NASA's Webb Reveals Intricate Layers of Interstellar Dust, Gas

Cassiopeia A Light Echoes (NIRCam Images)
Credits/Image: NASA, ESA, CSA, STScI, Jacob Jencson (Caltech/IPAC)

Cassiopeia A Light Echoes (Spitzer Context)
Credits/Image: NASA, ESA, CSA, STScI

Individual Image Credits: 1. Spitzer Image: NASA/JPL-Caltech/Y. Kim (Univ. of Arizona/Univ. of Chicago); 2. Cassiopeia A Inset: NASA, ESA, CSA, STScI, Danny Milisavljevic (Purdue University), Ilse De Looze (Ghent University), Tea Temim (Princeton University); 3. Light Echoes Inset: NASA, ESA, CSA, STScI, J. Jencson (Caltech/IPAC)

Cassiopeia A Light Echoes (Compass Image)
Credits/Image: NASA, ESA, CSA, STScI, Jacob Jencson (Caltech/IPAC)

Cassiopeia A Light Echoes Time-lapse
Credits/Video: NASA, ESA, CSA, STScI, Jacob Jencson (Caltech/IPAC), Joseph DePasquale (STScI)

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Once upon a time, the core of a massive star collapsed, creating a shockwave that blasted outward, ripping the star apart as it went. When the shockwave reached the star’s surface, it punched through, generating a brief, intense pulse of X-rays and ultraviolet light that traveled outward into the surrounding space. About 350 years later, that pulse of light has reached interstellar material, illuminating it, warming it, and causing it to glow in infrared light.

NASA’s James Webb Space Telescope has observed that infrared glow, revealing fine details resembling the knots and whorls of wood grain. These observations are allowing astronomers to map the true 3D structure of this interstellar dust and gas (known as the interstellar medium) for the first time.

“We were pretty shocked to see this level of detail,” said Jacob Jencson of Caltech/IPAC in Pasadena, principal investigator of the science program.

“We see layers like an onion,” added Josh Peek of the Space Telescope Science Institute in Baltimore, a member of the science team. “We think every dense, dusty region that we see, and most of the ones we don’t see, look like this on the inside. We just have never been able to look inside them before.”

The team is presenting their findings in a press conference at the 245th meeting of the American Astronomical Society in National Harbor, Maryland.

“Even as a star dies, its light endures—echoing across the cosmos. It’s been an extraordinary three years since we launched NASA’s James Webb Space Telescope. Every image, every discovery, shows a portrait not only of the majesty of the universe but the power of the NASA team and the promise of international partnerships. This groundbreaking mission, NASA’s largest international space science collaboration, is a true testament to NASA’s ingenuity, teamwork, and pursuit of excellence,” said NASA Administrator Bill Nelson. “What a privilege it has been to oversee this monumental effort, shaped by the tireless dedication of thousands of scientists and engineers around the globe. This latest image beautifully captures the lasting legacy of Webb—a keyhole into the past and a mission that will inspire generations to come.”

Taking a CT Scan

The images from Webb’s NIRCam (Near-Infrared Camera) highlight a phenomenon known as a light echo. A light echo is created when a star explodes or erupts, flashing light into surrounding clumps of dust and causing them to shine in an ever-expanding pattern. Light echoes at visible wavelengths (such as those seen around the star V838 Monocerotis ) are due to light reflecting off of interstellar material. In contrast, light echoes at infrared wavelengths are caused when the dust is warmed by energetic radiation and then glows.

The researchers targeted a light echo that had previously been observed by NASA’s retired Spitzer Space Telescope. It is one of dozens of light echoes seen near the Cassiopeia A supernova remnant – the remains of the star that exploded. The light echo is coming from unrelated material that is behind Cassiopeia A, not material that was ejected when the star exploded.

The most obvious features in the Webb images are tightly packed sheets. These filaments show structures on remarkably small scales of about 400 astronomical units, or less than one-hundredth of a light-year. (An astronomical unit, or AU, is the average Earth-Sun distance. Neptune’s orbit is 60 AU in diameter.)

“We did not know that the interstellar medium had structures on that small of a scale, let alone that it was sheet-like,” said Peek.

These sheet-like structures may be influenced by interstellar magnetic fields. The images also show dense, tightly wound regions that resemble knots in wood grain. These may represent magnetic “islands” embedded within the more streamlined magnetic fields that suffuse the interstellar medium.

“This is the astronomical equivalent of a medical CT scan,” explained Armin Rest of the Space Telescope Science Institute, a member of the science team. “We have three slices taken at three different times, which will allow us to study the true 3D structure. It will completely change the way we study the interstellar medium.”

Future Work

The team’s science program also includes spectroscopic observations using Webb’s MIRI (Mid-Infrared Instrument). They plan to target the light echo multiple times, weeks or months apart, to observe how it evolves as the light echo passes by.

“We can observe the same patch of dust before, during, and after it’s illuminated by the echo and try to look for any changes in the compositions or states of the molecules, including whether some molecules or even the smallest dust grains are destroyed,” said Jencson.

Infrared light echoes are also extremely rare, since they require a specific type of supernova explosion with a short pulse of energetic radiation. NASA’s upcoming Nancy Grace Roman Space Telescope will conduct a survey of the galactic plane that may find evidence of additional infrared light echoes for Webb to study in detail.

The James Webb Space Telescope is the world's premier space science observatory. Webb is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and CSA (Canadian Space Agency).

Source: NASA's James Webb Space Telescope/News

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Science: Jacob Jencson (Caltech/IPAC

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Cassiopeia A: NASA Telescopes Chase Down "Green Monster" in Star's Debris

Cassiopeia A
Credit: X-ray: NASA/CXC/SAO; Optical: NASA/ESA/STScI;
IR: NASA/ESA/CSA/STScI/Milisavljevic et al., NASA/JPL/CalTech;
Image Processing: NASA/CXC/SAO/J. Schmidt and K. Arcand

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Tour: New Stellar Danger to Planets Identified by NASA's Chandra (Video YouTube)

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For the first time astronomers have combined data from NASA’s Chandra X-ray Observatory and James Webb Space Telescope to study the well-known supernova remnant Cassiopeia A (Cas A). As described in our latest press release, this work has helped explain an unusual structure in the debris from the destroyed star called the “Green Monster”, first discovered in Webb data in April 2023. The research has also uncovered new details about the explosion that created Cas A about 340 years ago, from Earth’s perspective.

