rotating in opposite directions.”

Supermassive black holes already existed when the Universe was young, just a billion years after the Big Bang. But how these extreme objects, whose masses are up to billions of times the mass of the Sun, had time to grow so fast, is an outstanding question among astronomers. This new ALMA discovery could provide a clue. “Counter-rotating gas streams are unstable, which means that clouds fall into the black hole faster than they do in a disk with a single rotation direction,” said Impellizzeri. “This could be a way in which a black hole can grow rapidly.”

NGC 1068 (also known as Messier 77) is a spiral galaxy approximately 47 million light-years from Earth in the direction of the constellation Cetus. At its center is an active galactic nucleus, a supermassive black hole that is actively feeding itself from a thin, rotating disk of gas and dust, also known as an accretion disk.

Previous ALMA observations revealed that the black hole is gulping down material and spewing out gas at incredibly high speeds. This gas that gets expelled from the accretion disk likely contributes to hiding the region around the black hole from optical telescopes.

Impellizzeri and her team used ALMA’s superior zoom lens ability to observe the molecular gas around the black hole. Unexpectedly, they found two counter-rotating disks of gas. The inner disk spans 2-4 light-years and follows the rotation of the galaxy, whereas the outer disk (also known as the torus) spans 4-22 light-years and is rotating the opposite way.

“We did not expect to see this, because gas falling into a black hole would normally spin around it in only one direction,” said Impellizzeri. “Something must have disturbed the flow because it is impossible for a part of the disk to start rotating backward all on its own.”

Counter-rotation is not an unusual phenomenon in space. “We see it in galaxies, usually thousands of light-years away from their galactic centers,” explained co-author Jack Gallimore from Bucknell University in Lewisburg, Pennsylvania. “The counter-rotation always results from the collision or interaction between two galaxies. What makes this result remarkable is that we see it on a much smaller scale, tens of light-years instead of thousands from the central black hole.”

The astronomers think that the backward flow in NGC 1068 might be caused by gas clouds that fell out of the host galaxy, or by a small passing galaxy on a counter-rotating orbit captured in the disk.

At the moment, the outer disk appears to be in a stable orbit around the inner disk. “That will change when the outer disk begins to fall onto the inner disk, which may happen after a few orbits or a few hundred thousand years. The rotating streams of gas will collide and become unstable, and the disks will likely collapse in a luminous event as the molecular gas falls into the black hole. Unfortunately, we will not be there to witness the fireworks,” said Gallimore.

Additional Information

The research team was composed by Violette Impellizzeri1,2, Jack F. Gallimore3, Stefi A. Baum4, Moshe Elitzur5, Richard Davies6, Dieter Lutz6, Roberto Maiolino7, Alessandro Marconi8,9, Robert Nikutta10, Christopher P. O’Dea4, and Eleonora Sani11.

1 Joint ALMA Observatory, Alonso de Cordova 3107, Vitacura, Santiago, Chile

2 National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903, USA

3 Department of Physics and Astronomy, Bucknell University, Lewisburg, PA 17837, USA

4 University of Manitoba, Department of Physics and Astronomy, Winnipeg, MB R3T 2N2, Canada

5 Astronomy Department, University of California, Berkeley, CA 94720, USA

6 Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse 1, D-85748 Garching, Germany

7 Kavli Institute for Cosmology, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK

8 Dipartimento di Fisica e Astronomia, Universit’a di Firenze, via G. Sansone 1, I-50019, Sesto Fiorentino (Firenze), Italy

9 INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50135, Firenze, Italy

10 National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719, USA

11 European Southern Observatory, Alonso de Cordova 3107, Vitacura, Santiago, Chile

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.

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From ALMA: “Feeding a Baby Star Through a Whirlpool in Space”

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

From ALMA

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

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

Mariya Lyubenova
ESO Outreach Astronomer
Garching bei München, Germany
Phone: +49 89 32 00 61 88
Email: mlyubeno@eso.org

Iris Nijman
Public Information Officer
National Radio Astronomy Observatory Charlottesville, Virginia – USA
+1 (434) 249 3423
alma-pr@nrao.edu

1

Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) detected a pair of spiral arms in an accretion disk around a baby star. Interestingly, these spiral density enhancements make the disk appear like a “space whirlpool.” The finding supports current theories of accretion disk feeding process, and potentially brings critical insights into the processes of grain growth and settling that are important to planet formation. These results appear in an article in Nature Astronomy led by Chin-Fei Lee at Academia Sinica Institute of Astronomy and Astrophysics (ASIAA, Taiwan).

