From Imperial College London: “Young star caught forming around another star”

From Imperial College London

14 December 2018
Hayley Dunning

A small star has been observed forming out of the dust surrounding a larger star, in a similar way to how planets are born.

Astronomers were observing the formation of a massive young star, called MM 1a, when they discovered an unexpected object nearby.

MM 1a is surrounded by rotating disc of gas and dust. But orbiting just beyond this disc, they discovered a faint object they called MM 1b, which they discovered was a smaller star. MM 1b is believed to have formed out of the gas and dust surrounding the larger MM 1a.

The team of astronomers, led by the University of Leeds and including an Imperial College London researcher, have published their discovery today in the journal Astrophysical Journal Letters.

Co-author Dr Thomas Haworth, from the Department of Physics at Imperial, helped predict what might be observed around MM 1a, and then to interpret what they actually found. He said: “It’s great when the new data surprises you, which was definitely the case here.

“Seeing the disc itself in so much detail is exciting, but detecting a second star forming within the disc, perhaps in a similar way to how planets form, was a huge unexpected bonus. There is a lot of work ahead of us to fully understand the consequences of this new discovery.”

An entirely different formation process

Stars form within large clouds of gas and dust in interstellar space. When these clouds collapse under gravity, they begin to rotate faster, forming a disc around them. It is in these discs that planets can form around low mass stars like our Sun.

Lead author Dr John Ilee, from the School of Physics and Astronomy at the University of Leeds, said: “In this case, the star and disc we have observed is so massive that, rather than witnessing a planet forming in the disc, we are seeing another star being born.”

By measuring the amount of radiation emitted by the dust and subtle shifts in the frequency of light emitted by the gas, the researchers were able to calculate the mass of MM 1a and MM 1b.

They found that MM 1a weighs 40 times the mass of our Sun. The smaller orbiting star MM 1b was calculated to weigh less than half the mass of our Sun.

Observation of the dust emission (green) and hot gas rotating in the disc around MM 1a (red is receding gas, blue is approaching gas). MM 1b is seen the lower left. Credit: J. D. Ilee / University of Leeds.

Dr Ilee said: “Many older massive stars are found with nearby companions. But these ‘binary’ stars are often very equal in mass, and so likely formed together as siblings. Finding a young binary system with a mass ratio of 80:1 is very unusual, and suggests an entirely different formation process for both objects.”

The team believe stars like MM 1b could form in the outer regions of cold, massive discs. These discs are unable to hold themselves up against the pull of their own gravity, collapsing into one or more fragments.

The team believe their discovery is one of the first examples of a ‘fragmented’ disc to be detected around a massive young star.

Only a million years to live

Dr Duncan Forgan, a co-author from the Centre for Exoplanet Science at the University of St Andrews, added: “I’ve spent most of my career simulating this process to form giant planets around stars like our Sun. To actually see it forming something as large as a star is really exciting.”

The researchers note that newly discovered young star MM 1b could also be surrounded by its own disc, which may have the potential to form planets of its own – but it will need to be quick.

Dr Ilee added: “Stars as massive as MM 1a only live for around a million years before exploding as powerful supernovae, so while MM 1b may have the potential to form its own planetary system in the future, it won’t be around for long.”

The astronomers made this surprising discovery by using a unique new instrument situated high in the Chilean desert – the Atacama Large Millimetre/submillimetre Array (ALMA).

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

Using the 66 individual dishes of ALMA together in a process called interferometry, the astronomers were able to simulate the power of a single telescope nearly 4km across, allowing them to image the material surrounding the young stars for the first time.

Funders for this research include the Science and Technologies Facilities Council (UK) and the European Research Council.

See the full article here .

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Imperial College London is a science-based university with an international reputation for excellence in teaching and research. Consistently rated amongst the world’s best universities, Imperial is committed to developing the next generation of researchers, scientists and academics through collaboration across disciplines. Located in the heart of London, Imperial is a multidisciplinary space for education, research, translation and commercialisation, harnessing science and innovation to tackle global challenges.

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From ALMA: “ALMA Campaign Provides Unprecedented Views of the Birth of Planets”

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

From ALMA

12 December, 2018

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

Laura Pérez
Department of Astronomy, University of Chile
Santiago, Chile
Cell phone: +5699494640
Email: lperez@das.uchile.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

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

ALMA’s high-resolution images of nearby protoplanetary disks, which are results of the Disk Substructures at High Angular Resolution Project (DSHARP). Credit: ALMA (ESO/NAOJ/NRAO), S. Andrews et al.; N. Lira

Animated GIF showing the ALMA images of 20 protoplanetary disks observed by DSHARP project. Credit: ALMA (ESO/NAOJ/NRAO), Andrews et al.; N. Lira.

Planets Forming around a Young Star from NRAO Outreach on Vimeo.

ALMA Timelapse for Afterite Ballet from ALMA Observatory on Vimeo.

Reel drone flight over ALMA antennas from ALMA Observatory on Vimeo.

Astronomers have already cataloged nearly 4,000 exoplanets in orbit around distant stars. Though we have learned much about these newfound worlds, there is still much we do not know about the steps of planet formation and the precise cosmic recipes that spawn the wide array of planetary bodies we have already uncovered, including so-called hot Jupiters, massive rocky worlds, icy dwarf planets, and – hopefully someday soon – distant analogs of Earth.

To help answer these and other intriguing questions about the birth of planets, a team of astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA)has conducted one of the deepest surveys ever of protoplanetary disks, the planet-forming dust belts around young stars.

“This specific Large Programis important because it takes one of the fundamental science goals of ALMA, which is to understand the process of planet formation and takes it from previous studies, which were either very small samples or single objects, to a completely new context, allowing statistical views” explains Stuartt Corder, Deputy Director of ALMA; “Are these kinds of structures common or rare? This more statistical approach allows researchers to answer questions that are much more fundamental to the process of planet formation.”

Known as the Disk Substructures at High Angular Resolution Project (DSHARP), this Large Programof ALMA has yielded stunning, high-resolution images of 20 nearby protoplanetary disks and given astronomers new insights into the variety of features they contain and the speed with which planets can emerge.

The results of this survey are contained in a series of ten papers that are accepted for publication in The Astrophysical Journal Letters. Link to .pdf https://arxiv.org/pdf/1812.04045.pdf

According to the researchers, the most compelling interpretation of these observations is that large planets, likely similar in size and composition to Neptune or Saturn, form quickly, much faster than current theory would indicate. The also tend to form in the outer reaches of their solar systems at tremendous distances from their host stars.

Such precocious formation could also help explain how rocky, Earth-size worlds are able to evolve and grow, surviving their presumed self-destructive adolescence.

“The goal of this months-long observing campaign was to search for structural commonalities and differences in protoplanetary disks. ALMA’s remarkably sharp vision has revealed previously unseen structures and unexpectedly complex patterns,” said Sean Andrews, an astronomer at the Harvard-Smithsonian Center for Astrophysics (CfA) and a leader of the ALMA observing campaign along with Andrea Isella of Rice University and Cornelis Dullemond of Heidelberg University. “We are seeing distinct details around a wide assortment of young stars of various masses. The most compelling interpretation of these highly diverse, small-scale features is that there are unseen planets interacting with the disk material.”

The leading models for planet formation hold that planets are born by the gradual accumulation of dust and gas inside a protoplanetary disk, beginning with grains of dust that coalesce to form larger and larger rocks, until asteroids, planetesimals, and planets emerge. This hierarchical process should take many millions of years to unfold, suggesting that its impact on protoplanetary disks would be most prevalent in older, more mature systems. Mounting evidence, however, indicates that is not always the case.

ALMA’s early observations of young protoplanetary disks, some only about one million years old, reveal striking and surprising structures, including prominent rings and gaps, which appear to be the hallmarks of planets. Astronomers were initially cautious to ascribe these features to the actions of planets since other natural process could be at play.

“It was surprising to see possible signatures of planet formation in the very first high-resolution images of young disks. It was important to find out whether these were anomalies or if those signatures were common in disks,” said Jane Huang, a graduate student at CfA and a member of the research team.

Since the sample set was so small, however, it was impossible to draw any overarching conclusions. It could have been that astronomers were observing atypical systems. More observations on a variety of protoplanetary disks were needed to determine the most likely cause of the features we were seeing.

The DSHARP campaign was designed to do precisely that by studying the relatively small-scale distribution of dust particles around 20 nearby protoplanetary disks. These dust particles naturally glow in millimeter-wavelength light, enabling ALMA to precisely map the density distribution of small, solid particles around young stars.

