Smoking-gun evidence for neutrinos’ role in supernova explosions

Figure 1: The Cassiopeia A supernova remnant has iron-rich plumes that contain titanium and chromium (areas with thick yellow outlines on right). This observation provides support for a model in which neutrinos help drive supernova explosions. © 2021 NASA/CXC/RIKEN/T. Sato et al.; NuSTAR: NASA/NuSTAR

Supernova explosions are sustained by neutrinos from neutron stars, a new observation suggests

A model for supernova explosions first proposed in the 1980s has received strong support from the observation by RIKEN astrophysicists of titanium-rich plumes emanating from a remnant of such an explosion1.

Some supernova explosions are the death throes of stars that are at least eight times more massive than our Sun. They are one of the most cataclysmic events in the Universe, unleashing as much energy in a few seconds as the Sun will generate in 10 billion years.

In contrast, neutrinos are among the most ethereal of members of the elementary-particle zoo—they are at least 5 million times lighter than an electron and about 10 quadrillion of them flit through your body every second without interacting with it.

It’s hard to conceive that there could be any connection between supernovas and neutrinos, but a model advanced in the 1980s proposed that supernovas would not occur if it were not for the heating provided by neutrinos.

This type of supernova starts when the core of a massive star collapses into a neutron star—an incredibly dense star that is roughly 20 kilometers in diameter. The remainder of the star collapses under gravity, hits the neutron star, and rebounds off it, creating a shockwave.

However, many supernova models predict that this shockwave will fade before it can escape the star’s gravity. Factoring in heating generated by neutrinos ejected from the neutron star could provide the energy needed to sustain shockwaves and hence the supernova explosion.

Now, Shigehiro Nagataki at the RIKEN Astrophysical Big Bang Laboratory, Toshiki Sato, who was at the RIKEN Nishina Center for Accelerator-Based Science at the time of the study, and co-workers have found strong evidence supporting this model by detecting titanium and chromium in iron-rich plumes of a supernova remnant.

The neutrino-driven supernova model predicts that trapped neutrinos will generate plumes of high-entropy material, leading to bubbles in supernova remnants rich in metals such as titanium and chromium. That is exactly what Nagataki and his team saw in their spectral analysis based on observational data from the Chandra X-ray Observatory on Cassiopeia A (Fig. 1), a supernova remnant from about 350 years ago. This observation is thus strong confirmation that neutrinos play a role in driving supernova explosions.

“The chemical compositions we measured strongly suggest that these materials were driven by neutrino-driven winds from the surface of the neutron star,” says Nagataki. “Thus, the bubbles we found had been conveyed from the heart of the supernova to the outer rim of the supernova remnant.”

Nagataki’s team now intends to perform numerical simulations using supercomputers to model the process in more detail. “Our finding provides a strong impetus for revisiting the theory of supernova explosions,” Nagataki adds.

Related contents

• Radioactive elements in Cassiopeia A suggest a neutrino-driven explosion
• Rare-metal abundance points to a missing companion star for the supernova Cassiopeia A
• Clumpy structure in remnant probably formed in supernova explosion itself

Reference:

1.Sato, T., Maeda, K., Nagataki, S., Yoshida, T., Grefenstette, B., Williams, B. J., Umeda, H., Ono, M. & Hughes, J. P. High-entropy ejecta plumes in Cassiopeia A from neutrino-driven convection . Nature 592 537–540 (2021). doi: 10.1038/s41586-021-03391-9The webpage will open in a new tab.

Source: RIKEN/News

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Scientists capture most-detailed radio image of Andromeda galaxy to date

Radio image of Andromeda galaxy at 6.6 GHz (inset), captured using the Sardinia Radio Telescope in Italy

Credit: S. Fatigoni et al. (2021)

‘Disk of galaxy’ identified as region where new stars are born

Scientists have published a new, detailed radio image of the Andromeda galaxy – the Milky Way’s sister galaxy – which will allow them to identify and study the regions of Andromeda where new stars are born.

The study – which is the first to create a radio image of Andromeda at the microwave frequency of 6.6 GHz – was led by University of British Columbia physicist Sofia Fatigoni, with colleagues at Sapienza University of Rome and the Italian National Institute of Astrophysics. It was published online in Astronomy and Astrophysics.

“This image will allow us to study the structure of Andromeda and its content in more detail than has ever been possible,” said Fatigoni, a PhD student in the department of physics and astronomy at UBC. “Understanding the nature of physical processes that take place inside Andromeda allows us to understand what happens in our own galaxy more clearly – as if we were looking at ourselves from the outside.”

Prior to this study, no maps capturing such a large region of the sky around the Andromeda Galaxy had ever been made in the microwave band frequencies between one GHz to 22 GHz. In this range, the galaxy’s emission is very faint, making it hard to see its structure. However, it is only in this frequency range that particular features are visible, so having a map at this particular frequency is crucial to understanding which physical processes are happening inside Andromeda.

In order to observe Andromeda at this frequency, the researchers required a single-dish radio telescope with a large effective area. For the study, the scientists turned to the Sardinia Radio Telescope, a 64-metre fully steerable telescope capable of operating at high radio frequencies, located in Italy.

The Sardinia Radio Telescope, located in Sardinia, Italy

Credit: S. Fatigoni et al (2021)

It took 66 hours of observation and consistent data analysis for the researchers to map the galaxy with high sensitivity.

They were then able to estimate the rate of star formation within Andromeda, and produce a detailed map that highlighted the ‘disk of the galaxy,’ as the region where new stars are born.

“By combining this new image with those previously acquired, we have made significant steps forward in clarifying the nature of Andromeda’s microwave emissions and allowing us to distinguish physical processes that occur in different regions of the galaxy,” said Dr. Elia Battistelli, a professor in the department of physics at Sapienza and coordinator of the study.

“In particular, we were able to determine the fraction of emissions due to thermal processes related to the early stations of new star formation, and the fraction of radio signals attributable to non-thermal mechanisms due to cosmic rays that spiral in the magnetic field present in the interstellar medium,” Fatigoni said.

Final image of the Andromeda galaxy after averaging over the whole bandwidth at 6.6 GHz

Credit: S. Fatigoni et al (2021)

For the study, the team also developed and implemented software that allowed them to test new algorithms to identify never-before-examined lower emission sources in the field of view around Andromeda at a frequency of 6.6 GHz.

From the resulting map, researchers were able to identify a catalog of about 100 ‘point sources’ including stars, galaxies and other objects in the background of Andromeda.

Interview language(s): English, Italian

Note for reporters: Sofia Fatigoni is based in Rome, Italy and is available for interviews until 3 p.m. PST.

