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.

See the full article here .

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Please help promote STEM in your local schools.

Stem Education Coalition

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

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

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From ALMA: “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 .

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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: “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.

From ALMA: “Precise Record of Baby-Stars’ Growth on Millimeter Wavelength”

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

From ALMA

31 August, 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 – Japan
Phone: +81 422 34 3630
Email: hiramatsu.masaaki@nao.ac.jp

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

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

Babies grow up fast in the blink of an eye, and thus, their parents wish to record their growth without missing any moment; This is true not only for human babies but also for baby-stars, called protostars, although the recorders are not parents but astronomers in this case. Protostars’ age, or evolutionary stages, has been determined from observations at near and mid-infrared wavelengths. The youngest stage, called Class 0, is defined by non-detection at near and mid-infrared wavelengths, corresponding to <300,000 years old. This definition cannot differentiate younger from older Class 0 protostars. Furthermore, astronomers expect from studies on even older protostars that protostars grow up faster at earlier stages than at later stages, as human babies do, implying that they miss many precious moments of their growth.

The background image shows the Serpens Main star-forming cluster in the near infrared. The inset image shows the location of the two Class 0 protostars SMM4A and SMM4B in the entire group, in 1.3 mm wavelength. Credit: ESO/ALMA(ESO/NAOJ/NRAO)/Aso et al.

As we all know, human “babies” (fetuses) in mothers’ wombs also grow at a fast rate – just as the star babies do. Using ultrasound scanning techniques, parents can hear the baby’s heart beating during the regular prenatal examinations; not only so, but they could also even detect how much the thigh bone grows, how much the head circumference is, or perhaps, getting some hints about “girl or boy?”! All of these are essential indicators informing us about how much progress our babies are making concerning growth.

Similarly, to record the critical evolutionary stages of baby stars, rather than ultrasound scanners, astronomers would use millimeter/ sub-millimeter telescopes. To probe the fast growth of Class 0 protostars, an international team led by Dr. Yusuke Aso of Academia Sinica Institute of Astronomy and Astrophysics (ASIAA, Taiwan) has observed three Class 0 protostars using the Atacama Large Millimeter/submillimeter Array (ALMA) and has differentiated evolutionary stages of these protostars in multiple aspects. Thanks to ALMA’s strong capabilities, the team revealed four evolutionary indicators in details: (1) dusty disk growth on 100 astronomical-unit scales, (2) widening of outflow opening angles, (3) carbon monoxide (CO) desorption from icy grains due to temperature rising, and (4) weakening of accretion shock, all of which are consistent with theoretical predictions for young protostars.

Their work demonstrates the importance of millimeter wavelength on probing young protostars’evolution. The work was also accomplished by ALMA’s high spatial resolution differentiating morphology on a small scale and its high sensitivity detecting the faint molecular line from the cold regions. The lead author Dr. Aso says: “From now on, the precious moments of young baby-stars’ fast growth will be recorded more precisely on millimeter wavelength.”

Additional Information
This research was presented in a paper The Distinct Evolutionary Nature of Two Class 0 Protostars in Serpens Main SMM4 by Aso et al. to appear in The Astrophysical Journal.

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 Observed an Unstoppable Monster in the Early Universe”

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

From ALMA

29 August, 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 – Japan
Phone: +81 422 34 3630
Email: hiramatsu.masaaki@nao.ac.jp

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

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

Astronomers obtained the most detailed anatomy chart of a monster galaxy located 12.4 billion light-years away. Using the Atacama Large Millimeter/submillimeter Array (ALMA), the team revealed that the molecular clouds in the galaxy are highly unstable, which leads to runaway star formation. Monster galaxies are thought to be the ancestors of the huge elliptical galaxies in today’s Universe; therefore, these findings pave the way to understand the formation and evolution of such galaxies.

“One of the best parts of ALMA observations is to see the far-away galaxies with unprecedented resolution,” says Ken-ichi Tadaki, a postdoctoral researcher at the Japan Society for the Promotion of Science and the National Astronomical Observatory of Japan, lead author of the research paper published in the journal Nature.

Monster galaxies, or starburst galaxies, form stars at a startling pace; 1000 times higher than the star formation rate in our Galaxy. However, why are they so active? To tackle this problem, researchers need to know the environment around the stellar nurseries. Drawing detailed maps of molecular clouds is one crucial step to scout these cosmic monsters.

Tadaki and the team targeted a chimerical galaxy COSMOS-AzTEC-1. This galaxy was first discovered with the James Clerk Maxwell Telescope in Hawai`i, and later the Large Millimeter Telescope (LMT) in Mexico found an enormous amount of carbon monoxide gas in the galaxy and revealed its hidden starburst. The LMT observations also measured the distance to the galaxy, and found that it is 12.4 billion light-years [1].

East Asia Observatory James Clerk Maxwell Telescope, Mauna Kea, Hawaii, USA,4,207 m (13,802 ft) above sea level

The University of Massachusetts Amherst and Mexico’s Instituto Nacional de Astrofísica, Óptica y Electrónica
Large Millimeter Telescope Alfonso Serrano, Mexico, at an altitude of 4850 meters on top of the Sierra Negra

Researchers have found that COSMOS-AzTEC-1 is rich with the ingredients of stars, but it was still difficult to figure out the nature of the cosmic gas in the galaxy. The team utilized the high resolution and high sensitivity of ALMA to observe this monster galaxy and obtain a detailed map of the distribution and the motion of the gas. Thanks to the most extended ALMA antenna configuration of 16 km, this is it the highest resolution molecular gas map of a distant monster galaxy.

“We found that there are two distinct large clouds several thousand light years away from the center,” explains Tadaki. “In most distant starburst galaxies, stars are actively formed in the center. So, it is surprising to find off-center clouds.”

Artist’s impression of the monster galaxy COSMOS-AzTEC-1. This galaxy is located 12.4 billion light-years away and is forming stars 1000 times more rapidly than our Milky Way Galaxy. ALMA observations revealed dense gas concentrations in the disk and intense stars formation in those concentrations. Credit: National Astronomical Observatory of Japan.