Depending on the star’s distance from Earth, ALMA was able to distinguish features as small as a few Astronomical Units(An Astronomical Unit is the average distance of the Earth to the Sun – about 150 million kilometers, which is a useful scale for measuring distances on the scale of star systems). Using these observations, the researchers were able to image an entire population of nearby protoplanetary disks and study their AU-scale features.

The researchers found that many substructures – concentric gaps, narrow rings – are common to nearly all the disks, while large-scale spiral patterns and arc-like features are also present in some of the cases. Also, the disks and gaps are present at a wide range of distances from their host stars, from a few AU to more than 100 AU, which is more than three times the distance of Neptune from our Sun.

These features, which could be the imprint of large planets, may explain how rocky Earth-like planets are able to form and grow. For decades, astronomers have puzzled over a major hurdle in planet-formation theory: Once planetesimals grow to a certain size – about one kilometer is diameter – the dynamics of a smooth protoplanetary disk would induce them to fall in on their host star, never acquiring the mass necessary to form planets like Mars, Venus, and Earth.

The dense rings of dust we now see with ALMA would produce a safe haven for rocky worlds to fully mature. Their higher densities and the concentration of dust particles would create perturbations in the disk, forming zones where planetesimals would have more time to grow into fully fledged planets.

“When ALMA truly revealed its capabilities with its iconic image of HL Tau, we had to wonder if that was an outlier since the disk was comparatively massive and young,” noted Laura Perez with the University of Chile and a member of the research team. “These latest observations show that, though striking, HL Tau is far from unusual and may actually represent the normal evolution of planets around young stars.”

Additional Information

This research is presented in the following papers accepted to the Astrophysical Journal Letters.

“The Disk Substructures at High Angular Resolution Project (DSHARP): I. Motivation, Sample, Calibration, and Overview: S. Andrews, et al.
“The Disk Substructures at High Angular Resolution Project (DSHARP): II. Characteristics of Annular Substructures,” J. Huang, et al.
“The Disk Substructures at High Angular Resolution Project (DSHARP): III. Spiral Structures in the Millimeter Continuum of the Elias 27, IM Lup, and WaOph 6 Disks,” J. Huang, et al.
“The Disk Substructures at High Angular Resolution Project (DSHARP): IV. Characterizing Substructures and Interactions in Disks around Multiple Star Systems,” N. Kurtovic, et al.
“The Disk Substructures at High Angular Resolution Project (DSHARP): V. Interpreting ALMA Maps of Protoplanetary Disks in Terms of a Dust Model” T. Birnstiel, et al.
“The Disk Substructures at High Angular Resolution Project (DSHARP): VI. Dust Trapping in Thin-Ringed Protoplanetary Disks,” C. Dullemond, et al.
“The Disk Substructures at High Angular Resolution Project (DSHARP): VII. The Planet-Disk Interactions Interpretation” S. Zhang, et al.
“The Disk Substructures at High Angular Resolution Project (DSHARP): VIII. The Rich Ringed Substructures in the AS 209 Disk,” V, Guzmán, et al.
“The Disk Substructures at High Angular Resolution Project (DSHARP): IX. A High Definition Study of the HD 163296 Planet Forming Disk” A. Isella, et al.
“The Disk Substructures at High Angular Resolution Project (DSHARP): X. Multiple Rings, a Misaligned Inner Disk, and a Bright Arc in the Disk around the T Tauri Star HD 143006,” L. Pérez, et al.

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 ALMA via Science News: “Astronomers find far-flung wind from a black hole in the universe’s first light”

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

From ALMA

via

Science News

December 5, 2018
Lisa Grossman

The discovery could shed light on how galaxies and black holes grow up together.

A MIGHTY WIND Supermassive black holes in the centers of galaxies can blow gas and plasma far away from their galaxies, as shown in this artist’s illustration based on the Pinwheel galaxy. NASA JPL-Caltech

Astronomer Mark Lacy and colleagues used the Atacama Large Millimeter Array in Chile to observe the universe’s first light, and found evidence of gusts flowing from a type of black hole called a quasar. The wind extends about 228,000 light-years away from the galaxy that surrounds the quasar. Previously, astronomers had seen signs of these winds only about 3,000 light-years from their galaxies.

The result, published [MNRAS] November 12 could help resolve questions about how black holes can grow with their galaxies, or shut galaxies down for good.

Black holes are best known for gravitationally gobbling everything that veers too close. Paradoxical as it sounds, supermassive black holes can also send material in the opposite direction, driving powerful flows of charged gas and plasma away from their host galaxies.

These black holes are victims of their own success, pulling in more material than they can consume at once. The excess material surrounds black holes in a tight swirling disk, where friction heats it to hundreds of millions of degrees Celsius. The black hole plus that bright disk is a quasar.

All that heat, plus some help from magnetic fields [Nature] , create great gusts that carry gas and plasma away (SN Online: 3/6/17). “The black hole can’t swallow all of that stuff,” says Lacy, of the National Radio Astronomy Observatory in Charlottesville, Va. “It has to blow some of it out.”

Measuring such winds’ extent and energies could help scientists figure out how material spit out by the black holes might influence the way the galaxies grow and evolve. If the wind doesn’t blow far enough from the galaxy, for example, the material in the gusts could fall back down into the galaxy and be recycled into new stars — or blown back out again [Nature] (SN: 7/21/18, p. 16).

But if a black hole’s wind is too powerful, it could steal all of a galaxy’s star-forming gas and shut the galaxy down. That could explain why there appears to be a mass limit for galaxies: Most have fewer than 10 trillion times the sun’s mass worth of stars. Theoretical calculations suggest that if a black hole can blow away 1 or 2 percent of the total energy of a quasar in the wind, that would be enough to shut a galaxy down. And that might just happen to be when a galaxy weighs about 10 trillion suns.

To figure out if that actually happens, however, astronomers need to know how far away real black holes’ winds can reach and how much energy they carry.

Lacy and his colleagues observed a quasar called HE 0515-4414, about 268 million light-years away from Earth, to see how the hot gas of its wind scattered photons from the cosmic microwave background, the oldest light in the universe (SN Online: 7/24/18). “It’s almost like the wind casts a shadow,” Lacy says. “You see this hole in the microwave background.”

This phenomenon is called the Sunyaev-Zeldovich effect. Other astronomers predicted in 1999 that the effect could be used to measure the energies and extents of these winds. But ALMA is the first telescope sensitive enough to detect the effect.

In addition to tracking how far HE 0515-4414’s wind blows, the team also measured the gust’s energy. It was much less than expected, about 0.01 percent of the quasar’s total energy. That’s nowhere near enough to explain the galaxy mass limit.

“That doesn’t mean the theory is completely dead,” Lacy says. The ALMA observations suggested that, rather than blowing continuously, the wind blew a large, long-lived bubble of material that can last for many millions of years, longer than most quasars are active. That bubble could keep star-forming material out of the galaxy indefinitely, shutting the galaxy down even without an actively blowing black hole.

“To me that’s the next frontier, to find these ghost outflows hanging around quasars that might be dead,” says astrophysicist Priyamvada Natarajan of Yale University, who wrote the 1999 paper predicting this observation method as a graduate student at the Institute of Astronomy at the University of Cambridge.

“I’m very excited,” she says. “This is the first detection where we can actually measure how much kinetic energy is being transmitted to the environment of the galaxy.” But she cautions that the new study focuses on only one object. Astronomers will need to find more quasar winds before drawing conclusions on how black holes affect their galaxies in general.

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 ALMA: “Magnetic fields found in a Jet from a Baby Star”

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

From ALMA

28 November, 2018

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 –
Phone: +81 422 34
Email: hiramatsu.masaaki@nao.ac.jp

Calum
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

An international research team led by Chin-Fei Lee in the Academia Sinica Institute of Astronomy and Astrophysics (ASIAA) has made a breakthrough observation with the Atacama Large Millimeter/submillimeter Array (ALMA), confirming the presence of magnetic fields in a jet from a protostar (baby star). The jet is believed to play an important role in star formation, enabling the protostar to accrete mass from an accretion disk by carrying away angular momentum from the disk. It is highly supersonic and collimated, and predicted, in theory, to be launched and collimated by magnetic fields. The finding supports the theoretical prediction and confirms the role of the jet in star formation.