Contact: 

Sachintha Wickramasinghe
UBC Media Relations
Tel: 604-822-4636
Cel: 604-754-8289
Email: sachi.wickramasinghe@ubc.ca

Source:  University of British Columbia - UBC/News

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XMM-Newton sees light echo from behind a black hole

Ligh echoes behind a Black Hole

For the first time, astronomers have seen light coming from behind a black hole.

Using ESA’s XMM-Newton and NASA’s NuSTAR space telescopes, an international team of scientists led by Dan Wilkins of Stanford University in the USA observed extremely bright flares of X-ray light coming from around a black hole.

The X-ray flares echoed off of the gas falling into the black hole, and as the flares were subsiding, the telescopes picked up fainter flashes, which were the echoes of the flares bouncing off the gas behind the black hole.

This supermassive black hole is 10 million times as massive as our Sun and located in the centre of a nearby spiral galaxy called I Zwicky 1, 800 million light-years away from Earth.

The astronomers did not expect to see anything from behind the black hole, since no light can escape from it. But because of the black hole’s extreme gravity warping the space around it, light echoes from behind the black hole were bent around the black hole, making them visible from XMM and NuSTAR’s point of view.

The discovery began with the search to find out more about the mysterious ‘corona’ of the black hole, which is the source of the bright X-ray light. Astronomers think that the corona is a result of gas that falls continuously into the black hole, where it forms a spinning disk around it – like water flushing down a drain.

This gas disk is heated up to millions of degrees and generates magnetic fields that get twisted into knots by the spinning black hole. When the magnetic field gets tied up, it eventually snaps, releasing the energy stored within it. This heats everything around it and produces the corona of high energy electrons that produce the X-ray light.

The X-ray flare observed from I Zwicky 1 was so bright that some of the X-rays shone down onto the disk of gas falling into the black hole. The X-rays that reflected on the gas behind the black hole were bent around the black hole, and these smaller flashes arrived at the telescopes with a delay. These observations match Einstein’s predictions of how gravity bends light around black holes, as described in his theory of General Relativity.

The echoes of X-rays from the disk have specific ‘colours’ of light and as the X-rays travel around the black hole, their colours change slightly. Because the X-ray echoes have different colours and are seen at different times, depending where on the disk they reflected from, they contain a lot of information about what is happening around a black hole. The astronomers want to use this technique to create a 3D map of the black hole surroundings.

Another mystery to be solved in future studies is how the corona produces such bright X-ray flares. The mission to characterise and understand black hole coronas will continue with XMM-Newton and ESA’s future X-ray observatory, Athena (Advanced Telescope for High-ENergy Astrophysics).

The team published their findings in Nature. DOI: 10.1038/s41586-021-03667-0

Source: ESA/Space Science

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Magnetic ‘Balding’ of Black Holes Saves General Relativity Prediction

A simulation of the magnetic field lines (green) surrounding a black hole (left). As the field lines break and reconnect, pockets of plasma form (center of green circles). These plasma pockets launch inward toward the black hole or outward into space, draining energy from the magnetic field. A. Bransgrove et al./Physical Review Letters 2021

Magnetic fields around black holes decay quickly, report researchers from the Flatiron Institute, Columbia University and Princeton University. This finding backs up the so-called ‘no-hair conjecture’ predicted by Einstein’s general relativity.

Black holes aren’t what they eat. Einstein’s general relativity predicts that no matter what a black hole consumes, its external properties depend only on its mass, rotation and electric charge. All other details about its diet disappear. Astrophysicists whimsically call this the no-hair conjecture. (Black holes, they say, “have no hair.”)

There is a potentially hairy threat to the conjecture, though. Black holes can be born with a strong magnetic field or obtain one by munching on magnetized material. Such a field must quickly disappear for the no-hair conjecture to hold. But real black holes don’t exist in isolation. They can be surrounded by plasma — gas so energized that electrons have detached from their atoms — that can sustain the magnetic field, potentially disproving the conjecture.

Using supercomputer simulations of a plasma-engulfed black hole, researchers from the Flatiron Institute’s Center for Computational Astrophysics (CCA) in New York City, Columbia University and Princeton University found that the no-hair conjecture holds. The team reports its findings on July 27 in Physical Review Letters.

“The no-hair conjecture is a cornerstone of general relativity,” says study co-author Bart Ripperda, a research fellow at the CCA and a postdoctoral fellow at Princeton. “If a black hole has a long-lived magnetic field, then the no-hair conjecture is violated. Luckily a solution came from plasma physics that saved the no-hair conjecture from being broken.”

The team’s simulations showed that the magnetic field lines around the black hole quickly break and reconnect, creating plasma-filled pockets that launch into space or fall into the black hole’s maw. This process rapidly drains the magnetic field and could explain flares seen near supermassive black holes, the researchers report.

“Theorists didn’t think of this because they usually put their black holes in a vacuum,” Ripperda says. “But in real life, there’s often plasma, and plasma can sustain and bring in magnetic fields. And that has to fit with your no-hair conjecture.”

Ripperda co-authored the study with Columbia graduate student Ashley Bransgrove and CCA associate research scientist Sasha Philippov, who is also a visiting research scholar at Princeton.

A simulation of the magnetic field (green lines) and plasma around a black hole (left). Initially, the field lines arc from one of the black hole’s magnetic poles to the other. Over time, the field lines balloon outward, creating rows of alternating orientation. The field lines then begin breaking and reconnecting. That process creates pockets of plasma that shoot into space or fall toward the black hole. A. Bransgrove et al./Physical Review Letters 2021. Video

A 2011 study on the problem suggested that the no-hair conjecture was in trouble. However, that study only looked at these systems at low resolution, and it treated plasma as a fluid. However, the plasma around a black hole is so diluted that particles rarely run into one another, so treating it as a fluid is an oversimplification.

In the new study, the researchers conducted high-resolution plasma physics simulations with a general-relativistic model of a black hole’s magnetic field. In total, it took 10 million CPU hours to churn through all the calculations. “We couldn’t have done these simulations without the Flatiron Institute’s computational resources,” Ripperda says.

The resulting simulations showed how the magnetic field around a black hole evolves. At first, the field extends in an arc from the black hole’s north pole to its south pole. Then, interactions within the plasma cause the field to balloon outward. This opening up causes the field to split into individual magnetic field lines that radiate outward from the black hole.

The field lines alternate in direction, either toward or away from the event horizon. Nearby magnetic field lines connect, creating a braided pattern of field lines coming together and splitting apart. Between two such connection points, a gap exists that fills with plasma. The plasma is energized by the magnetic field, launching outward into space or inward into the black hole. As the process continues, the magnetic field loses energy and eventually withers away.

Critically, the process happens fast. The researchers found that the black hole depletes its magnetic field at a rate of 10 percent of the speed of light. “The fast reconnection saved the no-hair conjecture,” Ripperda says.