The astronomers further investigated the nature of the gas in COSMOS-AzTEC-1 and found that the clouds throughout the galaxy are very unstable, which is unusual. In a typical situation, the inward gravity and outward pressure are balanced in the clouds. Once gravity overcomes pressure, the gas cloud collapses and forms stars at a rapid pace. Then, stars and supernova explosions at the end of the stellar life cycle blast out gases, which increases the outward pressure. As a result, gravity and pressure reach a balanced state and star formation continues at a moderate pace. In this way star formation in galaxies is self-regulating. However, in COSMOS-AzTEC-1, the pressure is far weaker than the gravity and hard to balance. Therefore, this galaxy shows runaway star formation and morphed into an unstoppable monster galaxy.

The team estimated that the gas in COSMOS-AzTEC-1 will be completely consumed in 100 million years, which is ten times faster than in other star-forming galaxies.

However, why is the gas in COSMOS-AzTEC-1 so unstable? Researchers do not have a definitive answer yet, but galaxy merger is a possible cause. Galaxy collision may have efficiently transported the gas into a small area and ignited intense star formation.

“At this moment, we have no evidence of merger in this galaxy. By observing other similar galaxies with ALMA, we want to unveil the relation between galaxy mergers and monster galaxies,” summarizes Tadaki.
Notes

[1] The measured redshift of COSMOS-AzTEC-1 is z=4.3. A calculation based on the latest cosmological parameters measured with Planck (H0=67.3 km/s/Mpc, Ωm=0.315, Λ=0.685: Planck 2013 Results) yields the distance of 12.4 billion light-years. Please refer to “Expressing the distance to remote objects” for the details.
Additional Information

These observation results appear as Tadaki et al. “The gravitationally unstable gas disk of a starburst galaxy 12 billion years ago” in Nature on August 30, 2018.

The research team members are:

Ken-ichi Tadaki (Japan Society for the Promotion of Science / National Astronomical Observatory of Japan), Daisuke Iono (National Astronomical Observatory of Japan / SOKENDAI), Min S. Yun (University of Massachusetts), Itziar Aretxaga (Instituto Nacional de Astrofísica, Óptica y Electrónica), Bunyo Hatsukade (The University of Tokyo), David H. Hughes (Instituto Nacional de Astrofísica, Óptica y Electrónica), So Ikarashi (University of Groningen), Takuma Izumi (National Astronomical Observatory of Japan), Ryohei Kawabe (National Astronomical Observatory of Japan), Kotaro Kohno (The University of Tokyo), Munju Lee (Nagoya University), Yuichi Matsuda (National Astronomical Observatory of Japan / SOKENDAI), Kohichiro Nakanishi (National Astronomical Observatory of Japan / SOKENDAI), Toshiki Saito (Max Planck Institute for Astronomy), Yoichi Tamura (Nagoya University), Junko Ueda (National Astronomical Observatory of Japan), Hideki Umehata (RIKEN), Grant W. Wilson (University of Massachusetts), Tomonari Michiyama (SOKENDAI), Misaki Ando (SOKENDAI), Patrick Kamieneski (University of Massachusetts).

This research was supported by JSPS KAKENHI (Grant Number 17J04449).

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: “First Science with ALMA’s Highest-Frequency Capabilities”

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

From ALMA

17 August, 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

Illustration highlighting ALMA’s high-frequency observing capabilities. Credit: NRAO/AUI/NSF, S. Dagnello

A team of scientists using the highest-frequency capabilities of the Atacama Large Millimeter/submillimeter Array (ALMA) has uncovered jets of warm water vapor streaming away from a newly forming star. The researchers also detected the “fingerprints” of an astonishing assortment of molecules near this stellar nursery.

The ALMA telescope in Chile has transformed how we see the universe, showing us otherwise invisible parts of the cosmos. This array of incredibly precise antennas studies a comparatively high-frequency sliver of radio light: waves that range from a few tenths of a millimeter to several millimeters in length. Recently, scientists pushed ALMA to its limits, harnessing the array’s highest-frequency (shortest wavelength) capabilities, which peer into a part of the electromagnetic spectrum that straddles the line between infrared light and radio waves.

“High-frequency radio observations like these 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 appearing 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.”

Under ideal atmospheric conditions, which occurred on the evening of 5 April 2018, astronomers trained ALMA’s highest-frequency, submillimeter vision on a curious region of the Cat’s Paw Nebula (also known as NGC 6334I), a star-forming complex located about 4,300 light-years from Earth in the direction of the southern constellation Scorpius.

Previous ALMA observations of this region at lower frequencies uncovered turbulent star formation, a highly dynamic environment, and a wealth of molecules inside the nebula.

To observe at higher frequencies, the ALMA antennas are designed to accommodate a series of “bands” — numbered 1 to 10 — that each study a particular sliver of the spectrum. The Band 10 receivers observe at the highest frequency (shortest wavelengths) of any of the ALMA instruments, covering wavelengths from 0.3 to 0.4 millimeters (787 to 950 gigahertz), which is also considered to be long-wavelength infrared light.

These first-of-their-kind ALMA observations with Band 10 produced two exciting results.

Pictured here is one of the cold cartridge assemblies of the Band 10 receiver, which gives ALMA its highest-frequency capabilities. Credit: ALMA (ESO/NAOJ/NRAO)

The upper blue portion of this graph shows the spectral lines ALMA detected in a star-forming region of the Cat’s Paw Nebula. The lower black portion shows the lines detected by the European Space Agency’s Herschel Space Observatory.

ESA/Herschel spacecraft active from 2009 to 2013

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: NRAO/AUI/NSF, B. McGuire et al.

Jets of Steam from Protostar

One of ALMA’s first Band 10 results was also one of the most challenging, the direct observation of jets of water vapor streaming away from one of the massive protostars in the region. ALMA was able to detect the submillimeter-wavelength light 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 nucleus).