“Although it has been long predicted that protostellar jet is threaded with magnetic fields, no one is really sure about it. Thanks to the high-sensitivity of ALMA, we have finally confirmed the presence of magnetic fields in a protostellar jet with molecular line polarization detection. More interestingly, the magnetic fields in the jet could be helical, as seen in the jet from an active galactic nucleus (AGN). Perhaps, the same mechanism is at work to launch and collimate the jets from both protostar and AGN,” says Chin-Fei Lee at ASIAA.

“The detected polarization comes from a silicon monoxide (SiO) molecular line in the presence of magnetic fields”, says Hsiang-Chih Hwang, who was a former National Taiwan University (NTU) undergraduate student of Chin-Fei Lee modeling the polarization. “The polarized emission in the jet is so faint that we failed to detect it with the Submillimeter Array (SMA, Mauna Kea, Hawai). We are so excited to have finally detected it with ALMA.”

HH 211 is a well-defined jet from one of the youngest protostellar systems in Perseus at a distance of about 1,000 light-years. The central powering protostar has an age of only about 10,000 years (which is about 2 millionths of the age of our Sun) and a mass of about 0.05 solar mass. The jet is rich in SiO molecular gas and drives a spectacular molecular outflow around it (see the top panel in Figure 1).

With ALMA, we zoomed in to the innermost part of the jet within 700 au of the central protostar, where the emission is the brightest in SiO. We detected SiO line polarization toward the approaching (blueshifted) side of the jet (see the bottom panel in Figure 1). The polarization has a fraction of about 1.5% and an orientation roughly aligned with the jet axis. This line polarization is due to the Goldreich-Kylafis effect, confirming the presence of magnetic fields in the jet. The orientation of the magnetic fields could be either toroidal or poloidal. According to the current jet launching models, the magnetic fields are expected to be helical and should be mainly toroidal there where the polarization is detected, in order to collimate the jet. Deeper observations will be proposed to detect the line polarization in the receding (redshifted) side of the jet and check for consistent morphology of the polarization. Furthermore, additional SiO lines will be observed in order to confirm the field morphology.

The observation opens up an exciting possibility of directly detecting and characterizing magnetic fields in protostellar jets through high-resolution and high-sensitivity imaging with ALMA, which can improve the theories of jet formation and thus our understanding for the feeding process in the innermost region of star formation.

This research was presented in a paper titled “Unveiling a Magnetized Jet from a Low-Mass Protostar” by Lee et al. published in the Nature Communications 2018 November issue.

The team is composed of Chin-Fei Lee (ASIAA, Taiwan; National Taiwan University, Taiwan), Hsiang-Chih Hwang (National Taiwan University, Taiwan; Johns Hopkins University, USA), Tao-Chung Ching (National Tsing Hua University, Taiwan), Naomi Hirano (ASIAA, Taiwan), Shih-Ping Lai (National Tsing Hua University, Taiwan), Ramprasad Rao (ASIAA, Taiwan), and Paul T.P. Ho (ASIAA, Taiwan; East Asia Observatory)

Images

Figure 1: ALMA detection of SiO line polarization in the HH 211 jet. (Top) A composite image showing the HH 211 jet and the outflow around it. The blue and red images show respectively the approaching (blueshifted) side and the receding (redshifted) side of the jet in SiO (adopted from Lee et al. 2009). Gray image shows the outflow in H2 (adopted from Hirano et al. 2006). (Bottom) A zoom-in to the innermost part of the jet within 700 au of the central protostar. Orange image shows the accretion disk recently detected with ALMA (Lee et al. 2018). Blue and red images show the blueshifted and redshifted sides of the innermost jet coming out from the disk, obtained in our observation. Yellow line segments show the orientations of the SiO line polarization in the jet. A size scale of our solar system is shown in the lower right corner for size comparison. In the two panels, asterisks mark the possible position of the central protostar. Credit: ALMA (ESO/NAOJ/NRAO)/Lee et al.

Figure 2: Possible helical magnetic fields in the HH 211 jet. Blue and red images show the blueshifted and redshifted sides of the jet coming out from the disk, as shown in the bottom panel of Figure 1. The greenish helical lines show the possible magnetic field morphology in the jet. The asterisk marks the possible position of the central protostar. A size scale of our solar system is shown in the lower right corner for size comparison. Credit: ALMA (ESO/NAOJ/NRAO)/Lee et al.

Figure 3: Artist’s conception of the helical magnetic field in the jet coming from the accretion disk. Credit: Yin-Chih Tsai

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 ALMA: “ALMA’s Highest Frequency Receiver produces its First Scientific Result on Massive Star Formation”

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

From ALMA

The Atacama Large Millimeter/submillimeter Array (ALMA) has opened another new window to the Universe. Using its highest frequency receivers yet, researchers obtained 695 radio signals from various molecules, including simple sugar, in the direction of a massive star forming region, and revealed a pair of water vapor fountains erupting from the region. These first scientific results from the ALMA Band 10 receivers developed in Japan ensure a promising future for high frequency observations.

Photo of the star forming region NGC 6334I, also known as the Cat’s Paw Nebula, taken by the NASA/ESA Hubble Space Telescope (top) and the high frequency radio spectra (bottom). The blue line shows the spectral lines detected by ALMA and the gray line shows the lines detected by the European Space Agency’s Herschel Space Observatory. The ALMA observations detected more than ten times as many spectral lines. Note that the Herschel data have been inverted for comparison. Two molecular lines are labeled for reference.
Credit: S. Lipinski/NASA & ESA, NAOJ, NRAO/AUI/NSF, B. McGuire et al.

The institutes participating in ALMA have shared responsibility for developing dedicated radio receivers for each of ALMA’s 10 frequency bands. The National Astronomical Observatory of Japan (NAOJ) developed receivers for three bands; Band 4 (125-163 GHz), Band 8 (385-500 GHz), and Band 10 (787 to 950 GHz). The Band 10 receiver covers the highest frequency range in ALMA, which has not yet been extensively observed with other ground-based telescopes.

ALMA Band 10 receiver
Credit:ALMA (ESO/NAOJ/NRAO)

“High-frequency radio observations like in Band 10 are normally not possible from the ground,” said Brett McGuire, a chemist at the National Radio Astronomy Observatory in Charlottesville, Virginia, and lead author on a paper in The Astrophysical Journal Letters. “They require the extreme precision and sensitivity of ALMA, along with some of the driest and most stable atmospheric conditions that can be found on Earth.”

ALMA is a supremely sensitive cosmic chemical sensor. As molecules tumble and vibrate in space, they naturally emit electromagnetic radiation at specific frequencies, which appear as spikes on a spectrum. Each of ALMA’s receiver bands can detect a different selection of these unique spectral fingerprints. The highest frequencies offer unique insight into lighter, important chemicals, like heavy water (HDO), as well as complex, warm molecules.

McGuire and his team observed NGC 6634I, a nursery cloud of massive stars, with ALMA in 880 GHz. NGC 6334I is part of the Cat’s Paw Nebula located 4,300 light-years away from Earth. “We detected a wealth of complex organic molecules surrounding this massive star-forming region,” said McGuire. “These results have been received with excitement by the astronomical community and show once again how ALMA will reshape our understanding of the universe.”

The European Space Agency’s Herschel Space Observatory has observed NGC 6334I in the same frequency range and detected 65 molecular emission lines. On the other hand, ALMA detected 695, 10 times as many spectral lines as Herschel. ALMA’s prominent sensitivity and resolution offers a new level of astrochemistry research.

The molecules detected in the direction of NGC 6334I include methanol, ethanol, methylamine, and glycolaldehyde, the simplest sugar-related molecule. Glycolaldehyde has already been detected around small baby stars in the IRAS 16293-2422 system with ALMA at a lower frequency. The difference in frequency reflects a difference in the environment. With Band 10 receivers, astronomers obtained a new tool to investigate warmer, denser regions.

The other Band 10 result was also one of the most challenging, the direct observation of jets of water vapor streaming away from one of the massive protostars in NGC 6334I. ALMA was able to detect the high frequency radio waves naturally emitted by heavy water (water molecules made up of oxygen, hydrogen, and deuterium atoms, which are hydrogen atoms with a proton and a neutron in their nuclei).

As a star begins to form out of massive clouds of dust and gas, the material surrounding the star falls onto the mass at the center. A portion of this material, however, is propelled away from the growing protostar as a pair of jets, which carry away gas and molecules, including water.

The heavy water the researchers observed is flowing away from either a single protostar or a small cluster of protostars. These jets are oriented differently from what appear to be much larger and potentially more-mature jets emanating from the same region. The astronomers speculate that the heavy-water jets seen by ALMA are relatively recent features just beginning to move out into the surrounding nebula.