The researchers propose that the mechanism powering observed flares from the supermassive black hole at the center of the Messier 87 galaxy could be explained by the balding process seen in the simulations. Initial comparisons between them look promising, they say, though a more robust assessment is needed. If they do indeed line up, energetic flares powered by magnetic reconnection at black hole event horizons may be a widespread phenomenon.

The authors acknowledge support by the National Science Foundation under Grants No. PHY-2010145.

By Thomas Sumner

Information for Press

For more information, please contact: Stacey Greenebaum at press@simonsfoundation.org.

• Link to scientific paper
• Link to high-res graphic
• Link to video download

Source:  Center for Computational Astrophysics (CCA)/News

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Hubble Finds First Evidence of Water Vapour at Jupiter’s Moon Ganymede

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Hubble’s View of Ganymede in 1996

 

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Hubble’s Ultraviolet Observations of Ganymede in 1998

 

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Artist’s Impression of Ganymede

 

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Artist’s Impression of Ganymede

 

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Artist’s Impression of a Sublimated Water Atmosphere on Ganymede

 

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NASA’s Juno Spacecraft Observation of Ganymede in June 2021

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Astronomers have used archival datasets from the NASA/ESA Hubble Space Telescope to reveal the first evidence for water vapour in the atmosphere of Jupiter’s moon Ganymede, the result of the thermal escape of water vapour from the moon’s icy surface.

Jupiter’s moon Ganymede is the largest moon — and the ninth-largest object — in the Solar System. It may hold more water than all of Earth's oceans, but temperatures there are so cold that water on the surface freezes and the ocean lies roughly 160 kilometres below the crust. Nevertheless, where there is water there could be life as we know it. Identifying liquid water on other worlds is crucial in the search for habitable planets beyond Earth. And now, for the first time, evidence has been found for a sublimated water atmosphere on the icy moon Ganymede.

In 1998,  Hubble’s Space Telescope Imaging Spectrograph (STIS) took the first ultraviolet (UV) pictures of Ganymede, which revealed a particular pattern in the observed emissions from the moon’s atmosphere. The moon displays auroral bands that are somewhat similar to the auroral ovals observed on Earth and other planets with magnetic fields. These images were therefore illustrative evidence that Ganymede has a permanent magnetic field. The similarities between the two ultraviolet observations were explained by the presence of molecular oxygen, O2. The differences were explained at the time by the presence of atomic oxygen, O, which produces a signal that affects one UV colour more than the other. 

As part of a large observing programme to support NASA’s Juno mission in 2018, Lorenz Roth, of the KTH Royal Institute of Technology in Stockholm, Sweden, led a team that set out to capture UV spectra of Ganymede with Hubble’s Cosmic Origins Spectrograph (COS) instrument to measure the amount of atomic oxygen. They carried out a  combined analysis of new spectra taken in 2018 with the COS and archival images from the STIS instrument from 1998 and 2010. To their surprise, and in contrast to the original interpretations of the data from 1998, they discovered there was hardly any atomic oxygen in Ganymede's atmosphere. This means there must be another explanation for the apparent differences between the UV aurora images.

The explanation was then uncovered by Roth and his team in the relative distribution of the aurorae in the two images. Ganymede's surface temperature varies strongly throughout the day, and around noon near the equator it may become sufficiently warm that the icy surface releases some small amounts of water molecules. In fact, the perceived differences between the UV images are directly correlated with where water would be expected in the moon’s atmosphere. 

“Initially only the O2 had been observed,” explained Roth. “This is produced when charged particles erode the ice surface. The water vapour that we have now measured originates from ice sublimation caused by the thermal escape of H2O vapour from warm icy regions.”

This finding adds anticipation to ESA’s upcoming JUpiter ICy moons Explorer (JUICE) mission — the first large-class mission in ESA's Cosmic Vision 2015–2025 programme. Planned for launch in 2022 and arrival at Jupiter in 2029, it will spend at least three years making detailed observations of Jupiter and three of its largest moons, with particular emphasis on Ganymede as a planetary body and potential habitable world. Ganymede was identified for detailed investigation because it provides a natural laboratory for the analysis of the nature, evolution and potential habitability of icy worlds in general and the role it plays within the system of Galilean satellites, and its unique magnetic and plasma interactions with Jupiter and its environment (known as the Jovian system).

“Our results can provide the JUICE instrument teams with valuable information that may be used to refine their observation plans to optimise the use of the spacecraft,” added Roth. 

Understanding the Jovian system and unravelling its history, from its origin to the possible emergence of habitable environments, will provide us with a better understanding of how gas giant planets and their satellites form and evolve. In addition, new insights will hopefully be found into the potential for the emergence of life in Jupiter-like exoplanetary systems.

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More Information

The Hubble Space Telescope is a project of international cooperation between ESA and NASA.

This image was taken as part of the HST observation programs GO-7939 (PI: H. Moos), GO-12244 (PI: J. Saur), and GO-14634 (PI: D. Grodent).

The results have been published in Nature Astronomy. The international team behind this paper consists of L. Roth (KTH Royal Institute of Technology, Sweden), N. Ivchenko (KTH Royal Institute of Technology, Sweden), G. R. Gladstone (Southwest Research Institute, Texas, USA), J. Saur (Institut für Geophysik und Meteorologie, Germany), D. Grodent (Laboratoire de Physique Atmosphérique et Planétaire, Belgium), B. Bonfond (Laboratoire de Physique Atmosphérique et Planétaire, Belgium), P. M. Molyneux (Southwest Research Institute, Texas, USA), and K. D. Retherford (Southwest Research Institute, Texas, USA).

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Links

• Images of Hubble 
• HubbleSite release
• Link to science paper

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Contacts

Lorenz Roth
KTH Royal Institute of Technology
Stockholm, Sweden
Email: lorenzr@kth.se

Bethany Downer
ESA/Hubble Chief Communications Officer
Email: Bethany.Downer@esahubble.org

Source:ESA/News

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Astronomers Uncover Briefest Supernova-Powered Gamma-Ray Burst

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Illustration of a Short Gamma-Ray Burst Caused by a Collapsing Star

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Gemini North identifies collapsing star as the surprising cause of a “fizzled” gamma-ray burst

Astronomers have discovered the shortest-ever gamma-ray burst (GRB) caused by the implosion of a massive star. Using the international Gemini Observatory, a Program of NSF’s NOIRLab, astronomers identified the cause of this 0.6-second flurry of gamma rays as a supernova explosion in a distant galaxy. GRBs caused by supernovae are usually more than twice as long, which suggests that some short GRBs might actually be imposters — supernova-produced GRBs in disguise.

