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Webb probes Messier 82 (M82), an extreme starburst galaxy

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Left: Messier 82 as imaged by Hubble. Hour-glass-shaped red plumes of gas are shooting outward from above and below a bright blue, disc-shaped centre of a galaxy. This galaxy is surrounded by many white stars and set against the black background of space. Right: A section of Messier 82 as imaged by Webb. An edge-on spiral starburst galaxy with a bright white, glowing core set against the black background of space. A white band of the edge-on disc extends from lower left to upper right. Dark brown tendrils of dust are scattered thinly along this band. Many clumpy, red filaments extend vertically above and below the plane of the galaxy.

Webb probes Messier 82 (M82), an extreme starburst galaxy

Amid a galaxy teeming with new and young stars lies an intricate substructure

Left: Messier 82 as imaged by Hubble. Hour-glass-shaped red plumes of gas are shooting outward from above and below a bright blue, disc-shaped centre of a galaxy. This galaxy is surrounded by many white stars and set against the black background of space. Right: A section of Messier 82 as imaged by Webb. An edge-on spiral starburst galaxy with a bright white, glowing core set against the black background of space. A white band of the edge-on disc extends from lower left to upper right. Dark brown tendrils of dust are scattered thinly along this band. Many clumpy, red filaments extend vertically above and below the plane of the galaxy.
Annotated image of the starburst galaxy Messier 82 captured by Webb’s NIRCam (Near-Infrared Camera) instrument, with compass arrows, a scale bar, and colour key for reference.
The north and east compass arrows show the orientation of the image on the sky. Note that the relationship between north and east on the sky (as seen from below) is flipped relative to direction arrows on a map of the ground (as seen from above).
The scale bar is labelled in light-years.
This image shows invisible near-infrared wavelengths of light that have been translated into visible-light colours. The colour key shows which NIRCam filters were used when collecting the light. The colour of each filter name is the visible light colour used to represent the infrared light that passes through that filter.
Credit: NASA, ESA, CSA, STScI, A. Bolatto (UMD)

The NASA/ESA/CSA James Webb Space Telescope has set its sights on the starburst galaxy Messier 82 (M82), a small but mighty environment that features rapid star formation. By looking closer with Webb’s sensitive infrared capabilities, a team of scientists is getting to the very core of the galaxy, gaining a better understanding of how it is forming stars and how this extreme activity is affecting the galaxy as a whole.

An international team of astronomers has used the NASA/ESA/CSA James Webb Space Telescope to survey the starburst galaxy Messier 82 (M82). Located 12 million light-years away in the constellation Ursa Major, this galaxy is relatively compact in size but hosts a frenzy of star formation activity. For comparison, M82 is sprouting new stars 10 times faster than the Milky Way galaxy.

The team directed Webb’s NIRCam (Near-Infrared Camera) instrument toward the starburst galaxy’s centre, obtaining a closer look at the physical conditions that foster the formation of new stars.

“M82 has garnered a variety of observations over the years because it can be considered as the prototypical starburst galaxy,” said Alberto Bolatto, lead author of the study. “Both Spitzer and Hubble space telescopes have observed this target. With Webb’s size and resolution, we can look at this star-forming galaxy and see all of this beautiful new detail.”

Star formation continues to maintain a sense of mystery because it is shrouded by curtains of dust and gas, creating an obstacle to observing this process. Fortunately, Webb’s ability to peer in the infrared is an asset in navigating these murky conditions. Additionally, these NIRCam images of the very centre of the starburst were obtained using an instrument mode that prevented the very bright source from overwhelming the detector.