A new composite image contains X-rays from Chandra (blue), infrared data from Webb (red, green, blue), and optical data from Hubble (red and white). The outer parts of the image also include infrared data from NASA’s Spitzer Space Telescope (red, green and blue). The outline of the Green Monster can be seen by mousing over the image.

The Chandra data reveals hot gas, mostly from supernova debris from the destroyed star, including elements like silicon and iron. In the outer parts of Cas A the expanding blast wave is striking surrounding gas that was ejected by the star before the explosion. The X-rays are produced by energetic electrons spiraling around magnetic field lines in the blast wave. These electrons light up as thin arcs in the outer regions of Cas A, and in parts of the interior. Webb highlights infrared emission from dust that is warmed up because it is embedded in the hot gas seen by Chandra, and from much cooler supernova debris. The Hubble data shows stars in the field.

A separate graphic shows a color Chandra image, where red shows iron and magnesium at low X-ray energies, green shows silicon at intermediate X-ray energies and blue shows the highest energy X-rays, from electrons spiraling around magnetic field lines. An outline of the Green Monster, plus the locations of the blast wave, and of debris rich in silicon and iron are labeled.

Chandra Image of Cassiopeia A, Labeled
Credit: X-ray: NASA/CXC/SAO

Detailed analysis by the researchers found that filaments in the outer part of Cas A, from the blast wave, closely matched the X-ray properties of the Green Monster, including less iron and silicon than in the supernova debris. This interpretation is apparent from the color Chandra image, which shows that the colors inside the Green Monster’s outline best match with the colors of the blast wave rather than the debris with iron and silicon. The authors conclude that the Green Monster was created by a blast wave from the exploded star slamming into material surrounding it, supporting earlier suggestions from the Webb data alone.

The debris from the explosion is seen by Chandra because it is heated to tens of millions of degrees by shock waves, akin to sonic booms from a supersonic plane. Webb can see some material that has not been affected by shock waves, what can be called “pristine” debris.

To learn more about the supernova explosion, the team compared the Webb view of the pristine debris with X-ray maps of radioactive elements that were created in the supernova. They used NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR) data to map radioactive titanium — still visible today — and Chandra to map where radioactive nickel was by measuring the locations of iron. Radioactive nickel decays to form iron. An additional image shows the iron-rich debris (tracing where radioactive nickel was located) in green, the radioactive titanium in blue and the pristine debris seen in orange and yellow.

Iron/Titanium/Pristine Debris Cassiopeia A, Labeled
Credit: X-ray: NASA/CXC/SAO; Image Processing: NASA/CXC/SAO/J. Schmidt and J. Major

Some filaments of pristine debris near the center of Cas A, seen with Webb, are connected to the iron seen with Chandra farther out. Radioactive titanium is seen where pristine debris is relatively weak. These comparisons suggest that radioactive material seen in X-rays has helped shape the pristine debris near the center of the remnant seen with Webb, forming cavities. The fine structures in the pristine debris were most likely formed when the star’s inner layers were violently mixed with hot, radioactive matter produced during collapse of the star’s core under gravity.

These results were presented by Dan Milisavljevic from Purdue University at the 243rd meeting of the American Astronomical Society in New Orleans. They are described in more detail in two papers submitted to Astrophysical Journal Letters, one led by Milisavljevic focused on the Webb results (preprint here) and the other led by Jacco Vink of the University of Amsterdam focused on the Chandra results (preprint here). The co-authors of Vink’s paper are Manan Agarwal (University of Amsterdam, the Netherlands), Patrick Slane (Center for Astrophysics | Harvard & Smithsonian - CfA), Ilse De Looze (Ghent University, Belgium), Dan Milisavljevic, Daniel Patnaude (CfA), Paul Plucinsky (CfA), and Tea Temin (Princeton University). Related papers by other members of the research team are also in preparation.

The Smithsonian Astrophysical Observatory's Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.

The James Webb Space Telescope is the world's premier space science observatory. Webb is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and the Canadian Space Agency.

A Small Explorer mission led by Caltech and managed by JPL for NASA’s Science Mission Directorate in Washington, NuSTAR was developed in partnership with the Danish Technical University and the Italian Space Agency (ASI). The spacecraft was built by Orbital Sciences Corp. in Dulles, Virginia. NuSTAR’s mission operations center is at the University of California, Berkeley, and the official data archive is at NASA’s High Energy Astrophysics Science Archive Research Center at the agency’s Goddard Space Flight Center in Greenbelt, Maryland. ASI provides the mission’s ground station and a mirror data archive. Caltech manages JPL for NASA.

 

Quick Look: NASA Telescopes Chase Down "Green Monster" in Star's Debris

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Visual Description:

This image of Cassiopeia A resembles a disk of electric light with red clouds, glowing white streaks, red and orange flames, and an area near the center of the remnant resembling a somewhat circular region of green lightning. X-rays from Chandra are blue and reveal hot gas, mostly from supernova debris from the destroyed star, and include elements like silicon and iron. X-rays are also present as thin arcs in the outer regions of the remnant.

Infrared data from Webb is red, green, and blue. Webb highlights infrared emission from dust that is warmed up because it is embedded in the hot gas seen by Chandra, and from much cooler supernova debris. Hubble data shows a multitude of stars that permeate the field of view.

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Fast Facts for (Cassiopeia A):

Scale: Image is about 8 arcmin (25.5 light-years) across.
Category: Supernovas & Supernova Remnants
Coordinates (J2000): RA 23h 23m 26.7s | Dec +58° 49´ 03.00"
Constellation: Cassiopeia
Observation Dates: Nine observations in 2004: Feb 8, Apr 14, 18, 20, 22, 25 28, May 1, 5
Observation Time: 277 hours 58 minutes (11 days 13 hours 58 minutes)
Obs. ID: 4634-4639, 5196, 5319-5320
Instrument: ACIS
Also Known As: Cas A
References: Vink, J. et al. 2024, ApJ, submitted. Milisavljevic, D. et al. 2024, ApJ, submitted.
Color Code: X-ray: blue; Optical: red, white; Infrared: red, green, blue
Distance Estimate: About 11,000 light-years

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The Crab Nebula Seen in New Light by NASA's Webb

Crab Nebula (NIRCam and MIRI Image)
Credits> Image: NASA, ESA, CSA, STScI, Tea Temim (Princeton University)

Crab Nebula (Webb and Hubble Comparison)
Credits: Image: NASA, ESA, CSA, STScI, Jeff Hester (ASU), Allison Loll (ASU), Tea Temim (Princeton University)

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NASA’s James Webb Space Telescope has gazed at the Crab Nebula, a supernova remnant located 6,500 light-years away in the constellation Taurus. Since the recording of this energetic event in 1054 CE by 11th-century astronomers, the Crab Nebula has continued to draw attention and additional study as scientists seek to understand the conditions, behavior, and after-effects of supernovae through thorough study of the Crab, a relatively nearby example.