Composite ALMA image of NGC 6334I, a star-forming region in the Cat’s Paw Nebula, taken with the Band 10 receivers, ALMA’s highest-frequency vision. The blue component is heavy water (HDO) streaming away from either a single protostar or a small cluster of protostars. The orange region is the “continuum emission” in the same region, which scientists found is extraordinarily rich in molecular fingerprints, including glycoaldehyde, the simplest sugar-related molecule.
Credit: ALMA (ESO/NAOJ/NRAO): NRAO/AUI/NSF, B. Saxton

“It is with much pleasure that we see the first scientific result from the ALMA Band 10 receiver,” said Yoshinori Uzawa, the Director of the NAOJ Advanced Technology Center. He is an engineering researcher specializing in superconducting devices and led the Band 10 receiver development. “I have devoted myself to the research of superconducting devices for more than two decades, and the Band 10 receiver is one of the fruits of my work and the efforts of many staffs, including the Band 10 development team and the commissioning team in Chile. I’d like to express my appreciation to all, and I am looking forward to seeing yet more new insights into the Universe.”

Development of the ALMA receivers was not easy, especially for Band 10. Due to its extreme high frequency, researchers could not use the conventional superconducting devices made of Niobium. The development team made a high quality film from the compound superconductive material NbTiN (niobium-titanium nitrides) in cooperation with the National Institute of Information and Communication Technology to achieve the world’s highest performance in the frequency of Band 10 in 2009. The team finished manufacturing and shipping the 73 receiver cartridges in 2014. After extensive commissioning and test observation on site, the Band 10 receivers have been used in ALMA’s normal science operation since October 2015.

The research team members are:

Brett A. McGuire (National Radio Astronomy Observatory / Harvard-Smithsonian Center for Astrophysics), Crystal L. Brogan (National Radio Astronomy Observatory), Todd R. Hunter (National Radio Astronomy Observatory), Anthony J. Remijan (National Radio Astronomy Observatory), Geoffrey A. Blake (California Institute of Technology), Andrew M. Burkhardt (University of Virginia / Harvard-Smithsonian Center for Astrophysics), P. Brandon Carroll (Harvard-Smithsonian Center for Astrophysics), Ewine F. van Dishoeck (Leiden University), Robin T. Garrod (University of Virginia), Harold Linnartz (Leiden University), Christopher N. Shingledecker (University of Virginia / University of Stuttgart), Eric R. Willis (University of Virginia)

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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: “Trans-galactic Streamers Feeding Most Luminous Galaxy in the Universe”

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

From ALMA

15 November, 2018

Tanio Díaz-Santos
Postdoctoral Fellow ALMA-CONICYT
Universidad Diego Portales, Santiago, Chile
Phone: +56 2 2213 0480
Cell phone: +56 9 9386 0003
Email: tanio.diaz@mail.udp.cl

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

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

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

Calla Cofield
Jet Propulsion Laboratory, Pasadena, California
Phone: +1 626 808 2469
Email: calla.e.cofield@jpl.nasa.gov

ALMA image of W2246-0526 and its companions feeding it through trans-galactic streamers. Credit: T. Diaz-Santos et al.; N. Lira; ALMA (ESO/NAOJ/NRAO).

ALMA image shows how W2246-0526 is being fed by three companion galaxies (C1, C2, and C3) through trans-galactic streamers: a large tidal tail, labeled in green, connects C2 with the main galaxy; the other two galaxies (C1 and C3) are connected to W2246-0526 by dust bridges. Credit: T. Diaz-Santos et al.; N. Lira; ALMA (ESO/NAOJ/NRAO).

This animation shows in blue the Hubble Space Telescopes Observations in the same area of the Sky as ALMA observations (in red and yellow) of W2246-0526.

NASA/ESA Hubble Telescope

The big blue galaxy observed by Hubble is located much closer to Earth than the studied system, hence it is not part of this study. The animation clearly shows how ALMA can observe and reveal these stream-structures where the optics telescopes can’t. Credit: T. Diaz-Santos et al; / Hubble Space Telescope / N. Lira – ALMA (ESO/NAOJ/NRAO).

Artist impression of W2246-0526, the most luminous known galaxy, and three companion galaxies. Credit: NRAO/AUI/NSF, S. Dagnello.

The most luminous galaxy in the universe has been caught in the act of stripping away nearly half the mass from not one, not two, but at least three of its smaller neighbors, according to new Atacama Large Millimeter/submillimeter Array (ALMA) observations published in the journal Science. The light from this galaxy, known as W2246-0526, took 12.4 billion years to reach us, so we see it as it was when our universe was only a tenth of its present age.

Trans-galactic Streamers Feeding Most Luminous Galaxy in the Universe from ALMA Observatory

The new observations with ALMA reveal distinct streamers of material being pulled from three smaller galaxies and flowing into the more massive galaxy, which was discovered in 2015 by NASA’s space-based Wide-field Infrared Survey Explorer (WISE).

NASA Wise Telescope

It is by no means the largest or most enormous galaxy we know of, but it is unrivaled in its brightness, emitting as much infrared light as 350 trillion Suns.

The connecting tendrils between the galaxies contain about as much material as the galaxies themselves. ALMA’s amazing resolution and sensitivity allowed the researchers to detect these remarkably faint and distant trans-galactic streamers.

“We knew from previous data that there were three companion galaxies, but there was no evidence of interactions between these neighbors and the central source,” said Tanio Diaz-Santos of the Universidad Diego Portales in Santiago, Chile, lead author of the study. “We weren’t looking for cannibalistic behavior and weren’t expecting it, but this deep dive with the ALMA observatory makes it very clear.”

Galactic cannibalism is not uncommon, though this is the most distant galaxy in which such behavior has been observed, and the study authors are not aware of any other direct images of a galaxy simultaneously feeding on material from multiple sources at those early cosmic times.

The researchers emphasize that the amount of gas being devoured by W2246-0526 is enough to keep it forming stars and feeding its central black hole for hundreds of millions of years.

This galaxy’s startling luminosity is not due to its individual stars. Instead, its brightness is powered by a tiny, yet fantastically energetic disk of gas that is being superheated as it spirals in on the supermassive black hole. The light from this blazingly bright accretion disk is then absorbed by the surrounding dust, which re-emits the energy as infrared light.

The material from the accretion disks falls onto the black hole powering the Active Galactic Nuclei (AGN), making this galaxy one of a rare class of quasars known as Hot, Dust-Obscured Galaxies (Hot DOGs). Only about one out of every 3,000 quasars observed by WISE belongs to this class.

Much of the dust and gas being siphoned away from the three smaller galaxies is likely being converted into new stars and feeding the more massive galaxy’s central black hole. This galaxy’s gluttony, however, may lead to self-destruction. Previous research [Astrophysical Journal Letters].suggests that the energy of the AGN will ultimately jettison much if not all of the galaxy’s star-forming fuel.

An earlier work led by co-author Chao-Wei Tsai estimates that the black hole at the center of W2246-0526 is about 4 billion times the mass of the Sun. The mass of the black hole directly influences how bright the AGN can become, but the paper shows that W2246-0526 is about three times more luminous than what should be possible. Solving this apparent contradiction will require more observations.

Additional Information

The research team was composed by T. Díaz-Santos [1], R. J. Assef [1], A. W. Blain [2], M. Aravena [1], D. Stern [3], C.-W. Tsai [4], P. Eisenhardt [3], J. Wu [5], H. Jun [6], K. Dibert [7], H. Inami [8], G. Lansbury [9], F. Leclercq [8].

[1] Núcleo de Astronomía, Facultad de Ingeniería y Ciencias. Universidad Diego Portales, Ejército Libertador 441, Santiago, 8320000, Chile.

[2] University of Leicester, Physics and Astronomy, University Road, Leicester LE1 7RH, UK.

[3] Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., Pasadena, CA 91109, USA.

[4] Department of Physics and Astronomy, University of California, Los Angeles, CA 90095, USA.

[5] National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100012, China.

[6] School of Physics, Korea Institute for Advanced Study, 85 Hoegiro, Dongdaemun-gu, Seoul 02455, Korea.

[7] Department of Physics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA.

[8] Univ Lyon, Univ Lyon1, École Normale Supérieure de Lyon, Centre National de la Recherche Scientifique, Centre de Recherche Astrophysique de Lyon UMR5574, F-6~9230, Saint-Genis- Laval, France.