An edge-on spiral starburst galaxy with a bright white, glowing core set against the black background of space. A white band of the edge-on disc extends from lower left to upper right. Dark brown tendrils of dust are scattered thinly along this band. Many white points in various sizes — stars or star clusters — are scattered throughout the image, but are most heavily concentrated toward the centre. Many clumpy, red filaments extend vertically above and below the plane of the galaxy.
Astronomers used the NASA/ESA/CSA James Webb Space Telescope to look toward M82’s centre, where a galactic wind is being launched as a result of rapid star formation and subsequent supernovae. Studying the galactic wind can offer insight into how the loss of gas shapes the future growth of the galaxy.
This image from Webb’s NIRCam (Near-Infrared Camera) instrument shows M82’s galactic wind via emission from sooty chemical molecules known as polycyclic aromatic hydrocarbons (PAHs). PAHs are very small dust grains that survive in cooler temperatures but are destroyed in hot conditions. The structure of the emission resembles that of hot, ionised gas, suggesting PAHs may be replenished by continued ionisation of molecular gas.
In this image, light at 3.35 microns is coloured red, 2.50 microns is green, and 1.64 microns is blue (filters F335M, F250M, and F164N, respectively).
Credit: NASA, ESA, CSA, STScI, A. Bolatto (UMD)

While dark brown tendrils of dust are threaded throughout M82’s glowing white core even in this infrared view, Webb’s NIRCam has revealed a level of detail that has historically been obscured. Looking closer toward the centre, small specks depicted in green denote concentrated areas of iron, most of which are supernova remnants. Small patches that appear red signify regions where molecular hydrogen is being lit up by the radiation from a nearby young star.

“This image shows the power of Webb,” said Rebecca Levy, second author of the study, at the University of Arizona in Tucson. “Every single white dot in this image is either a star or a star cluster. We can start to distinguish all of these tiny point sources, which enables us to acquire an accurate count of all the star clusters in this galaxy.”

Looking at M82 in slightly longer infrared wavelengths, clumpy tendrils represented in red can be seen extending above and below the plane of the galaxy. These gaseous streamers are a galactic wind rushing out from the core of the starburst.

One area of focus for this research team was understanding how this galactic wind, which is caused by the rapid rate of star formation and subsequent supernovae, is being launched and influencing its surrounding environment. By resolving a central section of M82, scientists have been able to examine where the wind originates, and gain insight into how hot and cold components interact within the wind.

A section of M82 as imaged by Webb. An edge-on spiral starburst galaxy with a bright white, glowing core set against the black background of space. Dark brown tendrils of dust are scattered heavily toward the galaxy’s centre. Many white points in various sizes — stars or star clusters — are scattered throughout the image, but are most heavily concentrated toward the centre.
A team of astronomers used the NASA/ESA/CSA James Webb Space Telescope to survey the starburst galaxy Messier 82 (M82), which is located 12 million light-years away in the constellation Ursa Major. M82 hosts a frenzy of star formation, sprouting new stars 10 times faster than the Milky Way galaxy. Webb’s infrared capabilities enabled scientists to peer through curtains of dust and gas that have historically obscured the star formation process.
This image from Webb’s NIRCam (Near-Infrared Camera) instrument shows the centre of M82 with an unprecedented level of detail. With Webb’s resolution, astronomers can distinguish small, bright compact sources that are either individual stars or star clusters. Obtaining an accurate count of the stars and clusters that compose M82’s centre can help astronomers understand the different phases of star formation and the timelines for each stage.
In this image, light at 2.12 microns is coloured red, 1.64 microns is green, and 1.40 microns is blue (filters F212N, 164N, and F140M, respectively).
Credit: NASA, ESA, CSA, STScI, A. Bolatto (UMD)

Webb’s NIRCam instrument was well suited to tracing the structure of the galactic wind via emission from sooty chemical molecules known as polycyclic aromatic hydrocarbons (PAHs). PAHs can be considered as very small dust grains that survive in cooler temperatures but are destroyed in hot conditions.

Much to the team’s surprise, Webb’s view of the PAH emission highlights the galactic wind’s fine structure — an aspect previously unknown. Depicted as red filaments, the emission extends away from the central region where the heart of star formation is located. Another unanticipated find was the similarity between the structure of the PAH emission and that of the hot, ionised gas.

“It was unexpected to see the PAH emission resemble ionised gas,” said Bolatto. “PAHs are not supposed to live very long when exposed to such a strong radiation field, so perhaps they are being replenished all the time. It challenges our theories and shows us that further investigation is required.”

Webb’s observations of M82 in near-infrared light also spur further questions about star formation, some of which the team hopes to answer with additional data gathered with Webb, including that of another starburst galaxy. Two other papers from this team characterising the stellar clusters and correlations among wind components of M82 are almost finalised.