“Normally, we wouldn’t be able to directly see this particular signal at all from the ground,” said Crystal Brogan, an astronomer at the NRAO and co-author on the paper. “Earth’s atmosphere, even at remarkably arid places, still contains enough of water vapor to completely overwhelm this signal from any cosmic source. During exceptionally pristine conditions in the high Atacama Desert, however, ALMA can in fact detect that signal. This is something no other telescope on Earth can achieve.”

As stars begin 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.

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

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.

These observations also show that in the regions where this water is slamming into the surrounding gas, low-frequency water masers – naturally occurring microwave versions of lasers — flare up. The masers were detected in complementary observations by the National Science Foundation’s Very Large Array.

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

ALMA Band 10 image of heavy water (HDO) streaming away from NGC 6334I in the Cat’s Paw Nebula. This image is the result of ALMA’s highest-frequency observing capabilities, which push the limits of ground-based astronomy. Credit: ALMA (ESO/NAOJ/NRAO); NRAO/AUI/NSF, B. Saxton

ALMA Observes Molecules Galore

In addition to making striking images of objects in space, ALMA is also a supremely sensitive cosmic chemical sensor. As molecules tumble and vibrate in space, they naturally emit light at specific wavelengths, which appear as spikes and dips on a spectrum. All of ALMA’s receiver bands can detect these unique spectral fingerprints, but those lines at the highest frequencies offer unique insight into lighter, important chemicals, like heavy water. They also provide the ability to see signals from complex, warm molecules, which have weaker spectral lines at lower frequencies.

Using Band 10, the researchers were able to observe a region of the spectrum that is extraordinarily rich in molecular fingerprints, including glycoaldehyde, the simplest sugar-related molecule.

When compared to previous best-in-the-world observations of the same source with the European Space Agency’s Herschel Space Observatory, the ALMA observations detected more than ten times as many spectral lines.

“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.”

ALMA is able to take advantage of these rare windows of opportunity when the atmospheric conditions are “just right” by using dynamic scheduling. That means, the telescope operators and astronomers carefully monitor the weather and conduct those planned observations that best fit the prevailing conditions.

“There certainly are quite a few conditions that have to be met to conduct a successful observation using Band 10,” concluded Brogan. “But these new ALMA results demonstrate just how important these observations can be.”

“To remain at the forefront of discovery, observatories must continuously innovate to drive the leading edge of what astronomy can accomplish,” said Joe Pesce, the program director for the National Radio Astronomy Observatory at NSF. “That is a core element of NSF’s NRAO, and its ALMA telescope, and this discovery pushes the limit of what is possible through ground-based astronomy.”

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: “Pair of Colliding Stars Spill Radioactive Molecules into Space”

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

From ALMA

30 July, 2018

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

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

Richard Hook
Public Information Officer, ESO
Garching bei München, Germany
Phone: +49 89 3200 6655
Cell phone: +49 151 1537 3591
Email: rhook@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

Composite image of CK Vul, the remains of a double-star collision. This impact launched radioactive molecules into space, as seen in the orange double-lobe structure at the center. This is an ALMA image of 27-aluminum monofluoride, but the rare isotopic version of AlF resides in the same region. The red, diffuse image is an ALMA image of the more extended dust in the region. The blue is optical hydrogen emission from the Gemini observatory. Credit: ALMA (ESO/NAOJ/NRAO), T. Kamiński & M. Hajduk; Gemini, NOAO/AURA/NSF; NRAO/AUI/NSF, B. Saxton

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

Astronomers have made the first definitive detection of a radioactive molecule in interstellar space: a form, or isotopologue of aluminum monofloride (26AlF). The new data – made with ALMA and the NOEMA radio telescopes – reveal that this radioactive isotopologue was created by the collision of two stars, a tremendously rare cosmic event that was witnessed on Earth as a “new star,” or nova, in the year 1670.

IRAM NOEMA interferometer, Located in the French Alpes on the wide and isolated Plateau de Bure at an elevation of 2550 meters

When two Sun-like stars collide, the result can be a spectacular explosion and the formation of an entirely new star. One such event was seen from Earth in 1670. It appeared to observers as a bright, red “new star.” Though initially visible with the naked eye, this burst of cosmic light quickly faded and now requires powerful telescopes to see the remains of this merger: a dim central star surrounded by a halo of glowing material flowing away from it.

Approximately 348 years after this event, an international team of astronomers using ALMA and the NOEMA radio telescopes studied the remains of this explosive stellar merger — known as CK Vulpeculae (CK Vul) — and discovered the clear and convincing signature of a radioactive version of aluminum (26Al, an atom with 13 protons and 13 neutron) bound with atoms of fluorine, forming 26-aluminum monofluoride (26AlF).

This picture shows the remains of the new star that was seen in the year 1670. It was created from a combination of visible-light images from the Gemini telescope (blue), a submillimetre map showing the dust from the SMA (green) and finally a map of the molecular emission from APEX and the SMA (red).

CfA Submillimeter Array Mauna Kea, Hawaii, USA, Altitude 4,080 m (13,390 ft)

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

The star that European astronomers saw in 1670 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.
Date 23 March 2015,
Source http://www.eso.org/public/poland/images/eso1511b/
Author ESO/T. Kamiński

This is the first molecule bearing an unstable radioisotope definitively detected outside of our solar system. Unstable isotopes have an excess of nuclear energy and eventually decay into a stable, less-radioactive form. In this case, the 26-aluminum (26Al) decays to 25-magnesium (25Mg).

“The first solid detection of this kind of radioactive molecule is an important milestone in our exploration of the cool molecular universe,” said Tomasz Kamiński, an astronomer with the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., and lead author on a paper appearing in Nature Astronomy.