Using Webb’s NIRCam (Near-Infrared Camera) and MIRI (Mid-Infrared Instrument), a team led by Tea Temim at Princeton University is searching for answers about the Crab Nebula’s origins.

“Webb’s sensitivity and spatial resolution allow us to accurately determine the composition of the ejected material, particularly the content of iron and nickel, which may reveal what type of explosion produced the Crab Nebula,” explained Temim.

At first glance, the general shape of the supernova remnant is similar to the optical wavelength image released in 2005 from NASA’s Hubble Space Telescope : In Webb’s infrared observation, a crisp, cage-like structure of fluffy gaseous filaments are shown in red-orange. However, in the central regions, emission from dust grains (yellow-white and green) is mapped out by Webb for the first time.

Additional aspects of the inner workings of the Crab Nebula become more prominent and are seen in greater detail in the infrared light captured by Webb. In particular, Webb highlights what is known as synchrotron radiation: emission produced from charged particles, like electrons, moving around magnetic field lines at relativistic speeds. The radiation appears here as milky smoke-like material throughout the majority of the Crab Nebula’s interior.

This feature is a product of the nebula’s pulsar, a rapidly rotating neutron star. The pulsar’s strong magnetic field accelerates particles to extremely high speeds and causes them to emit radiation as they wind around magnetic field lines. Though emitted across the electromagnetic spectrum, the synchrotron radiation is seen in unprecedented detail with Webb’s NIRCam instrument.

To locate the Crab Nebula’s pulsar heart, trace the wisps that follow a circular ripple-like pattern in the middle to the bright white dot in the center. Farther out from the core, follow the thin white ribbons of the radiation. The curvy wisps are closely grouped together, outlining the structure of the pulsar’s magnetic field, which sculpts and shapes the nebula.

At center left and right, the white material curves sharply inward from the filamentary dust cage’s edges and goes toward the neutron star’s location, as if the waist of the nebula is pinched. This abrupt slimming may be caused by the confinement of the supernova wind’s expansion by a belt of dense gas.

The wind produced by the pulsar heart continues to push the shell of gas and dust outward at a rapid pace. Among the remnant’s interior, yellow-white and green mottled filaments form large-scale loop-like structures, which represent areas where dust grains reside.

The search for answers about the Crab Nebula’s past continues as astronomers further analyze the Webb data and consult previous observations of the remnant taken by other telescopes . Scientists will have newer Hubble data to review within the next year or so from the telescope’s reimaging of the supernova remnant. This will mark Hubble’s first look at emission lines from the Crab Nebula in over 20 years, and will enable astronomers to more accurately compare Webb and Hubble’s findings.

Want to learn more? Through NASA’s Universe of Learning, part of NASA’s Science Activation program, explore images of the Crab Nebula from other telescopes, a 3D visualization, data sonification, and hands-on activities. These resources and more information about supernova remnants and star lifecycles can be found at NASA’s Universe of Learning.

The James Webb Space Telescope is the world’s premier space science observatory. Webb is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and the Canadian Space Agency. NASA’s Universe of Learning materials are based upon work supported by NASA under cooperative agreement award number NNX16AC65A to the Space Telescope Science Institute, working in partnership with Caltech/IPAC, Center for Astrophysics | Harvard & Smithsonian, and Jet Propulsion Laboratory.

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Abigail Major
Space Telescope Science Institute, Baltimore, Maryland

Christine Pulliam
Space Telescope Science Institute, Baltimore, Maryland

Science: Tea Temim (Princeton University)

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Source: NASA's James Webb Space Telescope/News

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Living on the Edge: Supernova Bubble Expands in New Hubble Time-Lapse Movie

Cygnus Loop
Credits: Image: NASA, ESA, Ravi Sankrit (STScI)

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Though a doomed star exploded some 20,000 years ago, its tattered remnants continue racing into space at breakneck speeds – and NASA's Hubble Space Telescope has caught the action.

The nebula, called the Cygnus Loop, forms a bubble-like shape that is about 120 light-years in diameter. The distance to its center is approximately 2,600 light-years. The entire nebula has a width of six full Moons as seen on the sky.

Astronomers used Hubble to zoom into a very small slice of the leading edge of this expanding supernova bubble, where the supernova blast wave plows into surrounding material in space. Hubble images taken from 2001 to 2020 clearly demonstrate how the remnant's shock front has expanded over time, and they used the crisp images to clock its speed.

By analyzing the shock's location, astronomers found that the shock hasn't slowed down at all in the last 20 years, and is speeding into interstellar space at over half a million miles per hour – fast enough to travel from Earth to the Moon in less than half an hour. While this seems incredibly fast, it's actually on the slow end for the speed of a supernova shock wave. Researchers were able to assemble a "movie" from Hubble images for a close-up look at how the tattered star is slamming into interstellar space.

"Hubble is the only way that we can actually watch what's happening at the edge of the bubble with such clarity," said Ravi Sankrit, an astronomer at the Space Telescope Science Institute in Baltimore, Maryland. "The Hubble images are spectacular when you look at them in detail. They're telling us about the density differences encountered by the supernova shocks as they propagate through space, and the turbulence in the regions behind these shocks."

A very close-up look at a nearly two-light-year-long section of the filaments of glowing hydrogen shows that they look like a wrinkled sheet seen from the side. "You're seeing ripples in the sheet that is being seen edge-on, so it looks like twisted ribbons of light," said William Blair of the Johns Hopkins University, Baltimore, Maryland. "Those wiggles arise as the shock wave encounters more or less dense material in the interstellar medium." The time-lapse movie over nearly two decades shows the filaments moving against the background stars but keeping their shape.