“Thanks to the resolving power of ALMA, we finally detected a pair of spirals in a young accretion disk around a baby star. These spirals, long predicted in theory, play a crucial role in the transport of angular momentum. Which allows disk material to swirl towards the baby star”, says Lee with excitement. “Our detection of the spirals is an important milestone in understanding the feeding process of baby stars.”

Spirals detected in protoplanetary disks around somewhat older stars seem to be produced by interaction with unseen baby planets. Unlike those, the spirals here are induced by accretion of material from the surrounding molecular cloud onto the disk.

The protostar with its disk lies at the center of HH 111, a pair of supersonic jets emerging from a molecular cloud core located 1300 lightyears away in the constellation Orion. The protostar is about half a million years old, just one ten-thousandth the age of our Sun, and has a mass 50% greater than our Sun. A portion of the flow through the disk onto the budding star is diverted to form the spectacular jets. Previous observations with a resolution of 120 AU (An astronomical unit – AU – is the average distance from the Earth to the Sun) detected the accretion disk orbiting the protostar out to a radius of 160 AU. The new observations with ALMA have a resolution of 16 AU, almost eight times better. With this outstanding capability, astronomers were able to resolve the disk spatially. They detected a pair of spiral arms by the glow of thermal emission from dust particles concentrated there (Figure 1).

The team’s observations open up the exciting possibility of detecting spiral structures in the accretion disks around protostars through high-resolution and high-sensitivity imaging with ALMA, which allows studying accretion disk feeding processes in depth. Such observations also provide insight into accretion disks around other kinds of astrophysical objects, including the supermassive black holes found at the center of active galaxies.

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(Top) Optical image of the jet in the HH 111 protostellar system taken by the Hubble Space Telescope (Reipurth et al. 1999). (Bottom left) Accretion disk detected with ALMA in dust continuum emission at 850 micron. (Bottom middle) The disk turned (de-projected) to be face-on, showing a pair of faint spirals. (Bottom right) Annularly averaged continuum emission is subtracted to highlight the faint spirals in the disk. Credit: ALMA (ESO/NAOJ/NRAO)/Lee et al.

The team is composed of Chin-Fei Lee (ASIAA, Taiwan; National Taiwan University, Taiwan), Zhi-Yun Li (University of Virginia, USA), and Neal J. Turner (JPL/Caltech, USA).

See the full article here .

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

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.

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#feeding-a-baby-star-through-a-whirlpool-in-space, #alma, #astronomy, #astrophysics, #basic-research, #cosmology, #millimetersubmillimeter-astronomy, #radio-astronomy

From ALMA: “Rarest form of CO Provides Hint to the Birth of Planets around Young Star”

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

From ALMA

Astronomers have discovered the rarest stable carbon monoxide isotope molecule, 13C17O, in the dust and gas disk around a young star using ALMA for the first time. The observations indicate that the disk is more massive than previous estimates, and they may provide an important key to solve mysteries about the planet formation processes in disks.

1
Images of 13C17O line emission (green), 12C16O line emission (blue), and dust continuum emission (red and blue) Credit; ALMA (ESO/NAOJ/NRAO), University of Leeds

The young star, named HD 163296, is located 330 light-years away in the constellation Sagittarius. It is surrounded by a disk of dust and gas – a so-called protoplanetary disk, in which young planets are forming. This disk has multiple ring and gap patterns which are thought to be sub-structures induced by new-born large planets. (https://alma-telescope.jp/en/news/dsharp-201812)

Using the Atacama Large Millimeter/submillimeter Array (ALMA) in the Atacama Desert, Chile, researchers detected an extremely faint signal showing the existence of 13C17O, a rare carbon monoxide isotopologue, that is to say a molecule containing one or more isotopes.

The detection has allowed scientists to measure the mass of the gas in the disk more accurately than before. The results show that the disk is much heavier – or more ‘massive’ – than previously thought.

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An artist’s impression of planets forming in the ring of gas and dust surrounding a star. Credit; ESO/ L. Calçada

Alice Booth, a PhD student in the School of Physics and Astronomy, University of Leeds who led the study [The Astrophysical Journal Letters], said: “Our new observations showed there was between two and six times more mass hiding in the disk than previous observations could measure. This is an important finding in terms of the birth of planetary systems in disks – if they contain more gas, then they have more building material to form more massive planets.”