Gamma-ray bursts (GRBs) are among the brightest and most energetic events in the Universe, but scientists are still figuring out exactly what causes these fleeting events [1]. Astronomers divide GRBs into two broad categories based on their duration. Short GRBs blaze into life in less than two seconds and are thought to be caused by the merging of binary neutron stars [2]. Those that last longer are classified as long GRBs, and have been associated with supernova explosions caused by the implosions of massive stars [3]. However, the recent discovery of the shortest-ever GRB produced during a supernova shows that GRBs don’t fit neatly into the boxes astronomers have created for them.

“This discovery represents the shortest gamma-ray emission caused by a supernova during the collapse of a massive star,” commented Tomás Ahumada, who led this research and is a PhD candidate at the University of Maryland and astronomer at NASA’s Goddard Space Flight Center. “It lasted for only 0.6 second, and it sits on the brink between a successful and a failed gamma-ray burst.”

The team believes that this and some other supernova-related GRBs are appearing short because the jets of gamma rays that emerge from the collapsing star’s poles aren’t strong enough to completely escape the star — almost failing to produce a GRB — and that other collapsing stars have such weak jets that they don’t produce GRBs at all.

This discovery could also help explain an astronomical mystery. Long GRBs are associated with a specific type of supernova (called Type Ic-BL). However, astronomers observe many more of these supernovae than long GRBs. This discovery of the shortest GRB associated with a supernova suggests that some of these supernova-caused GRBs are masquerading as short GRBs thought to be created by neutron-star mergers, and are therefore not getting counted as the supernova kind.

“Our discovery suggests that, since we observe many more of these supernovae than long gamma-ray bursts, most collapsing stars fail to produce a GRB jet that breaks through the outer envelope of the collapsing star,” explained Ahumada. “We think this event was effectively a fizzle, one that was close to not happening at all.” 

The team was able to determine that this GRB — identified as GRB 200826A — originated from a supernova explosion thanks to the imaging capabilities of the Gemini Multi-Object Spectrograph on Gemini North in Hawai‘i. The researchers used Gemini North to obtain images of the GRB’s host galaxy 28, 45, and 80 days after the GRB was first detected on 26 August 2020 by a network of observatories that included NASA’s Fermi Gamma-ray Space Telescope. Gemini’s observations allowed the team to spot the tell-tale rise in energy that signifies a supernova, despite the blast’s location in a galaxy 6.6 billion light-years away.

“This was a complicated endeavor as we needed to separate the light of an already faint galaxy from the light of a supernova,” said Ahumada. “Gemini is the only ground-based telescope that can do follow-up observations like this with a flexible-enough schedule to let us squeeze in our observations.” 

This result shows that classifying GRBs based solely on their duration may not be the best approach, and that additional observations are needed to determine a GRB’s cause.

"We were originally hunting for merging neutron stars, which are thought to produce short gamma-ray bursts," added Ahumada. "Once we discovered GRB 200826A, however, we realized that this burst was more likely to be caused by a collapsing star’s supernova, which was a surprise!"

“The Gemini observatories continue to shed new light on the nature of these incredible explosions occurring across the distant Universe,” said Martin Still, Gemini Program Officer at NSF. “Dedicated instrumentation arriving for use over the next decade will maintain Gemini’s leadership in the follow-up of these awe-inspiring cosmic events.”

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Notes

[1] Gamma-ray bursts occur extremely rarely, but when they do occur they release a spectacular amount of energy. In just a few seconds, a typical GRB will release more energy than the Sun will over its 10-billion-year lifetime.

[2] Neutron stars are some of the smallest, densest, and strangest astronomical objects in the Universe. Formed by the collapse of massive stars, they compress the mass of 1.4 Suns into a ball only 10 kilometers across. The material of neutron stars is as dense as the nucleus of an atom, and a single teaspoon of neutron-star material would weigh as much as Mount Everest on Earth. As well as their incredible density, neutron stars are also intensely hot and possess magnetic fields millions of times stronger than Earth’s.

[3] A star that has collapsed under its own gravity at the end of its life is also known as a collapsar. At the end of their lives, stars run out of the hydrogen that sustains nuclear reactions in their cores. Without the stabilizing pressure of these reactions, stars cannot fight gravity, and they collapse into an exotic stellar remnant. The mass of a star determines its fate: stars smaller than 1.4 times the mass of the Sun shrink to white dwarfs, larger stars collapse into neutron stars, and the largest stars collapse entirely, forming black holes.

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More Information

This research was presented in the paper Discovery and Confirmation of the Shortest Gamma Ray Burst from a Collapsar in the journal Nature Astronomy.