"When we pointed Hubble at the Cygnus Loop we knew that this was the leading edge of a shock front, which we wanted to study. When we got the initial picture and saw this incredible, delicate ribbon of light, well, that was a bonus. We didn't know it was going to resolve that kind of structure," said Blair.

Blair explained that the shock is moving outward from the explosion site and then it starts to encounter the interstellar medium, the tenuous regions of gas and dust in interstellar space. This is a very transitory phase in the expansion of the supernova bubble where invisible neutral hydrogen is heated to 1 million degrees Fahrenheit or more by the shock wave's passage. The gas then begins to glow as electrons are excited to higher energy states and emit photons as they cascade back to low energy states. Further behind the shock front, ionized oxygen atoms begin to cool, emitting a characteristic glow shown in blue.

The Cygnus Loop was discovered in 1784 by William Herschel, using a simple 18-inch reflecting telescope. He could have never imagined that a little over two centuries later we'd have a telescope powerful enough to zoom in on a very tiny slice of the nebula for this spectacular view.

The Hubble Space Telescope is a project of international cooperation between NASA and ESA. NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, in Washington, D.C.

Source: HubbleSite/News

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Release: NASA, ESA, Ravi Sankrit (STScI)

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Space Telescope Science Institute, Baltimore, Maryland

William Blair
Johns Hopkins University, Baltimore, Maryland

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Related Links and Documents

Science Paper: The science paper by R. Sankrit et al., PDF (1.81 MB)

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Webb Reveals Never-Before-Seen Details in Cassiopeia A

Cassiopeia A (MIRI Image)

< div style="text-align: justify;"> Credits: Image: NASA, ESA, CSA, Danny Milisavljevic (Purdue University), Tea Temim (Princeton University), Ilse De Looze (UGent). Image Processing: Joseph DePasquale (STScI)

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The explosion of a star is a dramatic event, but the remains the star leaves behind can be even more dramatic. A new mid-infrared image from NASA’s James Webb Space Telescope provides one stunning example. It shows the supernova remnant Cassiopeia A (Cas A), created by a stellar explosion 340 years ago. Cas A is the youngest known remnant from an exploding, massive star in our galaxy, which makes it a unique opportunity to learn more about how such supernovae occur.

“Cas A represents our best opportunity to look at the debris field of an exploded star and run a kind of stellar autopsy to understand what type of star was there beforehand and how that star exploded,” said Danny Milisavljevic of Purdue University in West Lafayette, Indiana, principal investigator of the Webb program that captured these observations.

“Compared to previous infrared images, we see incredible detail that we haven't been able to access before,” added Tea Temim of Princeton University in Princeton, New Jersey, a co-investigator on the program.

Cassiopeia A is a prototypical supernova remnant that has been widely studied by a number of ground-based and space-based observatories, including NASA’s Chandra X-ray Observatory . The multi-wavelength observations can be combined to provide scientists with a more comprehensive understanding of the remnant.

Dissecting the Image

The striking colors of the new Cas A image, in which infrared light is translated into visible-light wavelengths, hold a wealth of scientific information the team is just beginning to tease out. On the bubble’s exterior, particularly at the top and left, lie curtains of material appearing orange and red due to emission from warm dust. This marks where ejected material from the exploded star is ramming into surrounding circumstellar gas and dust.

Interior to this outer shell lie mottled filaments of bright pink studded with clumps and knots. This represents material from the star itself, which is shining due to a mix of various heavy elements, such as oxygen, argon, and neon, as well as dust emission.

“We’re still trying to disentangle all these sources of emission,” said Ilse De Looze of Ghent University in Belgium, another co-investigator on the program.

The stellar material can also be seen as fainter wisps near the cavity’s interior.

Perhaps most prominently, a loop represented in green extends across the right side of the central cavity. “We’ve nicknamed it the Green Monster in honor of Fenway Park in Boston. If you look closely, you’ll notice that it’s pockmarked with what look like mini-bubbles,” said Milisavljevic. “The shape and complexity are unexpected and challenging to understand.”

Origins of Cosmic Dust – and Us

Among the science questions that Cas A may help answer is: Where does cosmic dust come from? Observations have found that even very young galaxies in the early universe are suffused with massive quantities of dust. It’s difficult to explain the origins of this dust without invoking supernovae, which spew large quantities of heavy elements (the building blocks of dust) across space.

However, existing observations of supernovae have been unable to conclusively explain the amount of dust we see in those early galaxies. By studying Cas A with Webb, astronomers hope to gain a better understanding of its dust content, which can help inform our understanding of where the building blocks of planets and ourselves are created.

“In Cas A, we can spatially resolve regions that have different gas compositions and look at what types of dust were formed in those regions,” explained Temim.

Supernovae like the one that formed Cas A are crucial for life as we know it. They spread elements like the calcium we find in our bones and the iron in our blood across interstellar space, seeding new generations of stars and planets.

“By understanding the process of exploding stars, we’re reading our own origin story,” said Milisavljevic. “I’m going to spend the rest of my career trying to understand what’s in this data set.”

The Cas A remnant spans about 10 light-years and is located 11,000 light-years away in the constellation Cassiopeia.

The James Webb Space Telescope is the world’s premier space science observatory. Webb will solve mysteries in our solar system, look beyond to distant worlds around other stars, and probe the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and the Canadian Space Agency.

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Source: NASA's James Webb Space Telescope/News

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Hubble Reveals Surviving Companion Star in Aftermath of Supernova

Supernova and Remnant Star Illustration
Credits: Artwork: NASA, ESA, Leah Hustak (STScI)

Evolution Scenario for a Stripped Envelope Supernova Illustration
Credits: Illustration: NASA, ESA, Leah Hustak (STScI)

SN 2013ge in NGC 3287
Credits: Science: NASA, ESA, Ori Fox (STScI)
Image Processing: Joseph DePasquale (STScI)

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NASA's Hubble Space Telescope has uncovered a witness at the scene of a star's explosive death: a companion star previously hidden in the glare of its partner's supernova. The discovery is a first for a particular type of supernova—one in which the star was stripped of its entire outer gas envelope before exploding.

The finding provides crucial insight into the binary nature of massive stars, as well as the potential prequel to the ultimate merger of the companion stars that would rattle across the universe as gravitational waves, ripples in the fabric of spacetime itself.

Astronomers detect the signature of various elements in supernova explosions. These elements are layered like an onion pre-supernova. Hydrogen is found in the outermost layer of a star, and if no hydrogen is detected in the aftermath of the supernova, that means it was stripped away before the explosion occurred.