The research team members are:
Alice S. Booth (University of Leeds), Catherine Walsh (University of Leeds), John D. Ilee (University of Leeds), Shota Notsu (Leiden University/Kyoto University), Chunhua Qi (Harvard-Smithsonian Center for Astrophysics), Hideko Nomura (National Astronomical Observatory of Japan/Tokyo Institute of Technology), Eiji Akiyama (Hokkaido University)

This group’s conclusions are well timed. Recent observations of protoplanetary disks have perplexed astronomers because the disks did not seem to contain enough gas and dust to create the planets observed.

Dr. John Ilee, a researcher at University of Leeds who was also involved in the study, added: “The disk-exoplanet mass discrepancy raises serious questions about how and when planets are formed. However, if other disks are hiding similar amounts of mass as HD 163296, then we may just have underestimated their masses until now.”

Disk gas masses are usually estimated by observing common forms of carbon monoxide (CO). This molecule is the most useful to determine disk gas mass, since it is abundant and is much easier to observe in cold disks than hydrogen molecules. However the fact that CO is abundant can also become a problem. If the disks are sufficiently dense, however, then the outermost CO molecules start to block part of the emissions from CO molecules deeper within the disk – and that could result in scientists underestimating the total mass of the gas.

In this study, the scientists targeted the much rarer 13C17O molecule. Because it is rarer, there is less self-blocking, so that the observers could peer deeper inside the disk and find previously hidden gas.

The scientists expect that using ALMA, they can observe this rare form of CO in many other disks. Dr. Shota Notsu, a JSPS Overseas Research Fellow in Leiden Observatory, Leiden University who was also involved in this study, said: “Measuring the accurate disk masses is key to understand processes of planet formation. Future studies using the rarest forms of CO will enable us to measure the missing mass in many more protoplanetary disks and determine their planet-forming potential.”

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.

NRAO Small
ESO 50 Large

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From SKA: “French NenuFAR telescope granted SKA Pathfinder status”

SKA South Africa


From SKA

10.9.19

The SKA Organisation has officially recognised NenuFAR, a French radio telescope, as a Pathfinder Project of the SKA telescope.

NenuFAR Array in France NenuFAR, which stands for New Extension in Nançay Upgrading LOFAR

NenuFAR, which stands for New Extension in Nançay Upgrading LOFAR, is a new low-frequency radio telescope under construction at the Nançay Observatory near Orleans to extend the existing international LOFAR radio telescope, an array of low frequency antennas spread across eight European countries and centred in the Netherlands.

“With this announcement, NenuFAR is recognised as an instrument concept paving the way for the new science to be done with the SKA”, said Gilles Theureau, Director of the Nançay Observatory. “It’s excellent news for the project, as well as for the Nançay Observatory.”

The SKA officially has three precursor telescopes, MeerKAT, ASKAP and MWA. Located at SKA sites in South Africa and Western Australia, these precursors are and will be carrying out scientific studies related to future SKA activities, as well as helping the development and testing of new crucial SKA technologies.

Unlike precursors, pathfinder telescopes and systems are dotted around the globe. They include the famous Arecibo radio telescope in Puerto Rico, which starred in the James Bond movie “Goldeneye”, the LOFAR low frequency array, which is based in Europe, and the JVLA, in North America, which was famously seen in the hit movie “Contact”, amongst others. They are also engaged in SKA-related technology and science studies. A full list is available here.

NenuFAR will not only be an extension of LOFAR but also a stand-alone instrument. As an SKA pathfinder, the feedback from the design, construction and operation of NenuFAR will be used by the SKA Organisation to facilitate the development of the SKA.

“NenuFAR is a promising instrument and the SKA’s low frequency array will certainly benefit from the development and lessons learnt on this project”, said Prof. Philip Diamond, Director General of the SKA Organisation. “We are happy to support the French community’s efforts and look forward to working more closely with our colleagues in France in the near future.”

“The decision by the SKA Organisation to grant NenuFAR the official status of SKA Pathfinder is an important signal for the French community, recognising our expertise in radioastronomy,” added Denis Mourard, Deputy Director for Science of the Institut National des Sciences de l’Univers of CNRS.

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

SKA Hera at SKA South Africa

SKA Pathfinder – LOFAR location at Potsdam via Google Images

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.