The team is composed of Tomás Ahumada (Department of Astronomy, University of Maryland; Astrophysics Science Division, NASA Goddard Space Flight Center; and Center for Research and Exploration in Space Science and Technology, NASA Goddard Space Flight Center), Leo P. Singer (Astrophysics Science Division, NASA Goddard Space Flight Center; Joint Space-Science Institute, University of Maryland), Shreya Anand (Division of Physics, Mathematics and Astronomy, California Institute of Technology), Michael W. Coughlin (School of Physics and Astronomy, University of Minnesota), Mansi M. Kasliwal (Division of Physics, Mathematics, and Astronomy, California Institute of Technology), Geoffrey Ryan (Department of Astronomy, University of Maryland; Astrophysics Science Division, NASA Goddard Space Flight Center), Igor Andreoni (Division of Physics, Mathematics, and Astronomy, California Institute of Technology), S. Bradley Cenko (Astrophysics Science Division, NASA Goddard Space Flight Center; Joint Space-Science Institute, University of Maryland), Christoffer Fremling (Division of Physics, Mathematics, and Astronomy, California Institute of Technology), Harsh Kumar (Indian Institute of Technology Bombay; LSSTC Data Science Fellow), Peter T. H. Pang (Nikhef, Department of Physics, Utrecht University), Eric Burns (Louisiana State University), Virginia Cunningham (Department of Astronomy, University of Maryland; Astrophysics Science Division, NASA Goddard Space Flight Center), Simone Dichiara (Department of Astronomy, University of Maryland; Astrophysics Science Division, NASA Goddard Space Flight Center), Tim Dietrich (Institut für Physik und Astronomie, Universität Potsdam; Max Planck Institute for Gravitational Physics, Albert Einstein Institute), Dmitry S. Svinkin (Ioffe Institute, Polytekhnicheskaya), Mouza Almualla (American University of Sharjah), Alberto J. Castro-Tirado (Instituto de Astrofísica de Andalucía; Departamento de Ingeniería de Sistemas y Automática, Escuela de Ingenieros Industriales), Kishalay De (Division of Physics, Mathematics, and Astronomy, California Institute of Technology), Rachel Dunwoody (School of Physics, University College Dublin), Pradip Gatkine (Division of Physics, Mathematics, and Astronomy, California Institute of Technology), Erica Hammerstein (Department of Astronomy, University of Maryland), Shabnam Iyyani (Inter-University Centre for Astronomy and Astrophysics), Joseph Mangan (School of Physics, University College Dublin), Dan Perley (Astrophysics Research Institute, Liverpool John Moores University), Sonalika Purkayastha (National Centre for Radio Astrophysics, Tata Institute of Fundamental Research), Eric Bellm (DIRAC Institute, Department of Physics and Astronomy, University of Washington), Varun Bhalerao (Indian Institute of Technology Bombay), Bryce Bolin (Division of Physics, Mathematics, and Astronomy, California Institute of Technology), Mattia Bulla (Nordita, KTH Royal Institute of Technology and Stockholm University), Christopher Cannella (Duke University, Electrical and Computer Engineering), Poonam Chandra (National Centre for Radio Astrophysics and Swarna Jayanti Fellow, Department of Science & Technology), Dmitry A. Duev (Division of Physics, Mathematics, and Astronomy, California Institute of Technology), Dmitry Frederiks (Ioffe Institute, Polytekhnicheskaya), Avishay Gal-Yam (Department of Particle Physics and Astrophysics, Hebrew University), Matthew Graham (Division of Physics, Mathematics, and Astronomy, California Institute of Technology), Anna Y. Q. Ho (Miller Institute for Basic Research in Science, University of California; Department of Astronomy, University of California – Berkeley), Kevin Hurley (Space Sciences Laboratory, University of California – Berkeley), Viraj Karambelkar (Division of Physics, Mathematics, and Astronomy, California Institute of Technology), Erik C. Kool (The Oskar Klein Centre, Department of Astronomy), S. R. Kulkarni (Division of Physics, Mathematics, and Astronomy, California Institute of Technology), Ashish Mahabal (Division of Physics, Mathematics, and Astronomy, California Institute of Technology), Frank Masci (IPAC, California Institute of Technology), Sheila McBreen (School of Physics, University College Dublin), Shashi B. Pandey (Aryabhatta Research Institute of Observational Sciences), Simeon Reusch (Deutsches Elektronen Synchrotron DESY; Institut für Physik, Humboldt-Universität zu Berlin), Anna Ridnaia (Ioffe Institute, Polytekhnicheskaya), Philippe Rosnet (Université Clermont Auvergne, CNRS; IN2P3, Laboratoire de Physique de Clermont), Benjamin Rusholme (IPAC, California Institute of Technology), Ana Sagués Carracedo (The Oskar Klein Centre, Department of Physics), Roger Smith (Caltech Optical Observatories, California Institute of Technology), Maayane Soumagnac (Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Lawrence Berkeley National Laboratory), Robert Stein (Deutsches Elektronen Synchrotron DESY; and Institut für Physik, Humboldt-Universität zu Berlin), Eleonora Troja (Department of Astronomy, University of Maryland; Astrophysics Science Division, NASA Goddard Space Flight Center), Anastasia Tsvetkova (Ioffe Institute, Polytekhnicheskaya), Richard Walters (Caltech Optical Observatories, California Institute of Technology), and Azamat F. Valeev (Special Astrophysical Observatory, Russian Academy of Sciences).

NSF’s NOIRLab (National Optical-Infrared Astronomy Research Laboratory), the US center for ground-based optical-infrared astronomy, operates the international Gemini Observatory (a facility of NSF, NRC–Canada, ANID–Chile, MCTIC–Brazil, MINCyT–Argentina, and KASI–Republic of Korea), Kitt Peak National Observatory (KPNO), Cerro Tololo Inter-American Observatory (CTIO), the Community Science and Data Center (CSDC), and Vera C. Rubin Observatory (operated in cooperation with the Department of Energy’s SLAC National Accelerator Laboratory). It is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with NSF and is headquartered in Tucson, Arizona. The astronomical community is honored to have the opportunity to conduct astronomical research on Iolkam Du’ag (Kitt Peak) in Arizona, on Maunakea in Hawai‘i, and on Cerro Tololo and Cerro Pachón in Chile. We recognize and acknowledge the very significant cultural role and reverence that these sites have to the Tohono O'odham Nation, to the Native Hawaiian community, and to the local communities in Chile, respectively.

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Links

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University of Maryland and NASA Goddard Space Flight Center
Email: tahumada@astro.umd.edu

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Press and Internal Communications Officer
NSF’s NOIRLab
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Email: amanda.kocz@noirlab.edu

 Source: NOIRLab/News

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EHT pinpoints dark heart of the nearest radio galaxy

Distance scales uncovered in the Centaurus A jet. The top left image shows how the jet disperses into gas clouds that emit radio waves, captured by the ATCA and Parkes observatories. The top right panel displays a color composite image, with a 40x zoom compared to the first panel to match the size of the galaxy itself. Submillimeter emission from the jet and dust in the galaxy measured by the LABOCA/APEX instrument is shown in orange. X-ray emission from the jet measured by the Chandra spacecraft is shown in blue. Visible white light from the stars in the galaxy has been captured by the MPG/ESO 2.2-metre telescope. The next panel below shows a 165000x zoom image of the inner radio jet obtained with the TANAMI telescopes. The bottom panel depicts the new highest resolution image of the jet launching region obtained with the EHT at millimeter wavelengths with a 60000000x zoom in telescope resolution. Indicated scale bars are shown in light years and light days. One light year is equal to the distance that light travels within one year: about nine trillion kilometers. In comparison, the distance to the nearest-known star from our Sun is approximately four light years. One light day is equal to the distance that light travels within one day: about six times the distance between the Sun and Neptune. Credit: Radboud University; CSIRO/ATNF/I.Feain et al., R.Morganti et al., N.Junkes et al.; ESO/WFI; MPIfR/ESO/APEX/A. Weiss et al.; NASA/CXC/CfA/R. Kraft et al.; TANAMI/C. Mueller et al.; EHT/M. Janssen et al. Hi-res image

Highest resolution image of Centaurus A obtained with the Event Horizon Telescope on top of a color composite image of the entire galaxy. Credit: Radboud University; ESO/WFI; MPIfR/ESO/APEX/A. Weiss et al.; NASA/CXC/CfA/R. Kraft et al.; EHT/M. Janssen et al. Hi-res image

An international team anchored by the Event Horizon Telescope (EHT) Collaboration, which is known for capturing the first image of a black hole in the galaxy Messier 87, has now imaged the heart of the nearby radio galaxy Centaurus A in unprecedented detail. The astronomers pinpoint the location of the central supermassive black hole and reveal how a gigantic jet is being born. Most remarkably, only the outer edges of the jet seem to emit radiation, which challenges our theoretical models of jets. This work, led by Michael Janssen from the Max Planck Institute for Radio Astronomy in Bonn and Radboud University Nijmegen is published in Nature Astronomy on July 19th.