[9] Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge, CB3 0HA, UK.

NASA’s Jet Propulsion Laboratory in Pasadena, California, managed and operated WISE for NASA’s Science Mission Directorate in Washington. The spacecraft operated until 2011. In September 2013, WISE was reactivated, renamed NEOWISE and assigned a new mission to assist NASA’s efforts to identify potentially hazardous near-Earth objects.

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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 ESO and ALMA: “ALMA and MUSE Detect Galactic Fountain-Galaxy-Scale Fountain Seen in Full Glory”

From European Southern Observatory

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

From ALMA

6 November 2018
ESO Contacts

Grant Tremblay
Harvard-Smithsonian Center for Astrophysics
Cambridge, USA
Tel: +1 207 504 4862
Email: grant.tremblay@cfa.harvard.edu

Francoise Combes
LERMA, Paris Observatory
Paris, France
Email: francoise.combes@obspm.fr

Calum Turner
ESO Public Information Officer
Garching bei München, Germany
Tel: +49 89 3200 6670
Email: pio@eso.org

ALMA Contacts
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

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

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

Composite image of the Abell 2597 galaxy cluster showing the fountain-like flow of gas powered by the supermassive black hole in the central galaxy. The yellow is ALMA data of the cold gas. The red is data from MUSE on the Very Large Telescope Yepun UT4 showing the hot hydrogen gas in the same region. The extend purple is the extended hot, ionized gas as imaged by the Chandra X-ray Observatory. Credit: ALMA (ESO/NAOJ/NRAO), Tremblay et al.; NRAO/AUI/NSF, B. Saxton; NASA/Chandra; ESO/VLT

NASA/Chandra X-ray Telescope

ALMA image of cold molecular gas in Abell 2597. Credit: ALMA (ESO/NAOJ/NRAO), G. Tremblay et al.

Animation of the MUSE H-alpha data showing the different velocities of material in the “galactic fountain.” Credit: ESO; G. Tremblay et al.

ESO MUSE on the VLT on Yepun (UT4),

ESO MUSE on VLT Yepun UT4

A mere one billion light-years away in the nearby galaxy cluster known as Abell 2597, there lies a gargantuan galactic fountain. A massive black hole at the heart of a distant galaxy has been observed pumping a vast spout of cold molecular gas into space, which then rains back onto the black hole as an intergalactic deluge .The in- and outflow of such a vast cosmic fountain has never before been observed in combination, and has its origin in the innermost 100 000 light-years of the brightest galaxy in the Abell 2597 cluster.

“This is possibly the first system in which we find clear evidence for both cold molecular gas inflow toward the black hole and outflow or uplift from the jets that the black hole launches,” explained Grant Tremblay of the Harvard-Smithsonian Center for Astrophysics and former ESO Fellow, who led this study. “The supermassive black hole at the centre of this giant galaxy acts like a mechanical pump in a fountain.”

Tremblay and his team used ALMA to track the position and motion of molecules of carbon monoxide within the nebula. These cold molecules, with temperatures as low as minus 250–260°C, were found to be falling inwards to the black hole. The team also used data from the MUSE instrument on ESO’s Very Large Telescope to track warmer gas — which is being launched out of the black hole in the form of jets.

“The unique aspect here is a very detailed coupled analysis of the source using data from ALMA and MUSE,” Tremblay explained. “The two facilities make for an incredibly powerful combination.”

Together these two sets of data form a complete picture of the process; cold gas falls towards the black hole, igniting the black hole and causing it to launch fast-moving jets of incandescent plasma into the void. These jets then spout from the black hole in a spectacular galactic fountain. With no hope of escaping the galaxy’s gravitational clutches, the plasma cools off, slows down, and eventually rains back down on the black hole, where the cycle begins anew.

In an earlier study by the same authors published in the journal Nature, the researchers were able to verify the interconnection between the black hole and the galactic fountain by observing the region across a range of wavelengths, or portions of the spectrum. By studying the location and motion of molecules of carbon monoxide (CO) with ALMA, which shine brightly in millimeter-wavelength light, the researchers could measure the motion of the gas as it falls in toward the black hole.

The ALMA and MUSE data were combined with a new, ultra-deep observation of the cluster by NASA’s Chandra X-ray Observatory, revealing the hot phase of this fountain in exquisite detail, noted the researchers.

This unprecedented observation could shed light on the life cycle of galaxies. The team speculates that this process may be not only common, but also essential to understanding galaxy formation. While the inflow and outflow of cold molecular gas have both previously been detected, this is the first time both have been detected within one system, and hence the first evidence that the two make up part of the same vast process.

Abell 2597 is found in the constellation Aquarius, and is named for its inclusion in the Abell catalogue of rich clusters of galaxies. The catalogue also includes such clusters as the Fornax cluster, the Hercules cluster, and Pandora’s cluster.

More information

This research was presented in a paper entitled “A Galaxy-Scale Fountain of Cold Molecular Gas Pumped by a Black Hole”, which appeared in The Astrophysical Journal.

The team was composed of G. R. Tremblay (Harvard-Smithsonian Center for Astrophysics, Cambridge, USA; Yale Center for Astronomy and Astrophysics, Yale University, New Haven, USA), F. Combes (LERMA, Observatoire de Paris, Sorbonne University, Paris, France), J. B. R. Oonk (ASTRON, Dwingeloo, the Netherlands; Leiden Observatory, the Netherlands), H. R. Russell (Institute of Astronomy, Cambridge University, UK), M. A. McDonald (Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, USA), M. Gaspari (Department of Astrophysical Sciences, Princeton University, USA), B. Husemann (Max-Planck-Institut für Astronomie, Heidelberg, Germany), P. E. J. Nulsen (Harvard-Smithsonian Center for Astrophysics, Cambridge, USA; ICRAR, University of Western Australia, Crawley, Australia), B. R. McNamara (Physics & Astronomy Department, Waterloo University, Canada), S. L. Hamer (CRAL, Observatoire de Lyon, Université Lyon, France), C. P. O’Dea (Department of Physics & Astronomy, University of Manitoba, Winnipeg, Canada; School of Physics & Astronomy, Rochester Institute of Technology, USA), S. A. Baum (School of Physics & Astronomy, Rochester Institute of Technology, USA; Faculty of Science, University of Manitoba, Winnipeg, Canada), T. A. Davis (School of Physics & Astronomy, Cardiff University, UK), M. Donahue (Physics and Astronomy Department, Michigan State University, East Lansing, USA), G. M. Voit (Physics and Astronomy Department, Michigan State University, East Lansing, USA), A. C. Edge (Department of Physics, Durham University, UK), E. L. Blanton (Astronomy Department and Institute for Astrophysical Research, Boston University, USA), M. N. Bremer (H. W. Wills Physics Laboratory, University of Bristol, UK), E. Bulbul (Harvard-Smithsonian Center for Astrophysics, Cambridge, USA), T. E. Clarke (Naval Research Laboratory Remote Sensing Division, Washington, DC, USA), L. P. David (Harvard-Smithsonian Center for Astrophysics, Cambridge, USA), L. O. V. Edwards (Physics Department, California Polytechnic State University, San Luis Obispo, USA), D. Eggerman (Yale Center for Astronomy and Astrophysics, Yale University, New Haven, USA), A. C. Fabian (Institute of Astronomy, Cambridge University, UK), W. Forman (Harvard-Smithsonian Center for Astrophysics, Cambridge, USA), C. Jones (Harvard-Smithsonian Center for Astrophysics, Cambridge, USA), N. Kerman (Yale Center for Astronomy and Astrophysics, Yale University, New Haven, USA), R. P. Kraft (Harvard-Smithsonian Center for Astrophysics, Cambridge, USA), Y. Li (Center for Computational Astrophysics, Flatiron Institute, New York, USA; Department of Astronomy, University of Michigan, Ann Arbor, USA), M. Powell (Yale Center for Astronomy and Astrophysics, Yale University, New Haven, USA), S. W. Randall (Harvard-Smithsonian Center for Astrophysics, Cambridge, USA), P. Salomé (LERMA, Observatoire de Paris, Sorbonne University, Paris, France), A. Simionescu (Institute of Space and Astronautical Science [ISAS], Kanagawa, Japan), Y. Su (Harvard-Smithsonian Center for Astrophysics, Cambridge, USA), M. Sun (Department of Physics and Astronomy, University of Alabama in Huntsville, USA), C. M. Urry (Yale Center for Astronomy and Astrophysics, Yale University, New Haven, USA), A. N. Vantyghem (Physics & Astronomy Department, Waterloo University, Canada), B. J. Wilkes (Harvard-Smithsonian Center for Astrophysics, Cambridge, USA) and J. A. ZuHone (Harvard-Smithsonian Center for Astrophysics, Cambridge, USA).