The researchers detected the unique spectral signature of these molecules in the debris surrounding CK Vul, which is approximately 2,000 light-years from Earth. As these molecules spin and tumble through space, they emit a distinctive fingerprint of millimeter-wavelength light, a process known as “rotational transition.” Astronomers consider this the “gold standard” for molecular detections.

The characteristic molecular fingerprints are usually taken from laboratory experiments. In the case of 26AlF, this method is not applicable because 26-aluminum is not present on Earth. Laboratory astrophysicists from the University of Kassel/Germany therefore used the fingerprint data of stable and abundant 27AlF molecules to derive accurate data for the rare 26AlF molecule. “This method of extrapolation is based on the so-called Dunham approach,” explained Alexander Breier from the Kassel team. “It allows researchers to precisely calculate the rotational transitions of 26AlF with an accuracy far beyond the needs of astronomical observers.”

The observation of this particular isotopologue provides fresh insights into the merger process that created CK Vul. It also demonstrates that the deep dense inner layers of a star, where heavy elements and radioactive isotopes are forged, can be churned up and cast into space by stellar collisions. “We are observing the guts of a star torn apart three centuries ago by a collision,” observed Kamiński. “How cool is that?”

Artist impression of the collision of two stars, like the ones that formed CK Vul. The inset illustrates the inner structure of one red giant before the merger. A thin layer of 26-aluminum (brown) surrounds a helium core. An extended convective envelope (not to scale), which forms the outermost layer of the star, can mix material from inside the star to the surface, but it never reaches deep enough to dredge 26-aluminum up to the surface. Only a collision with another star can disperse 26-aluminum. Credit: NRAO/AUI/NSF; S. Dagnello

The astronomers also determined that the two stars that merged were relatively low-mass, with one being a red giant star with a mass somewhere between 0.8 and 2.5 times that of our Sun.

“This first direct observation of this isotope in a stellar-like object is also important in the broader context of the galactic chemical evolution,” noted Kamiński. “This is the first time an active producer of the radioactive nuclide 26Al has been directly observationally identified.”

It has been known for decades that there is about three entire Suns’ worth of 26Al spread across the Milky Way. But these observations, made at gamma-ray wavelengths, could only identify that the signal was there; they couldn’t pinpoint individual sources and it was unclear how the isotopes got there.

With current estimates on the mass of 26Al in CK Vul (about a quarter the mass of Pluto) and the rather rare occurrence of mergers such as this, it seems rather unlikely that mergers are solely responsible for this galactic radioactive material, the astronomers conclude.

However, ALMA and NOEMA can only detect the amount of 26Al bound with fluorine. The actual mass of 26Al in CK Vul (in atomic form) may be much greater. It is also possible that other merger remnants may have far greater amounts. Astronomers may also have underestimated the current merger rates in the Milky Way. “So this is not a closed issue and the role of mergers may be non-negligible,” speculated Kamiński.

ALMA image of the radioactive molecule 26-aluminum monofluoride, as detected in CK Vul. Credit: ALMA (ESO/NAOJ/NRAO); NRAO/AUI/NSF; B. Saxton

The discovery involved the following telescopes/facilities: APEX, IRAM 30m, NOEMA, ALMA, and SMA. The most relevant observations were done with the PdBI/NOEMA interferometer and with the ALMA array, including its newly commissioned band 5 receiver.

ver.

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: “ALMA Discover Exciting Structures in a Young Protoplanetary Disk That Support Planet Formation”

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

From ALMA

20 June, 2018

Ruobing Dong
Steward Observatory, University of Arizona, USA
Institute of Astronomy and Astrophysics, Academia Sinica, Taiwan
+1 609 423 5625
rbdong@gmail.com

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

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

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

Richard Hook
Public Information Officer, ESO
Garching bei München, Germany
Phone: +49 89 3200 6655
Cell phone: +49 151 1537 3591
rhook@eso.org

ALMA image of the 0.87 mm continuum emission from the MWC 758 disk. Credit: ALMA (ESO/NAOJ/NRAO)/Dong et al.

Since early 2000, rich structures, including gaps and rings, dust clumps, and spiral arm-like features, have been discovered in a few tens of disks surrounding newborn stars. With the belief that planets are forming inside, astronomers named these disks protoplanetary disks.

The origin of these structures is in hot debate among astronomers. In one scenario, they are thought to be produced by unseen planets forming inside and gravitationally interacting with the host disks, as planets open gaps, shepherd dust clumps, and excite spiral arms.

Alternative ways to produce observed disk structures that do not invoke planets have also been raised. For examples, large central cavities may be the outcome of photoevaporation, as high energy radiations from the central star evaporate the inner disk. Also, under certain conditions shadows in disks may mimic the spiral arms seen in reflected light.

The protoplanetary disk around a young star MWC 758 is located at 500 light years from us. In 2012, a pair of near symmetric giant spiral arms was discovered in reflected light. In dust thermal and molecular gas line emission at millimeter wavelengths, a big inner hole and two major dust clumps have been found, too.

Now with the new ALMA image, the previously known cavity of MWC 758 is shown to be off-centered from the star with its shape well described by an ellipse with one focus on the star. Also, a millimeter dust emission feature corresponds nicely with one of the two spiral arms previously seen in reflected light. Both discoveries are the first among protoplanetary disks.

“MWC 758 is a rare breed!”, says Sheng-Yuan Liu at ASIAA, co-author of this study, “All major types of disk structures have been found in this system. It reveals to us one of the most comprehensive suites of evidence of planet formation in all protoplanetary disks.”

Previously in 2015, Dr. Dong and his collaborators proposed that the two arms in the MWC 758 disk can be explained as driven by a super-Jupiter planet just outside the disk.

“Our new ALMA observations lend crucial support to planet-based origins for all the structures.”, says Dr. Takayuki Muto at Kogakuin University, Japan, co-author of this research, “For example, it’s exciting to see ellipses with one focus on the star. That’s Kepler’s first law! It’s pointing to a dynamical origin, possibly interacting with planets.”