The cause of the hydrogen loss had been a mystery, and astronomers have been using Hubble to search for clues and test theories to explain these stripped supernovae. The new Hubble observations provide the best evidence yet to support the theory that an unseen companion star siphons off the gas envelope from its partner star before it explodes.

"This was the moment we had been waiting for, finally seeing the evidence for a binary system progenitor of a fully stripped supernova," said astronomer Ori Fox of the Space Telescope Science Institute in Baltimore, Maryland, lead investigator on the Hubble research program. "The goal is to move this area of study from theory to working with data and seeing what these systems really look like."

Fox's team used Hubble's Wide Field Camera 3 to study the region of supernova (SN) 2013ge in ultraviolet light, as well as previous Hubble observations in the Barbara A. Mikulski Archive for Space Telescopes (MAST). Astronomers saw the light of the supernova fading over time from 2016 to 2020—but another nearby source of ultraviolet light at the same position maintained its brightness. This underlying source of ultraviolet emission is what the team proposes is the surviving binary companion to SN 2013ge.

Two by two?

Previously, scientists theorized that a massive progenitor star's strong winds could blow away its hydrogen gas envelope, but observational evidence didn't support that. To explain the disconnect, astronomers developed theories and models in which a binary companion siphons off the hydrogen.

"In recent years many different lines of evidence have told us that stripped supernovae are likely formed in binaries, but we had yet to actually see the companion. So much of studying cosmic explosions is like forensic science—searching for clues and seeing what theories match. Thanks to Hubble, we are able to see this directly," said Maria Drout of the University of Toronto, a member of the Hubble research team.

In prior observations of SN 2013ge, Hubble saw two peaks in the ultraviolet light, rather than just the one typically seen in most supernovae. Fox said that one explanation for this double brightening was that the second peak shows when the supernova's shock wave hit a companion star, a possibility that now seems much more likely. Hubble's latest observations indicate that while the companion star was significantly jostled, including the hydrogen gas it had siphoned off its partner, it was not destroyed. Fox likens the effect to a jiggling bowl of jelly, which will eventually settle back to its original form.

While additional confirmation and similar supporting discoveries need to be found, Fox said that the implications of the discovery are still substantial, lending support to theories that the majority of massive stars form and evolve as binary systems.

One to Watch

Unlike supernovae that have a puffy shell of gas to light up, the progenitors of fully stripped-envelope supernovae have proven difficult to identify in pre-explosion images. Now that astronomers have been lucky enough to identify the surviving companion star, they can use it to work backward and determine characteristics of the star that exploded, as well as the unprecedented opportunity to watch the aftermath unfold with the survivor.

As a massive star itself, SN 2013ge's companion is also destined to undergo a supernova. Its former partner is now likely a compact object, such as a neutron star or black hole, and the companion will likely go that route as well.

The closeness of the original companion stars will determine if they stay together. If the distance is too great, the companion star will be flung out of the system to wander alone across our galaxy, a fate that could explain many seemingly solitary supernovae.

However, if the stars were close enough to each other pre-supernova, they will continue orbiting each other as black holes or neutron stars. In that case, they would eventually spiral toward each other and merge, creating gravitational waves in the process.

That is an exciting prospect for astronomers, as gravitational waves are a branch of astrophysics that has only begun to be explored. They are waves or ripples in the fabric of spacetime itself, predicted by Albert Einstein in the early 20th century. Gravitational waves were first directly observed by the Laser Interferometer Gravitational-Wave Observatory (LIGO).

"With the surviving companion of SN 2013ge, we could potentially be seeing the prequel to a gravitational wave event, although such an event would still be about a billion years in the future," Fox said.

Fox and his collaborators will be working with Hubble to build up a larger sample of surviving companion stars to other supernovae, in effect giving SN 2013ge some company again.

"There is great potential beyond just understanding the supernova itself. Since we now know most massive stars in the universe form in binary pairs, observations of surviving companion stars are necessary to help understand the details behind binary formation, material-swapping, and co-evolutionary development. It's an exciting time to be studying the stars," Fox said.

"Understanding the lifecycle of massive stars is particularly important to us because all heavy elements are forged in their cores and through their supernovae. Those elements make up much of the observable universe, including life as we know it," added co-author Alex Filippenko of the University of California at Berkeley.

The results are published in The Astrophysical Journal Letters.

The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy in Washington, D.C.

Credits:

Media Contact:

Leah Ramsay
Space Telescope Science Institute, Baltimore, Maryland

Ray Villard
Space Telescope Science Institute, Baltimore, Maryland

Science Contact:

Ori Fox
Space Telescope Science Institute, Baltimore, Maryland

Permissions: Content Use Policy

Contact Us: Direct inquiries to the News Team.

Related Links and Documents:

• Science Paper: The science paper by O. Fox et al., PDF (609.39 KB)
• NASA's Hubble Portal

Source:HubbleSite/News

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Supernova simulations reveal how stellar explosions shape debris clouds

Figure 1: A supernova creates a cloud of debris that bears an imprint of the explosion. In this visualization of the simulation data, one quarter of the remnant’s outer shell has been removed to reveal the clumps of matter within (colors denote different materials). Credit: Reproduced from Ref. 1 by permission of the AAS.

Gilles Ferrand and co-workers have used computer simulations to explore how ignition and combustion processes influence the debris from supernova explosions.© 2021 RIKEN

Ignition and combustion processes leave their imprint on supernova remnants

Astronomers are now in a better position to interpret observations of supernova remnants thanks to computer simulations of these cataclysmic events by RIKEN astrophysicists¹.

When certain types of stars die, they go out in a blaze of glory—an incredibly powerful explosion known as a supernova. One of the most common forms of supernova, type Ia, starts with a dense white dwarf star that has burned up its hydrogen fuel. Matter flowing from a companion star can jump-start a runaway nuclear fusion reaction in the dwarf, triggering a massive conflagration that creates many of the heavier elements in the Universe. These are hurled outward in a luminous cloud known as a remnant, which bears an imprint of the explosion.

Gilles Ferrand of the RIKEN Astrophysical Big Bang Laboratory and colleagues in Japan and Germany have been developing three-dimensional computer simulations that recreate supernovae. Their simulations involve two steps: the first one models the supernova explosion itself, while the second one uses that as the input for a model of the supernova remnant. “Our goal is to explore how different explosion conditions produce remnants with characteristic shapes and compositions, similar to those we observe in our Galaxy,” explains Ferrand.