Left: Messier 82 as imaged by Hubble. Hour-glass-shaped red plumes of gas are shooting outward from above and below a bright blue, disc-shaped centre of a galaxy. This galaxy is surrounded by many white stars and set against the black background of space. Right: A section of Messier 82 as imaged by Webb. An edge-on spiral starburst galaxy with a bright white, glowing core set against the black background of space. A white band of the edge-on disc extends from lower left to upper right. Dark brown tendrils of dust are scattered thinly along this band. Many clumpy, red filaments extend vertically above and below the plane of the galaxy.
The starburst galaxy M82 was observed by the NASA/ESA Hubble Space Telescope in 2006, which showed the galaxy’s edge-on spiral disc, shredded clouds, and hot hydrogen gas. The NASA/ESA/CSA James Webb Space Telescope has observed M82’s core, capturing in unprecedented detail the structure of the galactic wind and characterising individual stars and star clusters.
The Webb image is from the telescope’s NIRCam (Near-Infrared Camera) instrument. The red filaments trace the shape of the cool component of the galactic wind via polycyclic aromatic hydrocarbons (PAHs). PAHs are very small dust grains that survive in cooler temperatures but are destroyed in hot conditions. The structure of the emission is similar to that of the ionised gas, suggesting PAHs may be replenished from cooler molecular material as it is ionised.
Credit: NASA, ESA, CSA, STScI, A. Bolatto (UMD)

In the near future, the team will have spectroscopic observations of M82 from Webb ready for their analysis, as well as complementary large-scale images of the galaxy and its wind. Spectral data will help astronomers determine accurate ages for the star clusters and provide a sense of how long each phase of star formation lasts in a starburst galaxy environment. On a broader scale, inspecting the activity in galaxies like M82 can deepen astronomers’ understanding of the early Universe.

“With these amazing Webb images, and our upcoming spectra, we can study how exactly the strong winds and shock fronts from young stars and supernovae can remove the very gas and dust from which new stars are forming,” said Torsten Böker of the European Space Agency, a co-author of the study. “A detailed understanding of this ‘feedback’ cycle is important for theories of how the early Universe evolved, because compact starbursts such as the one in M82 were very common at high redshift.”

These findings have been accepted for publication in The Astrophysical Journal.

 

Press release from ESA Webb.

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Webb looks for Fomalhaut’s asteroid belt and finds much more

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Webb asteroid belt Fomalhaut’s The NASA/ESA Hubble Space Telescope and ESA's Herschel Space Observatory, as well as the Atacama Large Millimeter/submillimeter Array (ALMA), have previously taken sharp images of the outermost belt. However, none of them found any structure interior to it. [Image description: An orange oval extends from the 1 o’clock to 7 o’clock positions. It features a prominent outer ring, a darker gap, an intermediate ring, a narrower dark gap, and a bright inner disc. At the centre is a ragged black spot indicating a lack of data.] Credit: NASA, ESA, CSA, A. Pagan (STScI), A. Gáspár (University of Arizona)

Webb looks for Fomalhaut’s asteroid belt and finds much more

Astronomers used the NASA/ESA/CSA James Webb Space Telescope to image the warm dust around a nearby young star, Fomalhaut, in order to study the first asteroid belt ever seen outside of our Solar System in infrared light. But to their surprise, they found that the dusty structures are much more complex than the asteroid and Kuiper dust belts of our Solar System. Overall, there are three nested belts extending out to 23 billion kilometres from the star — that’s 150 times the distance of Earth from the Sun. The scale of the outermost belt is roughly twice the scale of our Solar System’s Kuiper Belt of small bodies and cold dust beyond Neptune. The inner belts — which had never been seen before — were revealed by Webb for the first time.