The off-centered cavity strongly, on the other hand, disfavors alternative explanations such as photoevaporation, which does not have an azimuthal dependence.

Various disk structures are marked. The green dotted contours mark the boundaries of the disk; the small circle at the center roughly marks the location of the star; the two green solid contours represent the extent of the two bright clumps; the solid, dotted and dashed white arcs trace out the inner, middle, and outer rings, respectively; and the arrow points out the spiral arm. The resolution (beam size, ~6.5 AU) of the image is labeled at the lower left corner. Credit: ALMA (ESO/NAOJ/NRAO)/Dong et al.

The fact that the south spiral branch is present in the millimeter emission tracing the dust rules that it’s a density arm. Other scenarios, such as shadows, which view the spiral arms as surface features, are not expected to reproduce the observations. The ultra-high resolution achieved in the new ALMA dataset also enables the detection of a slight offset between the arm locations in reflected light and in dust emission, which is consistent with models of planet-induced density wave.

“These fantastic new details are only made possible thanks to the amazing angular resolution delivered by ALMA”, says co-author Eiji Akiyama at Hokkaido University, Japan, “We took full advantage of ALMA’s long baseline capabilities, and now the MWC 758 disk joins the elite club of ultra-high-resolution ALMA disks alongside only a handful of others.”

Additional information

This research was presented in a paper “The Eccentric Cavity, Triple Rings, Two-Armed Spirals, and Double Clumps of the MWC 758 Disk” by Dong et al. to appear in The Astrophysical Journal.

The team is composed of Ruobing Dong (U. of Arizona, USA; ASIAA, Taiwan), Sheng-yuan Liu (ASIAA, Taiwan), Josh Eisner (University of Arizona, USA), Sean Andrews (Harvard-Smithsonian Center for Astrophysics, USA), Jeffrey Fung (UC Berkeley, USA), Zhaohuan Zhu (UNLV, USA) Eugene Chiang (UC Berkeley, USA), Jun Hashimoto (Astrobiology Center, NINS, Japan), Hauyu Baobab Liu (European Southern Observatory, Germany), Simon Casassus (University of Chile, Chile), Thomas Esposito (UC Berkeley, USA), Yasuhiro Hasegawa (JPL/Caltech, USA), Takayuki Muto (Kogakuin University, Japan), Yaroslav Pavlyuchenkov (Russian Academy of Sciences, Russia), David Wilner (Harvard-Smithsonian Center for Astrophysics, USA), Eiji Akiyama (Hokkaido University, Japan), Motohide Tamura (The University of Tokyo; Astrobiology Center, NINS, Japan), and John Wisniewski (U. of Oklahoma, USA).

See the full article here .

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

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

From ALMA: “ALMA Discovers Trio of Infant Planets around Newborn Star”

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

From ALMA

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

13 June 2018
Christophe Pinte
Monash University
Clayton, Victoria, Australia
Tel: +61 4 90 30 24 18
Email: christophe.pinte@univ-grenoble-alpes.fr

Richard Teague
University of Michigan
Ann Arbor, Michigan, USA
Tel: +1 734 764 3440
Email: rteague@umich.edu

Calum Turner
ESO Assistant Public Information Officer
Garching bei München, Germany
Tel: +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

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

ALMA has uncovered convincing evidence that three young planets are in orbit around the infant star HD 163296. Using a novel planet-finding technique, astronomers have identified three discrete disturbances in the young star’s gas-filled disc: the strongest evidence yet that newly formed planets are in orbit there. These are considered the first planets discovered with ALMA. This image shows part of the ALMA data set at one wavelength and reveals a clear “kink” in the material, which indicates unambiguously the presence of one of the planets. Credit: ESO, ALMA (ESO/NAOJ/NRAO); Pinte et al.

Two independent teams of astronomers have used ALMA to uncover convincing evidence that three young planets are in orbit around the infant star HD 163296. Using a novel planet-finding technique, the astronomers identified three disturbances in the gas-filled disc around the young star: the strongest evidence yet that newly formed planets are in orbit there. These are considered the first planets to be discovered with ALMA.

Artist impression of protoplanets forming around a young star. Credit: NRAO/AUI/NSF; S. Dagnello

The Atacama Large Millimeter/submillimeter Array (ALMA) has transformed our understanding of protoplanetary discs — the gas- and dust-filled planet factories that encircle young stars. The rings and gaps in these discs provide intriguing circumstantial evidence for the presence of protoplanets [1]. Other phenomena, however, could also account for these tantalising features.

This wide-field image shows the surroundings of the young star HD 163296 in the rich constellation of Sagittarius (The Archer). This picture was created from the material forming part of the Digitized Sky Survey 2. HD 163296 is the bright bluish star at the center. Credit: ESO/Digitized Sky Survey 2; Acknowledgement: Davide De Martin.

But now, using a novel planet-hunting technique that identifies unusual patterns in the flow of gas within a planet-forming disc around a young star, two teams of astronomers have each confirmed distinct, telltale hallmarks of newly formed planets orbiting an infant star [2].

“Measuring the flow of gas within a protoplanetary disc gives us much more certainty that planets are present around a young star,” said Christophe Pinte of Monash University in Australia and Institut de Planétologie et d’Astrophysique de Grenoble (Université de Grenoble-Alpes/CNRS) in France, and lead author on one of the two papers. “This technique offers a promising new direction to understand how planetary systems form.”

To make their respective discoveries, each team analysed ALMA observations of HD 163296, a young star about 330 light-years from Earth in the constellation of Sagittarius (The Archer) [3]. This star is about twice the mass of the Sun but is just four million years old — just a thousandth of the age of the Sun.

“We looked at the localised, small-scale motion of gas in the star’s protoplanetary disc. This entirely new approach could uncover some of the youngest planets in our galaxy, all thanks to the high-resolution images from ALMA,” said Richard Teague, an astronomer at the University of Michigan and principal author on the other paper.