The team’s latest simulations focus on two aspects of supernovae: how the explosion ignites inside a white dwarf, and how combustion rips through the star. Ignition can start at just a few places inside the white dwarf, or it can be triggered at many points simultaneously. Meanwhile, the combustion might be a deflagration—a turbulent fire that moves slower than the local speed of sound—or it may involve deflagration followed by supersonic detonation.

By putting these options together in different ways, the researchers produced four models of supernova remnant. “Each model has its distinctive properties,” says Ferrand. For example, a supernova with few ignition points and a deflagration explosion produced a remnant with a symmetric shell that was offset from the center of the explosion. In contrast, a simulation involving few ignition points and a detonation produced a remnant in which half of the outer shell was twice as thick as the other half. Remnants from the deflagration simulations also featured unexpected ‘seams’ of denser material.

These results suggest that the best time to see a supernova’s imprint on its remnant is within roughly 100–300 years after the explosion. This imprint is visible for longer in supernovae with fewer ignition points, and all the remnants in the simulations became spherical overall within 500 years. These results will guide astronomers as they interpret observations of supernova remnants.

Related Contents:

• Supernova remnants used to probe how star explosion took shape
• Computer simulation probes origins of type Ia supernovae
• How a star turns inside out

Reference:

1. Ferrand, G., Warren, D. C., Ono, M., Nagataki, S., Röpke, F. K., Seitenzahl, I. R., Lach, F., Iwasaki, H. & Sato, T. From supernova to supernova remnant: Comparison of thermonuclear explosion models. The Astrophysical Journal 906, 93 (2021). doi: 10.3847/1538-4357/abc951

Source:  Riken/News

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Our deepest view of the X-ray sky

The energetic universe as seen with the eROSITA X-ray telescope. The first eROSITA all-sky survey was conducted over a period of six months by letting the telescope rotate continuously, thus providing a uniform exposure of about 150-200 seconds over most of the sky, with the ecliptic poles being visited more deeply. As eROSITA scans the sky, the energy of the collected photons is measured with an accuracy ranging from 2% - 6%. To generate this image, in which the whole sky is projected onto an ellipse (so-called Aitoff projection) with the centre of the Milky Way in the middle and the body of the Galaxy running horizontally, photons have been colour-coded according to their energy (red for energies 0.3-0.6 keV, green for 0.6-1 keV, blue for 1-2.3 keV). The original image, with a resolution of about 10”, and a corresponding dynamic range of more than one billion, is then smoothed (with a 10’ FWHM Gaussian) in order to generate the above picture.The red diffuse glow away from the galactic plane is the emission of the hot gas in the vicinity of the solar system (the Local Bubble). Along the plane itself, dust and gas absorb the lowest energy X-ray photons, so that only high-energy emitting sources can be seen, and their colour appears blue in the image. The hotter gas close to the galactic centre, shown in green and yellow, carries imprinted the history of the most energetic processes in the life of the Milky Way, such as supernova explosions, driving fountains of gas out of the plane, and, possibly, past outburst from the now dormant supermassive black hole in the centre of the galaxy. Piercing through this turbulent, hot diffuse medium, are hundreds of thousands of X-ray sources, which appear mostly white in the image, and uniformly distributed over the sky. Among them, distant active galactic nuclei (including a few emitting at a time when the Universe was less than one tenth of its current age) are visible as point sources, while clusters of galaxies reveal themselves as extended X-ray nebulosities. In total, about one million X-ray sources have been detected in the eROSITA all-sky image, a treasure trove that will keep the teams busy for the coming years. Credit: Jeremy Sanders, Hermann Brunner and the eSASS team (MPE); Eugene Churazov, Marat Gilfanov (on behalf of IKI). Additional Images

The eROSITA telescope has provided a new, sharp view of hot and energetic processes across the Universe

Over the course of 182 days, the eROSITA X-ray telescope onboard SRG has completed its first full sweep of the sky. This new map of the hot, energetic universe contains more than one million objects, roughly doubling the number of known X-ray sources discovered over the 60-year history of X-ray astronomy. Most of the new sources are active galactic nuclei at cosmological distances, marking the growth of gigantic black holes over cosmic time. Clusters of galaxies in the new map will be used to track the growth of cosmic structures and constrain cosmological parameters. Closer to home, stars with hot coronae, binaries and supernova remnants dot our Galaxy, and we now have a complete map of the hot baryons in the Milky Way, something that can only be achieved with the 360-degree view provided by the eROSITA survey.

A million X-ray sources revealing the nature of the hot universe – this is the impressive harvest of the first scan of the entire sky with the eROSITA telescope onboard SRG. “This all-sky image completely changes the way we look at the energetic universe,” says Peter Predehl, the Principal Investigator of eROSITA at the Max Planck Institute for Extraterrestrial Physics (MPE). “We see such a wealth of detail - the beauty of the images is really stunning.”

This first complete sky image from eROSITA is about 4 times deeper than the previous all-sky survey by the ROSAT telescope 30 years ago, and has yielded around 10 times more sources: about as many as have been discovered by all past X-ray telescopes combined. And while most classes of astronomical objects emit in X-rays, the hot and energetic Universe looks quite different to the one seen by optical or radio telescopes. Looking outside the body of our Galaxy, most of the eROSITA sources are active galactic nuclei, accreting supermassive black holes at cosmological distances, interspersed with clusters of galaxies, which appear as extended X-ray haloes shining thanks to the hot gas confined by their huge concentrations of dark matter. The all-sky image reveals in exquisite detail the structure of the hot gas in the Milky Way itself, and the circum-galactic medium, which surrounds it, whose properties are key to understanding the formation history of our Galaxy. The eROSITA X-ray map also reveals stars with strong, magnetically active hot coronae, X-ray binary stars containing neutron stars, black holes or white dwarves, and spectacular supernova remnants in our own and other nearby galaxies such as the Magellanic clouds.