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ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre EEuropean Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

ESO La Silla HELIOS (HARPS Experiment for Light Integrated Over the Sun)

ESO 3.6m telescope & HARPS at Cerro LaSilla, Chile, 600 km north of Santiago de Chile at an altitude of 2400 metres.

ESO 2.2 meter telescope at La Silla, 600 km north of Santiago de Chile at an altitude of 2400 metres.

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

ESO VLT Platform at Cerro Paranal elevation 2,635 m (8,645 ft)

ESO VLT 4 lasers on Yepun

Glistening against the awesome backdrop of the night sky above ESO_s Paranal Observatory, four laser beams project out into the darkness from Unit Telescope 4 UT4 of the VLT.

ESO/NTT at Cerro La Silla, Chile, at an altitude of 2400 metres

ESO/Vista Telescope at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level

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).

ESO/APEX high on the Chajnantor plateau in Chile’s Atacama region, at an altitude of over 4,800 m (15,700 ft)

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

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: “When Is a Nova Not a ‘Nova’? When a White Dwarf and a Brown Dwarf Collide”

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

From ALMA

8 October, 2018

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

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

ALMA image of CK Vulpeculae. New research indicates that this hourglass-like object is the result of the collision of a brown dwarf and a white dwarf. Credit: ALMA (ESO/NAOJ/NRAO)/S. P. S. Eyres

Using the Atacama Large Millimeter/submillimeter Array (ALMA), an international team of astronomers found evidence that a white dwarf (the elderly remains of a star like the Sun) and a brown dwarf (a failed star without the mass to sustain nuclear fusion) collided in a short-lived blaze of glory that was witnessed on Earth in 1670 as Novasub Capite Cygni (a New Star below the Head of the Swan), which is now known as CK Vulpeculae.

This chart of the position of a nova (marked in red) that appeared in the year 1670 was recorded by the famous astronomer Hevelius and was published by the Royal Society in England in their journal Philosophical Transactions. New observations made with ALMA and other telescopes have now revealed that the star that European astronomers saw was not a nova, but a much rarer, violent breed of stellar collision. It was spectacular enough to be easily seen with the naked eye during its first outburst, but the traces it left were so faint that very careful analysis using submillimetre telescopes was needed before the mystery could finally be unravelled more than 340 years later.

In July of 1670, observers on Earth witnessed a “new star,” or nova, in the constellation Cygnus. Where previously there was dark sky, a bright pinprick of light appeared, faded, reappeared, and then disappeared entirely from view. Modern astronomers studying the remains of this cosmic event initially thought it heralded the merging of two main sequence stars – stars on the same evolutionary path as our Sun.

New observations with ALMA point to a more intriguing explanation. By studying the debris from this explosion, which takes the form of dual rings of dust and gas resembling an hourglass with a compact central object, the researchers concluded that a brown dwarf – a so-called failed star without the mass to sustain nuclear fusion — merged with a white dwarf.

“It now seems what was observed centuries ago was not what we would today describe as a classic ‘nova.’ Instead, it was the merger of two stellar objects, a white dwarf and a brown dwarf. When these two objects collided, they spilled out a cocktail of molecules and unusual isotopes, which gave us new insights into the nature of this object,” said Sumner Starrfield, an astronomer at Arizona State University and co-author on a paper appearing in the Monthly Notices of the Royal Astronomical Society.

According to the researchers, the white dwarf would have been about ten times more massive than the brown dwarf, though much smaller in size. As the brown dwarf spiraled inward, intense tidal forces exerted by the white dwarf would have ripped it apart. “This is the first time such an event has been conclusively identified,” remarked Starrfield.

Since most star systems in the Milky Way are binary, stellar collisions are not that rare, the astronomers note. The new ALMA observations reveal new details about the 1670 event. By studying the light from two, more-distant stars as it shines through the dusty remains of the merger, the researchers were able to detect the telltale signature of the element lithium, which is easily destroyed in the interior of a main sequence star, but not inside a brown dwarf.

“The presence of lithium, together with unusual isotopic ratios of the elements carbon, nitrogen, and oxygen point to material from a brown dwarf star being dumped on the surface of a white dwarf. The thermonuclear ‘burning’ and an eruption of this material resulted in the hourglass we see today,” said Stewart Eyres, Deputy Dean of the Faculty of Computing, Engineering and Science at the University of South Wales and lead author on the paper.

Intriguingly, the hourglass is also rich in organic molecules such as formaldehyde (H2CO) and formamide (NH2CHO), which is derived from formic acid. These molecules would not survive in an environment undergoing nuclear fusion and must have been produced in the debris from the explosion. This lends further support to the conclusion that a brown dwarf met its demise in a star-on-star collision with a white dwarf.

Additional Information

“ALMA Reveals the Aftermath of a White Dwarf—Brown Dwarf Merger in CK Vulpeculae,” Steward Eyres, University of Central Lancashire; Aneurin Evans, Keele University; Albert Zijlstra, Adam Avison, University of Manchester; Robert Gehrz, Charles Woodward, University of Minnesota; Marcin Hajduk, University of Warmia and Mazury; Sumner Starrfield, Arizona State University; Shazrene Mohamed, South African Astronomical Observatory; and R. Mark Wagner, The Ohio State University.

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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: “People Working for ALMA (3) Visualize the invisibles: Professional in Data Analysis to Create Image from Radio Data”

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

From ALMA

ALMA is used by astronomers all over the world. After ALMA observations have been carried out, the data is firstly processed by experts from the ALMA Support Centers, and then the processed data is delivered to astronomers together with radio image data. In an analogy of cooking, the support team is like an assistant who precooks the ingredients. It releases astronomers from complicated processing work and helps them concentrate on their research in exploring the mysteries hidden in the observation data. In the third installment of this series, we interviewed Hiroshi Nagai at NAOJ, who led the Japanese Data Analysis Team, and had talks about the background support work for producing remarkable scientific results with ALMA (Note: as of the date of the interview. Currently Kouichiro Nakanishi takes the leadership.).

Hiroshi Nagai, Project Associate Professor at the NAOJ Chile Observatory. Credit: NAOJ

What is “Seeing Radio Waves”?

— I’d like to start from a very basic question. What does it mean by “seeing radio waves” or “seeing at radio wavelengths”?

Nagai: This is a question we are asked very often. It must be a difficult concept to understand for the general public.

── It feels more like “hearing” radio waves, rather than “seeing”.

Nagai: Thinking of a mobile phone or a radio, it looks like we are “listening” to them. Also, I remember a scene in the old movie “Contact” where the leading character was hearing radio waves coming from the space.

— It’s a science-fiction movie starring Jodie Foster as an astronomer.

Nagai: Right. The leading character receives radio signals sent from an extraterrestrial civilization and listens to them with a headset. But, actually, we astronomers do not listen to radio waves (laugh).

— What are astronomers actually doing then?

Nagai: Let’s put aside the topic of radio telescopes for now. When we “see” things with eyes or with camera, we are getting basically two types of information: one is intensity of light and another is color. Technically speaking, color is the wavelength of light.
Now, putting aside the color, imagine a black and white photo. Each pixel of the photo represents the intensity of light and forms a grayscale image as a whole. Radio observation does exactly the same thing, because it visualizes the intensity of radio waves coming from the universe as an image. Radio waves are invisible to the human eye and we don’t know what color the emission really is, but we can produce a radio image by showing the intensity of radio emission of each pixel in grayscale.

A photo of a spiral galaxy captured with the Subaru Telescope. In an enlarged portion, we can see pixels. The scaling represents the intensity of light. Credit:NAOJ

— Exactly the same as visible light. Very easy to understand.

Nagai: As mentioned earlier, the difference in color is the difference in wavelength. The same is true in radio waves. The role of the radio telescope is to measure the intensity and wavelengths (equivalent to colors) of radio emissions coming from the universe to create two-dimensional image.

— I think I got the meaning of “seeing at radio wavelengths”.

Nagai: It might sound simple, but we actually have complicated process in producing images from radio data received with a telescope. In particular, ALMA consists of 66 parabolic antennas that work as a single giant virtual radio telescope. This system is called “interferometer” and requires very difficult and delicate data handling. That’s why our team conducts reduction and imaging of the data.