Rather than focusing on the dust within the disc, which was clearly imaged in earlier ALMA observations, the astronomers instead studied carbon monoxide (CO) gas spread throughout the disc. Molecules of CO emit a very distinctive millimetre-wavelength light that ALMA can observe in great detail. Subtle changes in the wavelength of this light due to the Doppler effect reveal the motions of the gas in the disc.

The gaps between the rings are likely due to a depletion of dust and in the middle and outer gaps astronomers also found a lower level of gas. The depletion of both dust and gas suggests the presence of newly formed planets, each around the mass of Saturn, carving out these gaps on their brand new orbits. Credit: ESO, ALMA (ESO/NAOJ/NRAO); A. Isella; B. Saxton (NRAO/AUI/NSF).

The team led by Teague identified two planets located approximately 12 billion and 21 billion kilometres from the star. The other team, led by Pinte, identified a planet at about 39 billion kilometres from the star [4].

The two teams used variations on the same technique, which looks for anomalies in the flow of gas — as evidenced by the shifting wavelengths of the CO emission — that indicate the gas is interacting with a massive object [5].

The technique used by Teague, which derived averaged variations in the flow of the gas as small as a few percent, revealed the impact of multiple planets on the gas motions nearer to the star. The technique used by Pinte, which more directly measured the flow of the gas, is better suited to studying the outer portion of the disc. It allowed the authors to more accurately locate the third planet, but is restricted to larger deviations of the flow, greater than about 10%.

In both cases, the researchers identified areas where the flow of the gas did not match its surroundings — a bit like eddies around a rock in a river. By carefully analysing this motion, they could clearly see the influence of planetary bodies similar in mass to Jupiter.

This new technique allows astronomers to more precisely estimate protoplanetary masses and is less likely to produce false positives. “We are now bringing ALMA front and centre into the realm of planet detection,” said coauthor Ted Bergin of the University of Michigan.

Both teams will continue refining this method and will apply it to other discs, where they hope to better understand how atmospheres are formed and which elements and molecules are delivered to a planet at its birth.

Zooming in on the young star HD 163296 from ALMA Observatory

Notes

[1] Although thousands of exoplanets have been discovered in the last two decades, detecting protoplanets remains at the cutting edge of science and there have been no unambiguous detections before now. The techniques currently used for finding exoplanets in fully formed planetary systems — such as measuring the wobble of a star or the dimming of starlight due to a transiting planet — do not lend themselves to detecting protoplanets.

[2] The motion of gas around a star in the absence of planets has a very simple, predictable pattern (Keplerian rotation) that is nearly impossible to alter both coherently and locally, so that only the presence of a relatively massive object can create such disturbances.

[3] ALMA’s stunning images of HD 163296 and other similar systems have revealed intriguing patterns of concentric rings and gaps within protoplanetary discs. These gaps may be evidence that protoplanets are ploughing the dust and gas away from their orbits, incorporating some of it into their own atmospheres. A previous study [Physical Review Letters] of this particular star’s disc shows that the gaps in the dust and gas overlap, suggesting that at least two planets have formed there.

These initial observations, however, merely provided circumstantial evidence and could not be used to accurately estimate the masses of the planets.

[4] These correspond to 80, 140 and 260 times the distance from the Earth to the Sun.

[5] This technique is similar to the one that led to the discovery of the planet Neptune in the nineteenth century. In that case anomalies in the motion of the planet Uranus were traced to the gravitational effect of an unknown body, which was subsequently discovered visually in 1846 and found to be the eighth planet in the Solar System.
More information

This research was presented in two papers to appear in the same edition of the Astrophysical Journal Letters. The first is entitled Kinematic evidence for an embedded protoplanet in a circumstellar disc, by C. Pinte et al. and the second A Kinematic Detection of Two Unseen Jupiter Mass Embedded Protoplanets, by R. Teague et al.

The Pinte team is composed of: C. Pinte (Monash University, Clayton, Victoria, Australia; Univ. Grenoble Alpes, CNRS, IPAG, Grenoble, France), D. J. Price (Monash University, Clayton, Victoria, Australia), F. Ménard (Univ. Grenoble Alpes, CNRS, IPAG, Grenoble, France), G. Duchêne (University of California, Berkeley California, USA; Univ. Grenoble Alpes, CNRS, IPAG, Grenoble, France), W.R.F. Dent (Joint ALMA Observatory, Santiago, Chile), T. Hill (Joint ALMA Observatory, Santiago, Chile), I. de Gregorio-Monsalvo (Joint ALMA Observatory, Santiago, Chile), A. Hales (Joint ALMA Observatory, Santiago, Chile; National Radio Astronomy Observatory, Charlottesville, Virginia, USA) and D. Mentiplay (Monash University, Clayton, Victoria, Australia).

The Teague team is composed of: Richard D. Teague (University of Michigan, Ann Arbor, Michigan, USA), Jaehan Bae (Department of Terrestrial Magnetism, Carnegie Institution for Science, Washington, DC, USA), Edwin A. Bergin (University of Michigan, Ann Arbor, Michigan, USA), Tilman Birnstiel (University Observatory, Ludwig-Maximilians-Universität München, Munich, Germany) and Daniel Foreman- Mackey (Center for Computational Astrophysics, Flatiron Institute, New York, USA).