Due to its size and close distance to Earth, the "Vela supernova remnant" which is shown in this picture is one of the most prominent objects in the X-ray sky. The Vela supernova exploded about 12000 years ago at a distance of 800 light-years and overlaps with at least two other supernova remnants, Vela Junior (in the picture seen as bluish ring at the bottom left) and Puppis-A (top right). Vela Junior was discovered just 20 years ago, although this object is so close to Earth that remains of this explosion were found in polar ice cores. All three supernova explosions produced both the X-ray-bright supernova remnants and neutron stars, which shine as intense X-ray point sources near the centres of the remnants. The quality of the new eROSITA data of this "stellar cemetery" will give astronomers many exciting new insights into the physical processes operating in the hot supernova plasma as well as for exploring the exotic neutron stars. Credit: Peter Predehl, Werner Becker (MPE), Davide Mella

We were all eagerly awaiting the first all-sky map from eROSITA,” says Mara Salvato, the scientist at MPE who leads the effort to combine eROSITA observations with other telescopes across the electromagnetic spectrum. “Large sky areas have already been covered at many other wavelengths, and now we have the X-ray data to match. We need these other surveys to identify the X-ray sources and understand their nature.” The survey is also a treasure trove of rare and exotic phenomena, including numerous types of transients and variables, such as flares from compact objects, merging neutron stars, and stars being swallowed by black holes. “eROSITA often sees unexpected bursts of X-rays from the sky,” continues Salvato. “We need to alert ground-based telescopes immediately to understand what’s producing them.”  

Assembling the image has been a mammoth task. So far, the operations team has received and processed about 165 GB of data collected by eROSITA’s seven cameras. While relatively small by “big-data” standards on the ground, operating this complex instrument in space provided its own special challenges. “We check and monitor the health of the instrument on a daily basis, in cooperation with our colleagues in Moscow who operate the SRG spacecraft” explains Miriam Ramos-Ceja, a member of the eROSITA operations team at MPE. “This means we can respond quickly to any anomalies. We’ve been able to react to these immediately to keep the instrument safe, while collecting data at ~97% efficiency. It’s amazing to be able to communicate in real time with an instrument located 1.5 million kilometres away!” The data downlink occurs daily. “We perform immediate quality checks on the data”, she continues, “before it is being processed and analysed by the teams in Germany and Russia.”

While the team is now busy analysing this first all-sky map and using the images and catalogues to deepen our understanding of cosmology and high-energy astrophysical processes, the telescope continues its sweep of the X-ray sky. “The SRG Observatory is now starting its second all-sky survey, which will be completed by the end of this year“, says Rashid Sunyaev, Lead Scientist of the Russian SRG team. “Overall, during the next 3.5 years, we plan to get 7 maps similar to the one seen in this beautiful image. Their combined sensitivity will be a factor of 5 better and will be used by astrophysicists and cosmologists for decades.“

Kirpal Nandra, head of the high-energy astrophysics group at MPE, adds “With a million sources in just six months, eROSITA has already revolutionized X-ray astronomy, but this is just a taste of what’s to come. This combination of sky area and depth is transformational. We are already sampling a cosmological volume of the hot Universe much larger than has been possible before. Over the next few years, we’ll be able to probe even further, out to where the first giant cosmic structures and supermassive black holes were forming.”

The Shapley supercluster of galaxies is one of the most massive concentrations of galaxies in the local universe at a distance of about 650 million light-years (z~0.05). Each of the dozen extended structures is itself a cluster of galaxies, consisting of 100s to 1000s of individual galaxies, each denoting an intersection of filaments making up the large-scale structure in the Universe. This image spans 16 degrees across the sky (about 30 times the size of the full moon), which translates into about 180 million light-years across at the distance of the Shapley supercluster. The images on the left show a zoom of the the most massive clusters in the Shapley supercluster.  Credit: Esra Bulbul, Jeremy Sanders (MPE)

Further information:

On 11 June 2020, the eROSITA telescope completed its first survey of the entire X-ray sky. Launched on 13 July 2019 on-board the SRG spacecraft and now orbiting the second Lagrange point of the Earth-Sun-system, the telescope is in continuous scanning mode. During the first all-sky survey, each point in the sky was exposed to the eROSITA telescope for an average duration of 150-200 seconds. The regions close to the ecliptic poles, where the great circles traced by the telescope on the sky intersect, were revisited many times, accumulating exposures of up to a few hours. SRG will continue scanning the sky for three and half years more, with eROSITA performing seven more all-sky surveys in the process.

eROSITA is the primary instrument aboard SRG, a joint Russian-German science mission supported by the Russian Space Agency (Roskosmos), in the interests of the Russian Academy of Sciences represented by its Space Research Institute (IKI), and the Deutsches Zentrum für Luft- und Raumfahrt (DLR). The SRG spacecraft was built by Lavochkin Association (NPOL) and its subcontractors, and is operated by NPOL with support from the Max-Planck Institute for Extraterrestrial Physics (MPE).

The development and construction of the eROSITA X-ray instrument was led by the Max Planck Institute for Extraterrestrial Physics (MPE), with contributions from the Dr. Karl Remeis Observatory Bamberg, the University of Hamburg Observatory, the Leibniz Institute for Astrophysics Potsdam (AIP), and the Institute for Astronomy and Astrophysics of the University of Tübingen, with the support of DLR and the Max Planck Society. The Argelander Institute for Astronomy of the University of Bonn and the Ludwig-Maximilians-Universität Munich also participated in the science preparation for eROSITA.

The eROSITA data shown here were processed using the eSASS software system developed by the German eROSITA consortium.

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Contacts

Dr. Andrea Merloni
Senior Scientist
+49 (0)89 30000-3893
+49 (0)89 30000-3569

Dr. Peter Predehl
Senior Scientist
+49 (0)89 30000-3505
+4915112113639
+49 (0)89 30000-3569

Prof. Dr. Kirpal Nandra
director
+49 (0)89 30000-3401

+49 (0)89 30000-3569

Source:  Max Planck Institute for Extraterrestrial Physics

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Outback telescope captures Milky Way centre, discovers remnants of dead stars

A radio telescope in the Western Australian outback has captured a spectacular new view of the centre of the galaxy in which we live, the Milky Way.

The image from the Murchison Widefield Array (MWA) telescope shows what our galaxy would look like if human eyes could see radio waves.

This image shows a new view of the Milky Way from the Murchison Widefield Array, with the lowest frequencies in red, middle frequencies in green, and the highest frequencies in blue. Huge golden filaments indicate enormous magnetic fields, supernova remnants are visible as little spherical bubbles, and regions of massive star formation show up in blue. The supermassive black hole at the centre of our galaxy is hidden in the bright white region in the centre. Credit: Dr Natasha Hurley-Walker (ICRAR/Curtin) and the GLEAM Team.