“Data reduction team maximizes the scientific output from ALMA”

— In ALMA, obtained data is delivered to researchers after the data reduction team finishes reduction and imaging. What is the situation with other telescopes?

Nagai: As far as I know, ALMA is the only ground-based telescope that reduces all the data and delivers them to researchers, at least in the field of radio telescopes. In general, researches receive raw data obtained by the telescope. That policy is something like “Observation was done. Wishing your data analysis goes well. Good luck!” (laugh)

— Why does ALMA deliver processed data including even image data?

Nagai: The difference between raw data and processed data can be likened to a whole tuna and tuna fillets. If a whole tuna is delivered to your home, you will be at a loss of what to do with it. But if you receive processed tuna fillets, you know how to cook with them. In short, we are doing a cutting part of a whole fish.

— The analogy of a tuna is very easy to understand.

Nagai: It is quite difficult to handle raw ALMA data especially for someone who has no specialized skills in the radio interferometer. We have to avoid situations where researchers have troubles in writing papers with low-quality observation data or due to a lack of knowledge of how to create images. One of our aims is to reduce such situations and make ALMA available to a wide range of people including those who are not experts of the radio interferometer. To encourage the efficient use of ALMA data not only by the proposers of observations but also by other researchers, we need to provide processed data instead of raw data and make it available in the archives.

— Certainly, processed data can be handled more easily by other researchers.

Nagai: Since an enormous amount of money has been invested in ALMA, it is important to promote efficient and extensive use of obtained data by many researchers. If observation data together with image data is publicly available in the archives, researchers can start their work easily. I think ALMA’s fundamental policy is to encourage the use of valuable ALMA data by a wide range of people so that more and more great scientific results will be produced.

Credit:NAOJ

“Calibration” of Observation Data”

— Could you explain the actual data processing in more detail?

Nagai: First, we need to “calibrate” the data. Calibration means data correction. Imagine we have radio data received by Antenna A and another radio data received by Antenna B which is remotely located. When the two waves are synthesized, we can have “interference” of the waves in technical terms. We need to synthesize the two waves detected precisely at the same time with each antenna, but if the sky above Antenna B is cloudy, there will be a slight delay in the arriving time of the radio wave that travels through water vapor in the air. Part of our calibration work is to calculate the difference of arriving time and perform data correction.

— How do you know the conditions where radio waves travel though clouds?

Nagai: We have various methods. For example, we use an instrument called “water vapor radiometer” installed in each antenna. The water vapor radiometer is designed to measure the amount of water vapor in the sky. We can calibrate the delay of radio waves using this data. Another method is to calculate the delay of radio waves from the results of actual observations of bright radio sources in the sky. If we have a delay, the obtained image of the object becomes blurry. Then, we conduct actual observations of an object that only looks like a point source and based on the obtained image, we correct blur.

When there are clouds of water vapor in the sky, they block the paths of radio waves and cause delays. It results in distortion of a produced image because of failed synthesis of radio waves received by multiple antennas. Credit: NAOJ

— What else will be done by calibration other than studying the delay of radio waves?

Nagai: We also perform calibration of radio intensity. It is not so easy to determine the intensity of radio waves emitted from astronomical objects. Because, ALMA has an extremely large and complicated system. The recorded signal passes all the way from the antenna, receiver, digital backend, optical fiber, to the correlator. But what astronomers want to know is how strong the radio emission was before entering the telescope. So, when we detect different intensity of radio wave in different epochs, we need to figure out whether the radio intensity of the object has really changed or it is affected by weather or instrument conditions of the telescope.

— How can you identify the cause?

Nagai: We use certain astronomical objects, whose radio intensities have already been known, as standard “calibration sources” for reference. Based on the reference value, we calibrate the radio intensity of the target object afterwards.

“How to Decide the Colors of Astronomical Images?”

— After calibrating the data received by ALMA, images will be created.

Nagai: Right. Imaging is also carried out by our team.

— You said that radio waves are invisible to the human eye and we don’t know what color the emission really is. But, we see colorful images in press releases. How do you color images?

Nagai: To tell the truth, we have no specific rules in coloring. There is a standard color allocation method provided by image visualization software, and we follow that method in principle.

— I see. Does the standard method use red colors for longer wavelengths and blue colors for shorter wavelengths as we can see with the naked eye?

Nagai: We rarely allocate colors according to the wavelength. What we often use is “rainbow color” which is applied not according to the wavelengths but the radio intensity. As the intensity increases, the color becomes more reddish and as it decreases, the color becomes more purplish.

— Are you saying that researchers don’t care about what colors are used for imaging?

Nagai: Not much. They are more interested in the difference of radio intensity. So, we often use rainbow color so as to show the difference of radio intensity more clearly, instead of trying to make it look beautiful, even though we have no limitations set by the data format in choosing colors for images created by the analysis team.

— Do you use different color allocation methods in creating images for press releases to be released to the public?

Nagai: Yes, we do care more about creating visually appealing images for press releases.

HL Tauri, observed with ALMA, shown with different colors. A variety of color allocation methods are available depending on the purpose of use and the points to be emphasized.
Credit: ALMA (ESO/NAOJ/NRAO)

“Automatic Analysis System “Pipeline” Newly Introduced”

— Do you perform calibration and imaging manually by each observation?

Nagai: Actually, we have a system called “Pipeline” to automatically perform calibration and imaging.

— Is that a name of software?

Nagai: Maybe more appropriate to say it is a “system” rather than software. We named it “Pipeline” because it automatically performs a series of processing from calibration to imaging just by feeding raw data. However, it didn’t work well initially and involved a lot of manual works. We had to keep proposers waiting long until they received their observation data

— You must have had a hard time.

Nagai: Yes, it was very hard at the beginning, but there was a dramatic improvement over the last year. As the development of Pipeline has progressed, we have less and less errors. The amount of our manual work was reduced substantially.

— Is analysis work carried out by each region?

Nagai: Yes, analysis work has been conducted separately in Chile, East Asia, North America, and Europe.

“With Pride in Working for the World’s leading Telescope”

— I guess you have difficulties in your data analysis work, but what is the fascinating part about your work?

Nagai: ALMA is the world’s leading telescope that has been producing more and more new scientific results and making amazing discoveries in exploration of mysteries of the universe. As a staff member of ALMA, I feel it very important to make efforts every day to ensure the delivery of high-quality data to the public. So, I am glad that I can contribute to the data analysis work, which is very rewarding. As data analysis requires profound knowledge of the radio interferometer, we are all proud of making professional contributions to this important work as members of the East Asian ALMA Regional Center.

— You are working with the spirit of professionalism.

Nagai: Also, through data analysis work, I get to know more people. ALMA users include a wide range of researchers from various fields of study. I used to work mostly with people of the same field, now I have more opportunities to be connected with researchers who have totally different expertise. And I have more contact with researchers of other fields in answering questions about data analysis and such contact sometimes leads to collaborative research. I enjoy these kinds of exchanges with new people very much.

— We heard your specialty is study of black holes.

Nagai: Yes. I specialized in radio observation of jets in supermassive black holes.

— As a researcher, would you like to get back to your research when all the data analysis works were transferred to Chile?

Nagai: Researchers are wishing to keep doing research, so I dream about devoting 100% of my time and energy to my research. However, considering the importance of large-scale astronomical projects like ALMA for the advancement of astronomy, I understand specialized manpower will be continuously needed. So, taking the advantage of my experience with ALMA, I would like to utilize what I have learnt so far for the development of astronomy. I think it would be great if I could achieve a good balance between my project work and research and make even small portion of time for my research.

Hiroshi Nagai (Project Associate Professor at the NAOJ Chile Observatory)
Obtained Ph.D. in SOKENDAI (the Graduate University for Advanced Studies) in 2007. Specialized in observational study of the circumference of supermassive black holes at the galactic centers and high-speed gas flows (jets) emanating from supermassive black holes. After obtained Ph.D, engaged in researches at the National Astronomical Observatory of Japan (NAOJ) and Japan Aerospace Exploration Agency (JAXA) and then joined the NAOJ ALMA project in 2011. Made great contributions to performance verification of polarization observation with ALMA and received the 2017 NAOJ Director’s Award. From 2014 to 2017, played a leading role in the East Asian ALMA Data Analysis Team and supporting the production of various scientific results in collaboration with other team members. From 2017 October, serving as the interim manager of East-Asia ALMA Regional Center who coordinates the ALMA science operation activity and user support in East-Asia region.