Research paper Pinte et al. in Astrophysical Journal Letters
Research paper Teague et al. in Astrophysical Journal Letters

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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 and VLT: “Too Many Massive Stars in Starburst Galaxies, Near and Far”

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

From ALMA

and

From European Southern Observatory

4 June 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

Zhi-Yu Zhang
University of Edinburgh and ESO
Garching bei München, Germany
Tel: +49-89-3200-6910
Email: zzhang@eso.org

Fabian Schneider
Department of Physics — University of Oxford
Oxford, United Kingdom
Tel: +44-1865-283697
Email: fabian.schneider@physics.ox.ac.uk

Rob Ivison
ESO
Garching bei München, Germany
Tel: +49-89-3200-6669
Email: rob.ivison@eso.org

Mariya Lyubenova
ESO Outreach Astronomer
Garching bei München, Germany
Tel: +49 89 3200 6188
Email: mlyubeno@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

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

This artist’s impression shows a dusty galaxy in the distant Universe that is forming stars at a rate much higher than in our Milky Way. New ALMA observations have allowed scientists to lift the veil of dust and see what was previously inaccessible — that such starburst galaxies have an excess of massive stars as compared to more peaceful galaxies.
Credit: ESO/M. Kornmesser

This image shows the four distant starburst galaxies observed by ALMA. The top images depict the 13CO emission from each galaxy, while the bottom ones show their C18O emission. The ratio of these two isotopologues allowed astronomers to determine that these starburst galaxies have an excess of massive stars. Credit: ALMA (ESO/NAOJ/NRAO), Zhang et al.

Astronomers using ALMA and the VLT have discovered that starburst galaxies in both the early and the nearby Universe contain a much higher proportion of massive stars than is found in more peaceful galaxies. The video is available in 4K UHD. Credit: ESO.
Directed by: Nico Bartmann.
Editing: Nico Bartmann.
Web and technical support: Mathias André and Raquel Yumi Shida.
Written by: Stephen Molyneux and Richard Hook.
Music: written and performed by Stan Dart (www.stan-dart.com).
Footage and photos: ESO, M. Kornmesser, L. Calçada.
Executive producer: Lars Lindberg Christensen.

Astronomers using ALMA and the VLT have discovered that both starburst galaxies in the early Universe and a star-forming region in a nearby galaxy contain a much higher proportion of massive stars than is found in more peaceful galaxies. These findings challenge current ideas about how galaxies evolved, changing our understanding of cosmic star-formation history and the build up of chemical elements.

Probing the distant Universe a team of scientists, led by University of Edinburgh astronomer Zhi-Yu Zhang, used the Atacama Large Millimeter/submillimeter Array (ALMA) to investigate the proportion of massive stars in four distant gas-rich starburst galaxies [1]. These galaxies are seen when the Universe was much younger than it is now so the infant galaxies are unlikely to have undergone many previous episodes of star formation, which might otherwise have confused the results.

Zhang and his team developed a new technique — analogous to radiocarbon dating (also known as carbon-14 dating) — to measure the abundances of different types of carbon monoxide in four very distant, dust-shrouded starburst galaxies [2]. They observed the ratio of two types of carbon monoxide containing different isotopes [3].

“Carbon and oxygen isotopes have different origins”, explains Zhang. “18O is produced more in massive stars, and 13C is produced more in low- to intermediate-mass stars.” Thanks to the new technique the team was able to peer through the dust in these galaxies and assess for the first time the masses of their stars.

The mass of a star is the most important factor determining how it will evolve. Massive stars shine brilliantly and have short lives and less massive ones, such as the Sun, shine more modestly for billions of years. Knowing the proportions of stars of different masses that are formed in galaxies therefore underpins astronomers’ understanding of the formation and evolution of galaxies throughout the history of the Universe. Consequently, it gives us crucial insights about the chemical elements available to form new stars and planets and, ultimately, the number of seed black holes that may coalesce to form the supermassive black holes that we see in the centres of many galaxies.

Co-author Donatella Romano from the INAF-Astrophysics and Space Science Observatory in Bologna explains what the team found: “The ratio of 18O to 13C was about 10 times higher in these starburst galaxies in the early Universe than it is in galaxies such as the Milky Way, meaning that there is a much higher proportion of massive stars within these starburst galaxies.”

The ALMA finding is corroborated by another discovery in the local Universe. A team led by Fabian Schneider of the University of Oxford, UK, made spectroscopic measurements with ESO’s Very Large Telescope of 800 stars in the gigantic star-forming region 30 Doradus in the Large Magellanic Cloud in order to investigate the overall distribution of stellar ages and initial masses [4].

30 Doradus, The Tarantula Nebula or NGC 2070, resembles the legs of a tarantula 3 December 2009 ESO IDA Danish 1.5 m R. Gendler, C. C. Thöne, C. Féron, and J.-E. Ovaldsen

Schneider explained, “We found around 30% more stars with masses more than 30 times that of the Sun than expected, and about 70% more than expected above 60 solar masses. Our results challenge the previously predicted 150 solar mass limit for the maximum birth mass of stars and even suggest that stars could have birth masses up to 300 solar masses!”

Rob Ivison, co-author of the new ALMA paper, concludes: “Our findings lead us to question our understanding of cosmic history. Astronomers building models of the Universe must now go back to the drawing board, with yet more sophistication required.”
Notes

[1] Starburst galaxies are galaxies that are undergoing an episode of very intense star formation. The rate at which they form new stars can be 100 times or more the rate in our own galaxy, the Milky Way. Massive stars in these galaxies produce ionising radiation, stellar outflows, and supernova explosions, which significantly influence the dynamical and chemical evolution of the medium around them. Studying the mass distribution of stars in these galaxies can tell us more about their own evolution, and also the evolution of the Universe more generally.

[2] The radiocarbon dating method is used for determining the age of an object containing organic material. By measuring the amount of 14C, which is a radioactive isotope whose abundance continuously decreases, one can calculate when the animal or plant died. The isotopes used in the ALMA study, 13C and 18O, are stable and their abundances continuously increase during the lifetime of a galaxy, being synthesised by thermal nuclear fusion reactions inside stars.

[3] These different forms of the molecule are called isotopologues and they differ in the number of neutrons they can have. The carbon monoxide molecules used in this study are an example of such molecular species, because a stable carbon isotope can have either 12 or 13 nucleons in its nucleus, and a stable oxygen isotope can have either 16, 17, or 18 nucleons.

[4] Schneider et al. made spectroscopic observations of individual stars in 30 Doradus, a star-forming region in the nearby Large Magellanic Cloud, using the Fibre Large Array Multi Element Spectrograph (FLAMES) on the Very Large Telescope (VLT).