Astrophysicist Dr Natasha Hurley-Walker, from the Curtin University node of the International Centre for Radio Astronomy Research (ICRAR), created the images using the Pawsey Supercomputing Centre in Perth.

“This new view captures low-frequency radio emission from our galaxy, looking both in fine detail and at larger structures,” she said.

“Our images are looking directly at the middle of the Milky Way, towards a region astronomers call the Galactic Centre.”

The data for the research comes from the GaLactic and Extragalactic All-sky MWA survey, or ‘GLEAM’ for short.

The survey has a resolution of two arcminutes (about the same as the human eye) and maps the sky using radio waves at frequencies between 72 and 231 MHz (FM radio is near 100 MHz).

“It’s the power of this wide frequency range that makes it possible for us to disentangle different overlapping objects as we look toward the complexity of the Galactic Centre,” Dr Hurley-Walker said.

“Essentially, different objects have different ‘radio colours’, so we can use them to work out what kind of physics is at play.”

Using the images, Dr Hurley-Walker and her colleagues discovered the remnants of 27 massive stars that exploded in supernovae at the end of their lives.

These are the 27 newly-discovered supernova remnants—the remains of stars that ended their lives in huge stellar explosions thousands to hundreds of thousands of years ago. The radio images trace the edges of the explosions as they continue their ongoing expansion into interstellar space. Some are huge, larger than the full moon, and others are small and hard to spot in the complexity of the Milky Way. Credit: Dr Natasha Hurley-Walker (ICRAR/Curtin) and the GLEAM Team.

These stars would have been eight or more times more massive than our Sun before their dramatic destruction thousands of years ago.

Younger and closer supernova remnants, or those in very dense environments, are easy to spot, and 295 are already known.

Unlike other instruments, the MWA can find those which are older, further away, or in very empty environments.

Dr Hurley-Walker said one of the newly-discovered supernova remnants lies in such an empty region of space, far out of the plane of our galaxy, and so despite being quite young, is also very faint.

“It’s the remains of a star that died less than 9,000 years ago, meaning the explosion could have been visible to Indigenous people across Australia at that time,” she said.

This 28 image photomosaic captures the arch of the milky way over the Guilderton Lighthouse in Western Australia, and the Large and Small Magellanic Clouds. The location of a supernova that would have exploded 9,000 years ago and been visible in the night sky is shown in the image. Credit: Paean Ng / Astrordinary Imaging.

An expert in cultural astronomy, Associate Professor Duane Hamacher from the University of Melbourne, said some Aboriginal traditions do describe bright new stars appearing in the sky, but we don’t know of any definitive traditions that describe this particular event.

“However, now that we know when and where this supernova appeared in the sky, we can collaborate with Indigenous elders to see if any of their traditions describe this cosmic event. If any exist, it would be extremely exciting,” he said. This is a 104 frame photomosaic capturing the Milky Way directly overhead taken at the Pinnacles Desert in Western Australia. A popular tourist location by day and incredible stargazing at night. The location of a supernova that would have exploded 9,000 years ago is shown in the image. Credit: Paean Ng / Astrordinary Imaging.

This is a 104 frame photomosaic capturing the Milky Way directly overhead taken at the Pinnacles Desert in Western Australia. A popular tourist location by day and incredible stargazing at night. The location of a supernova that would have exploded 9,000 years ago is shown in the image. Credit: Paean Ng / Astrordinary Imaging.

Dr Hurley-Walker said two of the supernova remnants discovered are quite unusual “orphans”, found in a region of sky where there are no massive stars, which means future searches across other such regions might be more successful than astronomers expected.

Other supernova remnants discovered in the research are very old, she said.

“This is really exciting for us, because it’s hard to find supernova remnants in this phase of life—they allow us to look further back in time in the Milky Way.”

The MWA telescope is a precursor to the world’s largest radio telescope, the Square Kilometre Array, which is due to be built in Australia and South Africa from 2021.

“The MWA is perfect for finding these objects, but it is limited in its sensitivity and resolution,” Dr Hurley-Walker said.

“The low-frequency part of the SKA, which will be built at the same site as the MWA, will be thousands of times more sensitive and have much better resolution, so should find the thousands of supernova remnants that formed in the last 100,000 years, even on the other side of the Milky Way.”

The new images of the Galactic Centre can be viewed via a web browser using the GLEAMoscope app or through an android device using the GLEAM app.

2017 Best Timelapse: 'GLEAM' by Dr John Goldsmith, Dr Natasha Hurley-Walker and the GLEAM Team from ICRAR on Vimeo.

Source: International Centre for Radio Astronomy Research (ICRAR)/News

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Publication:

‘New candidate radio supernova remnants detected in the GLEAM survey over 345° < l < 60°, 180° < l < 240°’, published in Publications of the Astronomical Society of Australia (PASA) on November 20th, 2019. Paper

‘Candidate radio supernova remnants observed by the GLEAM survey over 345° < l < 60°, 180° < l < 240°’, published in Publications of the Astronomical Society of Australia (PASA) on November 20th, 2019. Paper 

‘GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey II: Galactic Plane 345° < l < 67°, 180° < l < 240°’, published in Publications of the Astronomical Society of Australia (PASA) on November 20th, 2019. Paper

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More Information: 

ICRAR

The International Centre for Radio Astronomy Research (ICRAR) is a joint venture between Curtin University and The University of Western Australia with support and funding from the State Government of Western Australia. 

The Murchison Widefield Array 

The Murchison Widefield Array (MWA) is a low-frequency radio telescope and is the first of four Square Kilometre Array (SKA) precursors to be completed. A consortium of partner institutions from seven countries (Australia, USA, India, New Zealand, Canada, Japan, and China) financed the development, construction, commissioning, and operations of the facility. The MWA consortium is led by Curtin University.

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Contacts:

Dr Natasha Hurley-Walker — ICRAR / Curtin University
Ph: +61 8 9266 9178
E:Natasha.Hurley-Walker@curtin.edu.au

Pete Wheeler — Media Contact, ICRAR

Ph: +61 423 982 018

E: Pete.Wheeler@icrar.org

Lucien Wilkinson — Media Contact, Curtin University

Ph: +61 401 103 683

E: Lucien.Wilkinson@curtin.edu.au

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