At radio wavelengths, Centaurus A emerges as one of the largest and brightest objects in the night sky. After it was identified as one of the first known extragalactic radio sources in 1949, Centaurus A has been studied extensively across the entire electromagnetic spectrum by a variety of radio, infrared, optical, X-ray, and gamma-ray observatories. At the center of Centaurus A lies a black hole with the mass of 55 million suns, which is right between the mass scales of the Messier 87 black hole (six and a half billion suns) and the one in the center of our own galaxy (about four million suns).

In a new paper in Nature Astronomy, data from the 2017 EHT observations have been analyzed to image Centaurus A in unprecedented detail. “This allows us for the first time to see and study an extragalactic radio jet on scales smaller than the distance light travels in one day. We see up close and personally how a monstrously gigantic jet launched by a supermassive black hole is being born”, says astronomer Michael Janssen.

Compared to all previous high-resolution observations, the jet launched in Centaurus A is imaged at a tenfold higher frequency and sixteen times sharper resolution. With the resolving power of the EHT, we can now link the vast scales of the source, which are as big as 16 times the angular diameter of the Moon on the sky, to their origin near the black hole in a region of merely the width of an apple on the Moon when projected on the sky. That is a magnification factor of one billion.

Understanding jets

Supermassive black holes residing in the center of galaxies like Centaurus A are feeding off gas and dust that is attracted by their enormous gravitational pull. This process releases massive amounts of energy and the galaxy is said to become ‘active’. Most matter lying close to the edge of the black hole falls in. However, some of the surrounding particles escape moments before capture and are blown far out into space: Jets – one of the most mysterious and energetic features of galaxies – are born.

Astronomers have relied on different models of how matter behaves near the black hole to better understand this process. But they still do not know exactly how jets are launched from its central region and how they can extend over scales that are larger than their host galaxies without dispersing out. The EHT aims to resolve this mystery.

The new image shows that the jet launched by Centaurus A is brighter at the edges compared to the center. This phenomenon is known from other jets, but has never been seen so pronouncedly before. “Now we are able to rule out theoretical jet models that are unable to reproduce this edge-brightening. It’s a striking feature that will help us better understand jets produced by black holes”, says Matthias Kadler, TANAMI leader and professor for astrophysics at the University of Würzburg in Germany.

Future observations

With the new EHT observations of the CentaurusA jet, the likely location of the black hole has been identified at the launching point of the jet. Based on this location, the researchers predict that future observations at an even shorter wavelength and higher resolution would be able to photograph the central black hole of Centaurus A. This will require the use of space-based satellite observatories.

“These data are from the same observing campaign that delivered the famous image of the black hole in M87. The new results show that the EHT provides a treasure trove of data on the rich variety of black holes and there is still more to come”, says Heino Falcke, EHT board member and professor for Astrophysics at Radboud University.

Additional Information

To observe the Centaurus A galaxy with this unprecedentedly sharp resolution at a wavelength of 1.3 mm, the EHT collaboration used Very Long Baseline Interferometry (VLBI), the same technique with which the famous image of the black hole in M87 was made. An alliance of eight telescopes around the world, of which ALMA is the most sensitive element, joined together to create the virtual Earth-sized Event Horizon Telescope. The EHT collaboration involves more than 300 researchers from Africa, Asia, Europe, North and South America.

The EHT consortium consists of 13 stakeholder institutes: the Academia Sinica Institute of Astronomy and Astrophysics, the University of Arizona, the University of Chicago, the East Asian Observatory, Goethe University Frankfurt, Institut de Radioastronomie Millimétrique (MPG/CNRS/IGN), Large Millimeter Telescope, Max Planck Institute for Radio Astronomy, MIT Haystack Observatory, National Astronomical Observatory of Japan, Perimeter Institute for Theoretical Physics, Radboud University and the Center for Astrophysics | Harvard & Smithsonian.

TANAMI (Tracking Active Galactic Nuclei with Austral Milliarcsecond Interferometry) is a multiwavelength program to monitor relativistic jets in active galactic nuclei of the Southern Sky. This program has been monitoring Centaurus A with VLBI at centimeter-wavelengths since the mid 2000s. The TANAMI array consists of nine radio telescopes located on four continents observing at wavelengths of 4 cm and 1.3 cm.

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of the European Organisation for Astronomical Research in the Southern Hemisphere (ESO), the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the Ministry of Science and Technology (MOST) and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI).

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

Scientific Paper 

Source:   Atacama Large Millimeter/submillimeter Array (ALMA)/Press Releases

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Joint ALMA Observatory Santiago - Chile

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Public Information & News Manager

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Hubble Views a Faraway Galaxy Through a Cosmic Lens

MACSJ0138.0-2155

Credit: ESA/Hubble & NASA, A. Newman, M. Akhshik, K. Whitaker

The center of this image from the NASA/ESA Hubble Space Telescope is framed by the tell-tale arcs that result from strong gravitational lensing, a striking astronomical phenomenon which can warp, magnify, or even duplicate the appearance of distant galaxies.

Gravitational lensing occurs when light from a distant galaxy is subtly distorted by the gravitational pull of an intervening astronomical object. In this case, the relatively nearby galaxy cluster MACSJ0138.0-2155 has lensed a significantly more distant inactive galaxy – a slumbering giant known as MRG-M0138 which has run out of the gas required to form new stars and is located 10 billion light-years away. Astronomers can use gravitational lensing as a natural magnifying glass, allowing them to inspect objects like distant dormant galaxies which would usually be too difficult for even Hubble to resolve.

This image was made using observations from eight different infrared filters spread across two of Hubble’s most advanced astronomical instruments: the Advanced Camera for Surveys and the Wide Field Camera 3. These instruments were installed by astronauts during the final two servicing missions to Hubble and provide astronomers with superbly detailed observations across a large area of sky and a wide range of wavelengths.

Media Contact:

Claire Andreoli
NASA's Goddard Space Flight Center
301-286-1940

Source: NASA/Solar System and Beyond

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Featured Image: Do Planets Make Only Puffy Gaps?

Streamlines showing the gas (top) and dust (bottom) motion in a disk, shown in cross-section, due to a planet orbiting at R/Rref=1.Credit: Bi et al. 2021. Hi-res image

Examples from DSHARP of some of the structure observed in protoplanetary disks. Click to enlarge.

Credit: Andrews et al. 2018. Hi-res image

In the simulated cross-section of a protoplanetary disk shown above (see the full figure below), dust swirls around as a consequence of the recent passage of an orbiting planet. This simulation was led by Jiaqing Bi (毕嘉擎; University of Victoria, Canada) to explore what happens to the disk of gas and dust surrounding a young star when a baby planet orbits within it.