ESO/FLAMES on The VLT. FLAMES is the multi-object, intermediate and high resolution spectrograph of the VLT. Mounted at UT2, FLAMES can access targets over a field of view 25 arcmin in diameter. FLAMES feeds two different spectrograph covering the whole visual spectral range:GIRAFFE and UVES.

Large Magellanic Cloud. Adrian Pingstone December 2003

This study was one of the first to be carried out that has been detailed enough to show that the Universe is able to produce star-forming regions with different mass distributions from that in the Milky Way.

Galaxies in the distant Universe are seen during their youth and therefore have relatively short and uneventful star formation histories. This makes them an ideal laboratory to study the earliest epochs of star formation. But at a price — they are often enshrouded by obscuring dust that hampers the correct interpretation of the observations. Credit: ESO/M. Kornmesser

This kind of galaxy is typically forming stars at such a high rate that astronomers often refer to them as “starbursts”. They can form up to 1000 times more stars per year, compared to the Milky Way. Thanks to the unique capabilities of ALMA, astronomers have been able to measure the proportion of high-mass stars in such starburst galaxies. Credit: ESO/M. Kornmesser

More information

The ALMA results are published in a paper entitled Stellar populations dominated by massive stars in dusty starburst galaxies across cosmic time that will appear in Nature on 4 June 2018. The VLT results are published in a paper entitled An excess of massive stars in the local 30 Doradus starburst, which has been published in Science on 5 January 2018.

The ALMA team is composed of: Z. Zhang (Institute for Astronomy, University of Edinburgh, Edinburgh, UK; European Southern Observatory, Garching bei München, Germany), D. Romano (INAF, Astrophysics and Space Science Observatory, Bologna, Italy), R. J. Ivison (European Southern Observatory, Garching bei München, Germany; Institute for Astronomy, University of Edinburgh, Edinburgh, UK), P .P. Papadopoulos (Department of Physics, Aristotle University of Thessaloniki, Thessaloniki, Greece; Research Center for Astronomy, Academy of Athens, Athens, Greece;) and F. Matteucci (Trieste University; INAF, Osservatorio Astronomico di Trieste; INFN, Sezione di Trieste, Trieste, Italy)

The VLT team is composed of: F. R. N. Schneider ( Department of Physics, University of Oxford, UK), H. Sana (Institute of Astrophysics, KU Leuven, Belgium), C. J. Evans ( UK Astronomy Technology Centre, Royal Observatory Edinburgh, Edinburgh, UK), J. M. Bestenlehner (Max-Planck-Institut für Astronomie, Heidelberg, Germany; Department of Physics and Astronomy, University of Sheffield, UK), N. Castro (Department of Astronomy, University of Michigan, USA), L. Fossati (Austrian Academy of Sciences, Space Research Institute, Graz, Austria), G. Gräfener (Argelander-Institut für Astronomie der Universität Bonn, Germany), N. Langer (Argelander-Institut für Astronomie der Universität Bonn, Germany), O. H. Ramírez-Agudelo (UK Astronomy Technology Centre, Royal Observatory Edinburgh, Edinburgh, UK), C. Sabín-Sanjulián (Departamento de Física y Astronomía, Universidad de La Serena, Chile), S. Simón-Díaz (Instituto de Astrofísica de Canarias, Tenerife, Spain; Departamento de Astrofísica, Universidad de La Laguna, Tenerife, Spain), F. Tramper (European Space Astronomy Centre, Madrid, Spain), P. A. Crowther (Department of Physics and Astronomy, University of Sheffield, UK), A. de Koter (Astronomical Institute Anton Pannekoek, Amsterdam University, Netherlands; Institute of Astrophysics, KU Leuven, Belgium), S. E. de Mink (Astronomical Institute Anton Pannekoek, Amsterdam University, Netherlands), P. L. Dufton (Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast, Northern Ireland, UK), M. Garcia (Centro de Astrobiología, CSIC-INTA, Madrid, Spain), M. Gieles (Department of Physics, Faculty of Engineering and Physical Sciences, University of Surrey, UK), V. Hénault-Brunet (National Research Council, Herzberg Astronomy and Astrophysics, Canada; Department of Astrophysics/Institute for Mathematics, Astrophysics and Particle Physics, Radboud University, Netherlands), A. Herrero (Departamento de Física y Astronomía, Universidad de La Serena, Chile), R. G. Izzard (Department of Physics, Faculty of Engineering and Physical Sciences, University of Surrey, UK; Institute of Astronomy, The Observatories, Cambridge, UK), V. Kalari (Departamento de Astronomía, Universidad de Chile, Santiago, Chile), D. J. Lennon (European Space Astronomy Centre, Madrid, Spain), J. Maíz Apellániz (Centro de Astrobiología, CSIC–INTA, European Space Astronomy Centre campus, Villanueva de la Cañada, Spain), N. Markova (Institute of Astronomy with National Astronomical Observatory, Bulgarian Academy of Sciences, Smolyan, Bulgaria), F. Najarro (Centro de Astrobiología, CSIC-INTA, Madrid, Spain), Ph. Podsiadlowski (Department of Physics, University of Oxford, UK; Argelander-Institut für Astronomie der Universität Bonn, Germany), J. Puls (Ludwig-Maximilians-Universität München, Germany), W. D. Taylor (UK Astronomy Technology Centre, Royal Observatory Edinburgh, Edinburgh, UK), J. Th. van Loon (Lennard-Jones Laboratories, Keele University, Staffordshire, UK), J. S. Vink (Armagh Observatory, Northern Ireland, UK) and C. Norman (Johns Hopkins University, Baltimore, USA; Space Telescope Science Institute, Baltimore, USA)

Links

Zhang et al. research paper
Schneider et al. research paper
Photos of ALMA
Photos of the VLT

See the full ESO article here .

Please help promote STEM in your local schools.

Stem Education Coalition

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

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.