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.

From ALMA: “Fierce Winds Quench Wildfire-like Starbirth in Far-flung Galaxy”

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

From ALMA

6 September, 2018

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

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

ALMA, aided by a gravitational lens, imaged the outflow, or “wind”, from a galaxy seen when the universe was only one billion years old. The ALMA image (circle call out) shows the hydroxyl (OH) molecules. These molecules trace the location of star-forming gas as it is fleeing the galaxy, driven by a supernova or black-hole powered “wind.” The background star field (Blanco Telescope Dark Energy Survey) shows the location of the galaxy. The circular, double-lobe shape of the distant galaxy is due to the distortion caused by cosmic magnifying effect of an intervening galaxy. Credit: ALMA (ESO/NAOJ/NRAO), Spilker; NRAO/AUI/NSF, S. Dagnello; AURA/NSF

Dark Energy Survey

Dark Energy Camera [DECam], built at FNAL

NOAO/CTIO Victor M Blanco 4m Telescope which houses the DECam at Cerro Tololo, Chile, housing DECam at an altitude of 7200 feet

Astronomers using ALMA, with the aid of a gravitational lens, have detected the most-distant galactic “wind” of molecules ever observed, seen when the universe was only one billion years old. By tracing the outflow of hydroxyl (OH) molecules, which herald the presence of star-forming gas in galaxies, the researchers show how some galaxies in the early universe quenched an ongoing wildfire of starbirth.

Some galaxies, like the Milky Way and Andromeda, have relatively slow and measured rates of starbirth, with about one new star igniting each year. Other galaxies, known as starburst galaxies, forge 100s or even 1000s of stars each year. This furious pace, however, cannot be maintained indefinitely.

Milky Way NASA/JPL-Caltech /ESO R. Hurt

Andromeda Galaxy Adam Evans

To avoid burning out in a short-lived blaze of glory, some galaxies throttle back their runaway starbirth by ejecting, at least temporarily, vast stores of gas into their expansive halos, where the gas either escapes entirely or slowly rains back in on the galaxy, triggering future bursts of star formation.

Up to now, however, astronomers have been unable to directly observe these powerful outflows in the very early universe, where such mechanisms are essential to prevent galaxies from growing too big, too fast.

New observations with the Atacama Large Millimeter/submillimeter Array (ALMA), show, for the first time,a powerfulgalactic “wind” of molecules in a galaxy seen when the universe was only one billion years old. This result provides insights into how certain galaxies in the early universe were able to self-regulate their growth,so they could continue forming stars across cosmic time.

“Galaxies are complicated, messy beasts, and we think outflows and winds are critical pieces to how they form and evolve, regulating their ability to grow,” said Justin Spilker, an astronomer at the University of Texas at Austin and lead author on a paper appearing in the journal Science.

Astronomers have observed winds with the same size, speed, and mass in nearby starbursting galaxies, but the new ALMA observation is the most distant unambiguous outflow ever seen in the early universe.

The galaxy, known as SPT2319-55, is more than 12 billion light-years away. It was discovered by the National Science Foundation’s South Pole Telescope.

South Pole Telescope SPTPOL. The SPT collaboration is made up of over a dozen (mostly North American) institutions, including the University of Chicago, the University of California, Berkeley, Case Western Reserve University, Harvard/Smithsonian Astrophysical Observatory, the University of Colorado Boulder, McGill University, The University of Illinois at Urbana-Champaign, University of California, Davis, Ludwig Maximilian University of Munich, Argonne National Laboratory, and the National Institute for Standards and Technology. It is funded by the National Science Foundation.

ALMA was able to observe this object at such tremendous distance with the aid of a gravitational lens provided by a different galaxy that sits almost exactlyalong the line of sight between Earth and SPT2319-55. Gravitational lensing – the bending of light due to gravity — magnifies the background galaxy to make it appear brighter, which allows the astronomers to observe it in more detail than they would otherwise be able to.

Radio galaxies gravitationally lensed by a very large foreground galaxy cluster Hubble

Astronomers use specialized computer programs to “unscramble” the effects of gravitational lensing to reconstruct an accurate image of the more-distant object.

This lens-aided view revealed a powerful“wind” of star-forming gas exiting the galaxy at nearly 800 kilometers per second. Rather than a constant, gentle breeze, the wind is hurtling away in discrete clumps, removing the star-forming gas just as quickly as the galaxy can turn that gas into new stars.

The outflow was detected by the millimeter-wavelength signature of a molecule called hydroxyl (OH), which appeared as an absorption line: essentially, the shadow of an OH fingerprint in the galaxy’s bright infrared light.

As new, dust-enshrouded stars form, that dust heats up and glows brightly in infrared light. However, the galaxy is also launching a wind, and some of it is blowing in our direction. As the infrared light passes through the wind on its journey toward Earth, the OH molecules in the wind absorb some of the infrared light at a very particular wavelength that ALMA can observe.

“That’s the absorption signature that we detected, and from that, we can also tell how fast the wind is moving and get a rough idea of how much material is contained in the outflow,” said Spilker. ALMA can detect this infrared light because it has been stretched to millimeter wavelengths on its journey to Earth by the ongoing expansion of the Universe.

Molecular winds are an efficient way for galaxies to self-regulate their growth, the researchers note. These winds are likely triggered by either the combined effectof all the supernova explosions that go along with rapid, massive star formation or by a powerful release of energy as some of the gas in the galaxy falls down onto the supermassive black hole at its center.

“So far, we have only observed one galaxy at such a remarkable cosmic distance, but we’d like to know if winds like these are also present in other galaxies to see just how common they are,” concluded Spilker. “If they occur in basically every galaxy, we know that molecular winds are both ubiquitous and also a prevalent way for galaxies to self-regulate their growth.”

“This ALMA observation demonstrates how nature coupled with exquisite technology can give us insights into distant astronomical objects,” said Joe Pesce, NSF Program Director for NRAO/ALMA, “and the frequency range accessible to ALMA meant it was able to the detect the redshifted spectral feature from this important molecule.”

Artist impression of an outflow of molecular gas from an active star-forming galaxy. Credit: NRAO/AUI/NSF, D. Berry

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)

This research is presented in a paper titled Fast Molecular Outflow from a Dusty Star-Forming Galaxy in the Early Universe, by J.S. Spilker et al. in the journal Science and Science

The research team was composed by J. S. Spilker [1,2,∗],M. Aravena [3], M. Béthermin [4], S. C. Chapman [5], C.-C. Chen [6], D. J. M. Cunningham [5,7], C. De Breuck [6], C. Dong [8], A. H. Gonzalez [8], C. C. Hayward [9,10], Y. D. Hezaveh [11], K. C. Litke [2], J. Ma [12], M. Malkan [13], D. P. Marrone [2], T. B. Miller [5,14], W. R. Morningstar [11], D. Narayanan [8], K. A. Phadke [15], J. Sreevani [15], A. A. Stark [10], J. D. Vieira [15], A. Weiß [16].

[1] Department of Astronomy, University of Texas at Austin, 2515 Speedway Stop C1400, Austin, TX 78712, USA.

[2] Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721, USA.

[3] Núcleo de Astronomía, Facultad de Ingeniería, Universidad Diego Portales, Av. Ejército 441, Santiago, Chile.

[4] Aix-Marseille Univ., Centre National de la Recherche Scientifique, Laboratoire d’Astrophysique de Marseille, Marseille, France.

[5] Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia, Canada.

[6] European Southern Observatory, Karl Schwarzschild Straße 2, 85748 Garching, Germany.

[7] Department of Astronomy and Physics, Saint Mary’s University, Halifax, Nova Scotia, Canada.

[8] Department of Astronomy, University of Florida, Bryant Space Sciences Center, Gainesville, FL 32611, USA.

[9] Center for Computational Astrophysics, Flatiron Institute, 162 Fifth Avenue, New York, NY 10010, USA.

[10] Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA.

[11] Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, Stanford, CA 94305, USA.

[12] Department of Physics and Astronomy, University of California, Irvine, CA 92697, USA

[13] Department of Physics and Astronomy, University of California, Los Angeles, CA 90095, USA.

[14] Department of Astronomy, Yale University, 52 Hillhouse Avenue, New Haven, CT 06511, USA.

[15] Department of Astronomy, University of Illinois, 1002 West Green St., Urbana, IL 61801, USA.

[16] Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69 D-53121 Bonn, Germany.

∗Corresponding author. E-mail: spilkerj@gmail.com.

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.