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From Symmetry: “A crystal clear place to study the skies”

Symmetry Mag
From Symmetry<

10/09/19
Diana Kwon

1
Artwork by Sandbox Studio, Chicago with Pedro Rivas

In the last few decades, Argentina and Chile have proven themselves prime spots for astronomical observation—a status that has been a boon in many ways for both countries.

In 2000 Ingo Allekotte sat behind a table in Malargüe, a city with a population of fewer than 18,000 in the foothills of the Andes mountains in Argentina, listening to an informal lecture about particles from space. It would have been an unremarkable occasion for Allekotte, a scientist—except that the venue was not a university; it was a restaurant, and the speaker was not a scientist, but a waiter. He just happened to have learned about astrophysics because of where he lives and the people who come to visit.

Attracted by a combination of environmental factors, people like Allekotte had come to Malargüe to install an array of detectors to collect signals from these particles, called cosmic rays.

They weren’t the only ones to choose Latin America as the base for their studies of what lies beyond Earth’s atmosphere. An influx of researchers from around the world has made its mark on science, technology, culture and people in Latin America—including at least one restaurant employee. This is especially true in Malargüe, home to the Pierre Auger cosmic ray observatory, and across Chile, a country with more astronomical observatories than any other.

Pierre Auger Observatory in the western Mendoza Province, Argentina, near the Andes, at an altitude of 1330 m–1620 m, average ~1400 m

A hub for astronomy

Northern Chile’s Atacama Desert could easily be mistaken for the surface of another world. Sparse rainfalls make the Atacama one of the most arid regions on Earth, giving it the parched, barren conditions you would expect to find on Mars.

The Atacama stretches for hundreds of miles between a high coastline in the west and the Andes Mountains in the east. Because of its unique location, the desert has clear skies more than 90% of nights during the year with barely any water vapor in the atmosphere.

“When you put it all together, you get these unique conditions that explain why the Atacama is the best place in the world to put telescopes,” says Ezequiel Treister, an astronomer at the Pontifical Catholic University of Chile.

Currently, the Atacama and the nearby Chilean Andes are home to more than half a dozen scientific astronomical observatories. Once construction of the Large Synoptic Survey Telescope (LSST), the European Extremely Large Telescope (E-ELT) and the Giant Magellan Telescope (GMT) are complete, Chile will be home to around 70% of the total astronomical resources in the world.

LSST telescope, The Vera Rubin Survey 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.

ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile. located at the summit of the mountain at an altitude of 3,060 metres (10,040 ft).

Giant Magellan Telescope, to be at the Carnegie Institution for Science’s Las Campanas Observatory, to be built some 115 km (71 mi) north-northeast of La Serena, Chile, over 2,500 m (8,200 ft) high

Chile’s impeccable night sky has drawn interest from the international scientific community for more than a century. As far back as the 1800s, astronomers from the United States and Europe set out on scientific expeditions to the South American country and helped establish a handful of local astronomical observatories in the region.

In the 1960s, the University of Chile and the US National Science Foundation (NSF) joined forces with the Association for Universities for Research in Astronomy (AURA) to establish the Cerro Tololo Inter-American Observatory (CTIO). This complex of astronomical telescopes and instruments, built in the mountains that skirt the southern edge the Atacama, became Chile’s first large, international observatory. Shortly after, the European Space Observatory (ESO) built the La Silla Observatory, one of several sites it now operates in the country.

Cerro Tololo Inter-American Observatory on Cerro Tololo in the Coquimbo Region of northern Chile Altitude 2,207 m (7,241 ft)

ESO/Cerro LaSilla, 600 km north of Santiago de Chile at an altitude of 2400 metres.

The building boom of observatories that started almost six decades ago is still ongoing today. “The development of astronomy in Chile over the last few decades has been really exponential,” Treister says. “We are very well connected with institutes worldwide, mostly those in the US, Europe and Asia.”

Work conducted at Chilean observatories has contributed to major scientific advances, such as the 1998 discovery that the universe is expanding at an accelerating pace—an insight that led to the study of dark energy—along with the recent first-ever image of a black hole. “It’s really hard for me to think of a single astronomical milestone in the last 20 to 30 years that didn’t involve observatories in Chile,” Treister says.