Protoplanetary disks often exhibit a dramatic structure of gaps and rings. But in some systems, the edges of gaps are puffy and ill-defined, suggesting agitated dust; in others, the gaps are sharp and well-defined, suggesting the dust there is well-settled. Could the presence of an orbiting planet explain both kinds of structure?

Bi and collaborators use their 3D simulations to model how a planet stirs up the gas and dust at the edges of gaps, and show how the properties of both the planet and the dust affect how quickly the dust settles after the planet’s passage — and thus, how sharp the disk gaps appear. To find out more about the authors’ results, check out the original article below.

Citation

“Puffed-up Edges of Planet-opened Gaps in Protoplanetary Disks. I. Hydrodynamic Simulations,” Jiaqing Bi et al 2021 ApJ 912 107. doi:10.3847/1538-4357/abef6b

By Susanna Kohler

Source: American Astronomical Society (AAS/Nova)

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New Study Reveals Previously Unseen Star Formation in Milky Way

GLOSTAR image, using data from both the VLA and the Effelsberg radio telescope, shows a segment of the Milky Way's disk, revealing previously unseen tracers of massive star formation. Credit: Brunthaler et al., Sophia Dagenello, NRAO/AUI/NSF. Hi-Res File

GLOSTAR image, using data from both the VLA and the Effelsberg radio telescope, shows a segment of the Milky Way's disk, revealing previously unseen tracers of massive star formation. Some of these features are identified in this version of the image. Credit: Brunthaler et al., Sophia Dagenello, NRAO/AUI/NSF. Hi-Res File

Video highlights features within the GLOSTAR image

Credit: Brunthaler et al., Sophia Dagenello, NRAO/AUI/NSF

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Astronomers using two of the world’s most powerful radio telescopes have made a detailed and sensitive survey of a large segment of our home galaxy — the Milky Way — detecting previously unseen tracers of massive star formation, a process that dominates galactic ecosystems. The scientists combined the capabilities of the National Science Foundation’s Karl G. Jansky Very Large Array (VLA) and the 100-meter Effelsberg Telescope in Germany to produce high-quality data that will serve researchers for years to come.

Stars with more than about ten times the mass of our Sun are important components of the Galaxy and strongly affect their surroundings. However, understanding how these massive stars are formed has proved challenging for astronomers. In recent years, this problem has been tackled by studying the Milky Way at a variety of wavelengths, including radio and infrared. This new survey, called GLOSTAR (Global view of the Star formation in the Milky Way), was designed to take advantage of the vastly improved capabilities that an upgrade project completed in 2012 gave the VLA to produce previously unobtainable data.

GLOSTAR has excited astronomers with new data on the birth and death processes of massive stars, as well on the tenuous material between the stars. The GLOSTAR team of researchers has published a series of papers in the journal Astronomy & Astrophysics reporting initial results of their work, including detailed studies of several individual objects. Observations continue and more results will be published later.

The survey detected telltale tracers of the early stages of massive star formation, including compact regions of hydrogen gas ionized by the powerful radiation from young stars, and radio emission from methanol (wood alcohol) molecules that can pinpoint the location of very young stars still deeply shrouded by the clouds of gas and dust in which they are forming.

The survey also found many new remnants of supernova explosions — the dramatic deaths of massive stars. Previous studies had found fewer than a third of the expected number of supernova remnants in the Milky Way. In the region it studied, GLOSTAR more than doubled the number found using the VLA data alone, with more expected to appear in the Effelsberg data.

“This is an important step to solve this longstanding mystery of the missing supernova remnants,” said Rohit Dokara, a Ph.D student at the Max Planck Institute for Radioastronomy (MPIfR) and lead author on a paper about the remnants.

The GLOSTAR team combined data from the VLA and the Effelsberg telescope to obtain a complete view of the region they studied. The multi-antenna VLA — an interferometer — combines the signals from widely-separated antennas to make images with very high resolution that show small details. However, such a system often cannot also detect large-scale structures. The 100-meter-diameter Effelsberg telescope provided the data on structures larger than those the VLA could detect, making the image complete.

“This clearly demonstrates that the Effelberg telescope is still very crucial, even after 50 years of operation,” said Andreas Brunthaler of MPIfR, project leader and first author of the survey’s overview paper.

Visible light is strongly absorbed by dust, which radio waves can readily penetrate. Radio telescopes are essential to revealing the dust-shrouded regions in which young stars form.

The results from GLOSTAR, combined with other radio and infrared surveys, “offers astronomers a nearly complete census of massive star-forming clusters at various stages of formation, and this will have lasting value for future studies,” said team member William Cotton, of the National Radio Astronomy Observatory (NRAO), who is an expert in combining interferometer and single-telescope data.

“GLOSTAR is the first map of the Galactic Plane at radio wavelengths that detects many of the important star formation tracers at high spatial resolution. The detection of atomic and molecular spectral lines is critical to determine the location of star formation and to better understand the structure of the Galaxy,” said Dana Balser, also of NRAO.

The initiator of GLOSTAR, the MPIfR’s Karl Menten, added, “It’s great to see the beautiful science resulting from two of our favorite radio telescopes joining forces.”

The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

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Dave Finley, Public Information Officer
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dfinley@nrao.edu

Link to Scientific Papers

Source: National Radio Astronomy Observatory (NRAO)/News

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Astronomers make first clear detection of a moon-forming disc around an exoplanet

PR Image eso2111a

Wide and close-up views of a moon-forming disc as seen with ALMA

 

PR Image eso2111b

The PDS 70 system as seen with ALMA 

 

PR Image eso2111c

Moon-forming disc around the PDS 70c exoplanet as seen with ALMA 

 

PR Image eso2111d

The dwarf star PDS 70 in the constellation Centaurus 

 

PR Image eso2111e

Widefield image of the sky around PDS 70

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Videos

PR Video eso2111a

Peeking at a Distant Moon-Forming Disc (ESOcast Light 240) 

 

PR Video eso2111b

Artist’s animation of the PDS70 system 

 

PR Video eso2111c

Zooming in on the PDS 70 system

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Using the Atacama Large Millimetre/submillimeter Array (ALMA), in which the European Southern Observatory (ESO) is a partner, astronomers have unambiguously detected the presence of a disc around a planet outside our Solar System for the first time. The observations will shed new light on how moons and planets form in young stellar systems.

“Our work presents a clear detection of a disc in which satellites could be forming,” says Myriam Benisty, a researcher at the University of Grenoble, France, and at the University of Chile, who led the new research published today in The Astrophysical Journal Letters. “Our ALMA observations were obtained at such exquisite resolution that we could clearly identify that the disc is associated with the planet and we are able to constrain its size for the first time,” she adds.