Webb Fomalhaut’s asteroid beltThe NASA/ESA Hubble Space Telescope and ESA's Herschel Space Observatory, as well as the Atacama Large Millimeter/submillimeter Array (ALMA), have previously taken sharp images of the outermost belt. However, none of them found any structure interior to it. [Image description: An orange oval extends from the 1 o’clock to 7 o’clock positions. It features a prominent outer ring, a darker gap, an intermediate ring, a narrower dark gap, and a bright inner disc. At the centre is a ragged black spot indicating a lack of data.] Credit: NASA, ESA, CSA, A. Pagan (STScI), A. Gáspár (University of Arizona)
Webb looks for Fomalhaut’s asteroid belt and finds much more. This image of the dusty debris disc surrounding the young star Fomalhaut is from Webb’s Mid-Infrared Instrument (MIRI). It reveals three nested belts extending out to 23 billion kilometres from the star. The inner belts — which had never been seen before — were revealed by Webb for the first time.
The NASA/ESA Hubble Space Telescope and ESA’s Herschel Space Observatory, as well as the Atacama Large Millimeter/submillimeter Array (ALMA), have previously taken sharp images of the outermost belt. However, none of them found any structure interior to it.
These belts are most likely shaped by the gravitational forces produced by unseen planets. Credit: NASA, ESA, CSA, A. Pagan (STScI), A. Gáspár (University of Arizona)
The belts encircle the young hot star, which can be seen with the naked eye as the brightest star in the southern constellation Piscis Austrinus. The dusty belts are the debris from collisions of larger bodies, analogous to asteroids and comets, and are frequently described as ‘debris discs’. 

“I would describe Fomalhaut as the archetype of debris discs found elsewhere in our galaxy, because it has components similar to those we have in our own planetary system,” said András Gáspár of the University of Arizona in Tucson and lead author of a new paper describing these results. “By looking at the patterns in these rings, we can actually start to make a little sketch of what a planetary system ought to look like — if we could actually take a deep enough picture to see the suspected planets.”

The NASA/ESA Hubble Space Telescope and ESA’s Herschel Space Observatory, as well as the Atacama Large Millimeter/submillimeter Array (ALMA), have previously taken sharp images of the outermost belt. However, none of them found any structure interior to it. The inner belts have been resolved for the first time by Webb in infrared light.

“Where Webb really excels is that we’re able to physically resolve the thermal glow from dust in those inner regions. So you can see inner belts that we could never see before,” said Schuyler Wolff, another member of the team at the University of Arizona.

Hubble, ALMA, and Webb are tag-teaming to assemble a holistic view of the debris discs around a number of stars. “With Hubble and ALMA, we were able to image a bunch of Kuiper Belt analogues, and we’ve learned loads about how outer discs form and evolve,” said Wolff. “But we need Webb to allow us to image a dozen or so asteroid belts elsewhere. We can learn just as much about the inner warm regions of these discs as Hubble and ALMA taught us about the colder outer regions.”

These belts are most likely shaped by the gravitational forces produced by unseen planets. Similarly, inside our Solar System Jupiter corrals the asteroid belt, the inner edge of the Kuiper Belt is sculpted by Neptune, and the outer edge could be shepherded by as-yet-unseen bodies beyond it. As Webb images more systems, we will learn about the configurations of their planets.

Webb looks for Fomalhaut’s asteroid belt and finds much more. This image of the Fomalhaut system, captured by Webb’s Mid-Infrared Instrument (MIRI), shows compass arrows, scale bar, and colour key for reference. Labels indicate the various structures. At right, a great dust cloud is highlighted and pullouts show it in two infrared wavelengths: 23 and 25.5 microns.
The north and east compass arrows show the orientation of the image on the sky. Note that the relationship between north and east on the sky (as seen from below) is flipped relative to direction arrows on a map of the ground (as seen from above).
The scale bar is labelled in astronomical units, which is the average distance between Earth and the Sun: 150 million kilometres. The outer ring is about 240 astronomical units in diameter.
This image shows invisible mid-infrared wavelengths of light that have been translated into visible-light colours. The colour key and labels show which MIRI filters were used when collecting the light.
Credit: NASA, ESA, CSA, A. Pagan (STScI), A. Gáspár (University of Arizona)

Fomalhaut’s dust ring was discovered in 1983 in observations made by NASA’s Infrared Astronomical Satellite (IRAS). The existence of the ring has also been inferred from previous and longer-wavelength observations using submillimetre telescopes on Maunakea, Hawai‘i, NASA’s Spitzer Space Telescope, and Caltech’s Submillimeter Observatory.