The trend has contributed to the development in Chile of new astronomy-related university programs and a growth in the number of professional astronomers there. Monica Rubio, an astronomer and the president of the Chilean Astronomical Society (SOCHIAS), recalls that when she enrolled in graduate school in the 1980s, there were no astronomy PhD programs in Chile; she had to go abroad to France to obtain a doctoral degree.

Today, the situation has drastically changed. Over the last few decades, funding provided by both the Chilean government and the international observatories operating in the country has allowed more institutions to offer undergraduate, master’s and PhD programs in astronomy, Rubio says. “We have gone from three universities doing astronomy in 2000 to today where we have 15 universities, more than 200 astronomers and hundreds of students,” she says. “The increase in numbers has been amazing.”

Agreements signed by the observatories to reserve at least 10% of their observing time for academics working at Chilean institutions has helped boost science in the country. “We benefited a lot from the dedicated observing time,” says Ricardo Finger, an engineer at the University of Chile’s Millimeter-wave Laboratory. “Astronomy has developed at a very fast rate, and it’s now one of the most important sciences in Chile.”

Technology transfer

At the Millimeter-wave Laboratory, a multidisciplinary group of astronomers, engineers and technicians works on developing astronomical technologies. This includes building receivers for radio telescopes and generating algorithms for data processing.

In recent years, the laboratory has also been searching for ways to apply its technologies for more widespread use by Chilean industries. One device the team developed uses a phased array technique found in radio telescopes to detect cellular phone signals. The gadget generates a map of electromagnetic radiation in the environment somewhat like a thermal camera generates a heat map of its surroundings.

“The idea was that if you have this camera, you can look into a field and know if there is, for example, a cellphone transmitting, even if it’s hidden,” Finger explains. “That could be useful in different fields, such as search and rescue—especially in Chile, which is a very earthquake-active country.”

The lab also designed a device that can sense temperature and moisture level of soil and transfer that data to a location several kilometers away. The tool is especially useful for the mining industry, Finger explains, which uses a process called “leaching” to extract metals such as copper by pouring a solution of water and acid onto a massive pile of rock. If there is too much water present in the soil, the acid-water mixture can spill over into the surroundings. Too little water, on the other hand, can lead to inefficient extraction.

“A number of companies want to represent this product,” Finger says. “After a few years of trial and error, that’s the first success case we had.”

The team has built a handful of other devices, and it is still on the lookout for additional ways to apply their technology outside of the observatory, Finger says. “There will be new ideas for sure.”

The growth in large observatories—and the massive amounts of data generated from them—has also helped Chile develop advanced tools for big data and astroinformatics.

These technologies will likely get a further boost when LSST, a telescope fitted with the largest digital camera in the world, is complete in the early 2020s. To provide a deep and detailed survey of the universe, the massive telescope being built by NSF will collect some 30 terabytes of data each night.

“The amount of data that LSST will collect is going to be unprecedented,” Rubio says. An advantage of developing technologies to manage this influx of information, she adds, is that “the tools that are required for big data analysis can be easily applied to other disciplines, such as medicine, retail and finance.”

The Chilean government recently launched the “Data Observatory,” an initiative to gather, analyze and store large data sets generated in the country. They plan to use astronomy data as the first test case for this project, which will be carried out in collaboration with Amazon Web Services and Adolfo Ibáñez University.

A unique observatory in Argentina

In 1992, physicists Jim Cronin, a Nobel laureate and professor at the University of Chicago, and Alan Watson, a professor at the University of Leeds in the UK, proposed building a massive observatory to investigate cosmic rays that crash to Earth at unbelievably high energies.

These very-high-energy particles are rare and therefore hard to catch, so the scientists wanted their array of instruments to cover as much ground as possible. Scientists had built cosmic-ray observatories before, but none possessed the collecting power that Cronin and Watson were looking for.

To make this vision a reality, Cronin spearheaded efforts to spread enthusiasm for the project worldwide, which eventually led to an international collaboration. In 1998, after a series of workshops, the group chose a spot just outside of Malargüe in Argentina as the site for their ambitious cosmic-ray observatory, which they named after French cosmic-ray researcher Pierre Auger.

Malargüe was an optimal location for several reasons, says Allekotte, the current project manager at the Pierre Auger Observatory. First of all, the city, which is located in the foothills of the Andes mountains, is surrounded by a very flat area. Being fairly isolated (more than 100 kilometers, or 60 miles, from the next city) and small, it emitted almost no light or air pollution. In addition, previous uranium and oil exploration and extraction projects in the region had left some basic infrastructure, such as roads, already in place. And the mayor of Malargüe was on board with the project.