The disc in question, called a circumplanetary disc, surrounds the exoplanet PDS 70c, one of two giant, Jupiter-like planets orbiting a star nearly 400 light-years away. Astronomers had found hints of a “moon-forming” disc around this exoplanet before but, since they could not clearly tell the disc apart from its surrounding environment, they could not confirm its detection — until now.

In addition, with the help of ALMA, Benisty and her team found that the disc has about the same diameter as the distance from our Sun to the Earth and enough mass to form up to three satellites the size of the Moon.

But the results are not only key to finding out how moons arise. “These new observations are also extremely important to prove theories of planet formation that could not be tested until now,” says Jaehan Bae, a researcher from the Earth and Planets Laboratory of the Carnegie Institution for Science, USA, and author on the study.

Planets form in dusty discs around young stars, carving out cavities as they gobble up material from this circumstellar disc to grow. In this process, a planet can acquire its own circumplanetary disc, which contributes to the growth of the planet by regulating the amount of material falling onto it. At the same time, the gas and dust in the circumplanetary disc can come together into progressively larger bodies through multiple collisions, ultimately leading to the birth of moons.

But astronomers do not yet fully understand the details of these processes. “In short, it is still unclear when, where, and how planets and moons form,” explains ESO Research Fellow Stefano Facchini, also involved in the research. 

“More than 4000 exoplanets have been found until now, but all of them were detected in mature systems. PDS 70b and PDS 70c, which form a system reminiscent of the Jupiter-Saturn pair, are the only two exoplanets detected so far that are still in the process of being formed,” explains Miriam Keppler, researcher at the Max Planck Institute for Astronomy in Germany and one of the co-authors of the study [1].

“This system therefore offers us a unique opportunity to observe and study the processes of planet and satellite formation,” Facchini adds. 

PDS 70b and PDS 70c, the two planets making up the system, were first discovered using ESO’s Very Large Telescope (VLT) in 2018 and 2019 respectively, and their unique nature means they have been observed with other telescopes and instruments many times since [2].

The latest high resolution ALMA observations have now allowed astronomers to gain further insights into the system. In addition to confirming the detection of the circumplanetary disc around PDS 70c and studying its size and mass, they found that PDS 70b does not show clear evidence of such a disc, indicating that it was starved of dust material from its birth environment by PDS 70c.

An even deeper understanding of the planetary system will be achieved with ESO’s Extremely Large Telescope (ELT), currently under construction on Cerro Armazones in the Chilean Atacama desert. “The ELT will be key for this research since, with its much higher resolution, we will be able to map the system in great detail,” says co-author Richard Teague, a researcher at the Center for Astrophysics | Harvard & Smithsonian, USA. In particular, by using the ELT’s Mid-infrared ELT Imager and Spectrograph (METIS), the team will be able to look at the gas motions surrounding PDS 70c to get a full 3D picture of the system.       .

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Notes

[1] Despite the similarity with the Jupiter-Saturn pair, note that the disc around PDS 70c is about 500 times larger than Saturn's rings.

[2] PDS 70b was discovered using the Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) instrument, while PDS 70c was found using the VLT’s Multi Unit Spectroscopic Explorer (MUSE). The two-planet system has been investigated using the X-shooter instrument too, also installed on ESO’s VLT.

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More Information

This research was presented in the paper “A Circumplanetary Disk Around PDS 70c” to appear in The Astrophysical Journal Letters.

The team is composed of Myriam Benisty (Unidad Mixta Internacional Franco-Chilena de Astronomía, CNRS, Departamento de Astronomía, Universidad de Chile, Santiago de Chile, Chile and Université Grenoble Alpes, CNRS, Grenoble, France [UGA]), Jaehan Bae (Earth and Planets Laboratory, Carnegie Institution for Science, Washington DC, USA), Stefano Facchini (European Southern Observatory, Garching bei München, Germany), Miriam Keppler (Max Planck Institute for Astronomy, Heidelberg, Germany [MPIA]), Richard Teague (Center for Astrophysics | Harvard & Smithsonian, Cambridge, MA, USA [CfA]), Andrea Isella (Department of Physics and Astronomy, Rice University, Houston, TX, USA), Nicolas T. Kurtovic (MPIA), Laura M. Perez (Departamento de Astronomía, Universidad de Chile, Santiago de Chile, Chile [UCHILE]), Anibal Sierra (UCHILE), Sean M. Andrews (CfA), John Carpenter (Joint ALMA Observatory, Santiago de Chile, Chile), Ian Czekala (Department of Astronomy and Astrophysics, Pennsylvania State University, PA, USA, Center for Exoplanets and Habitable Worlds, Davey Laboratory, Pennsylvania State University, PA, USA, Center for Astrostatistics, Davey Laboratory, Pennsylvania State University, PA, USA and Institute for Computational & Data Sciences, Pennsylvania State University, PA, USA), Carsten Dominik (Anton Pannekoek Institute for Astronomy, University of Amsterdam, The Netherlands), Thomas Henning (MPIA), Francois Menard (UGA), Paola Pinilla (MPIA and Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, UK) and Alice Zurlo (Núcleo de Astronomía, Facultad de Ingeniería y Ciencias, Universidad Diego Portales, Santiago de Chile, Chile and Escuela de Ingeniería Industrial, Facultad de Ingeniería y Ciencias, Universidad Diego Portales, Santiago de Chile, Chile).

ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It has 16 Member States: Austria, Belgium, the Czech Republic, Denmark, France, Finland, Germany, Ireland, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile and with Australia as a Strategic Partner. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope and its world-leading Very Large Telescope Interferometer as well as two survey telescopes, VISTA working in the infrared and the visible-light VLT Survey Telescope. Also at Paranal ESO will host and operate the Cherenkov Telescope Array South, the world’s largest and most sensitive gamma-ray observatory. ESO is also a major partner in two facilities on Chajnantor, APEX and ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre Extremely Large Telescope, the ELT, which will become “the world’s biggest eye on the sky”. The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of ESO, the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the Ministry of Science and Technology (MOST) and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI). ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

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Contacts

Myriam Benisty
Universidad de Chile and Université Grenoble Alpes
Santiago de Chile, Chile
Email: myriam.benisty@univ-grenoble-alpes.fr

Jaehan Bae
Earth and Planets Laboratory, Carnegie Institution for Science
Washington DC, USA
Email: jbae@carnegiescience.edu

Stefano Facchini
European Southern Observatory
Garching bei München, Germany
Email: stefano.facchini@eso.org

Miriam Keppler
Max Planck Institute for Astronomy
Heidelberg, Germany
Email: keppler@mpia.de

Richard Teague
Center for Astrophysics | Harvard & Smithsonian
Cambridge, MA, USA
Email: richard.d.teague@cfa.harvard.edu

Bárbara Ferreira
ESO Media Manager
Garching bei München, Germany
Cell: +49 151 241 664 00
Email: press@eso.org

Source:ESO/News

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