“The belts around Fomalhaut are kind of a mystery novel: Where are the planets?” said George Rieke, another team member and US science lead for Webb’s Mid-Infrared Instrument (MIRI), which made these observations. “I think it’s not a very big leap to say there’s probably a really interesting planetary system around the star.”

“We definitely didn’t expect the more complex structure with the second intermediate belt and then the broader asteroid belt,” added Wolff. “That structure is very exciting because any time an astronomer sees a gap and rings in a disc, they say, ‘There could be an embedded planet shaping the rings!’”

Webb also imaged what Gáspár dubs ‘the great dust cloud’, which may be evidence for a collision occurring in the outer ring between two protoplanetary bodies. This is a different feature from the suspected planet first seen inside the outer ring by Hubble in 2008. Subsequent Hubble observations showed that by 2014 the object had vanished. A plausible interpretation is that this newly discovered feature, like the earlier one, is an expanding cloud of very fine dust particles from two icy bodies that smashed into each other.

The idea of a protoplanetary disc around a star goes back to the late 1700s when astronomers Immanuel Kant and Pierre-Simon Laplace independently developed the theory that the Sun and planets formed from a rotating gas cloud that collapsed and flattened under gravity. Debris discs develop later, following the formation of planets and dispersal of the primordial gas in the systems. They show that small bodies like asteroids are colliding catastrophically and pulverising their surfaces into huge clouds of dust and other debris. Observations of dust provide unique clues to the structure of an exoplanetary system, reaching down to Earth-sized planets and even asteroids, which are much too small to see individually.

“This very exciting result highlights the unique power of MIRI to study the structures carved by planets in the innermost regions of circumstellar discs,“ adds Gillian Wright, European principal investigator for MIRI and Director of the UK Astronomy Technology Centre (UKATC).

The team’s results are being published in the journal Nature Astronomy.

 

Press release from ESA Webb.

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Webb Reveals Intricate Networks of Gas and Dust in Nearby Galaxies

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Webb Reveals Intricate Networks of Gas and Dust in Nearby Galaxies

Researchers using the NASA/ESA/CSA James Webb Space Telescope are getting their first look at star formation, gas, and dust in nearby galaxies with unprecedented resolution at infrared wavelengths. The data have enabled an initial collection of 21 research papers which provide new insight into how some of the smallest-scale processes in the Universe — the beginnings of star formation — impact the evolution of the largest objects in our cosmos: galaxies.

The largest survey of nearby galaxies in Webb’s first year of science operations is being carried out by the Physics at High Angular resolution in Nearby Galaxies (PHANGS) collaboration, involving more than 100 researchers from around the globe. The Webb observations are led by Janice Lee, Gemini Observatory chief scientist at the US National Science Foundation’s NOIRLab and an affiliate astronomer at the University of Arizona in Tucson.

The team is studying a diverse sample of 19 spiral galaxies, and in Webb’s first few months of science operations, observations have been made of five of those targets — M74, NGC 7496, IC 5332, NGC 1365, and NGC 1433. The results are already astounding astronomers.

The images from Webb’s Mid-Infrared Instrument (MIRI) reveal the presence of a network of highly structured features within these galaxies — glowing cavities of dust and huge cavernous bubbles of gas that line the spiral arms. In some regions of the nearby galaxies observed, this web of features appears built from both individual and overlapping shells and bubbles where young stars are releasing energy.

The high-resolution imaging needed to study these structures has long evaded astronomers — that is, until Webb came into the picture. Webb’s powerful infrared capabilities can pierce through the dust to connect the missing pieces of the puzzle. For example, specific wavelengths observable by MIRI (7.7 and 11.3 microns) are sensitive to emission from polycyclic aromatic hydrocarbons, which play a crucial role in the formation of stars and planets. These molecules were detected by Webb in the first observations by the PHANGS programme.

Studying these interactions at the finest scales can help provide insights into the larger picture of how galaxies have evolved over time.

The PHANGS team will work to create and release datasets that align Webb’s data to each of the complementary datasets obtained previously from the other observatories, to help accelerate discoveries by the broader astronomical community.

The research by the PHANGS team is being conducted as part of the General Observer program 2107. The team’s initial findings, comprising 21 individual studies, were recently published in a special focus issue of The Astrophysical Journal Letters.

Press release from ESA Webb

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