Construction was completed in 2008. The array is now 3000 square kilometers (more than 1000 square miles) in size and consists of more than 1600 detectors.

The observatory uses two different methods for detecting cosmic rays: “surface detectors,” which track particles that pass through large water-filled tanks, and “fluorescence detectors,” which pick up on the ultraviolet light emitted when cosmic particles interact with nitrogen in Earth’s atmosphere.

Argentinian scientists and engineers have played a major role in both the construction of Pierre Auger and the ongoing research at the observatory. According to Allekotte, approximately 10 to 15 percent of the institutions the observatory hosts are from Argentina. The rest are from 16 other countries.

Carla Bonifazi, a physicist at the Federal University of Rio de Janeiro, says that she chose to complete her doctoral studies at Pierre Auger because it allowed her to work on the first big international particle physics collaboration in Argentina. “This was a big opportunity,” Bonifazi says. “I was there at the right moment.”

Soon after Pierre Auger commenced operations, the National University of Cuyo—which is based in Mendoza, a large city 400 kilometers (approximately 250 miles) away from the observatory—opened a regional branch in Malargüe. “This is not necessarily related to the observatory, but I think the fact that the observatory was there had a strong influence,” Allekotte says. “And often engineers and scientists working at the observatory teach at the university.”

In addition to cosmic-ray physics, scientists and engineers at Pierre Auger have been involved with several side projects. They have worked on atmospheric monitoring programs using instruments set up on site, and they have provided services and infrastructure for seismic projects and satellite programs. “When we set up such an observatory, it turns out to have quite some byproducts that make it interesting and multidisciplinary,” Allekotte says.

A small, international city

Since Pierre Auger’s launch, Malargüe’s population has continued to grow; today more than 27,000 people call it home. Many foreign scientists have travelled to the city to work at the observatory. Once or twice a year, more than 100 international collaborators gather there for scientific meetings.

“When the observatory started, all the international visitors going to the restaurants and hotels and walking on the streets were a bit strange for the people of Malargüe,” says Gualberto Ávila, the site manager at Pierre Auger Observatory.

Still, staff at Pierre Auger have made efforts to encourage such interactions. “In the beginning, we thought about having guest rooms for visiting scientists on site,” Allekotte recalls. “But we then discarded this idea and decided to get people who come to the observatory rent their apartment or housing in the town.”

Allekotte believes that was a good decision because this allowed for foreign academics to interact more closely with the people in the town of Malargüe—leading to, for example, impromptu waitstaff science lectures.

Pierre Auger has changed the lives of citizens of Malargüe in a variety of ways.

Scientists at the observatory have donated money, books and educational materials to the local schools. In 2006, the town inaugurated the James W. Cronin School, a secondary school named after the physicist for his contributions to the local community.

When a powerline was installed to power the detectors at the observatory, many rural homes were also connected to the grid for the first time. “I think this was the most important impact for the infrastructure in the area,” Ávila says.

The Pierre Auger Observatory was initially set to run until 2015, but the international collaboration agreed to upgrade the facilities and extend its life for at least another 10 years.

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Artwork by Sandbox Studio, Chicago with Pedro Rivas

Following the science

A visitor center in Malargüe provides information about Pierre Auger Observatory and cosmic-ray physics. Since 2001 it has welcomed more than 100,000 people from both around Argentina and abroad. Science fairs held every few years by the observatory have also attracted students and teachers from all around the country.

Cosmic-ray science has seeped into everyday life in Malargüe, Allekotte says. “The city of Malargüe promotes itself as a city for scientific tourism,” he says. “The observatory plays a big role in giving the town this characteristic.”

For its part, Chile now has at least 10 tourism-specific astronomical observatories where amateur stargazers can peer through telescopes to get a closer look at the night sky. The professional observatories also consider outreach to the local community to be key to their missions.

According to Rubio, the regions that house these facilities have also benefitted economically from the influx of tourists, especially during special events, such as the total solar eclipse that passed through parts of Chile and Argentina in July 2019.

The rapid progression of astronomy in Chile has also been met by a growth public interest in the science, Rubio says. “Today, we see news about astronomy almost daily. Chile’s very good skies and astronomical facilities have become part of the national identity.”

See the full article here .


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Symmetry is a joint Fermilab/SLAC publication.


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