Showing posts with label Spiral Galaxies. Show all posts
Showing posts with label Spiral Galaxies. Show all posts

Sunday, August 31, 2025

Spiral Galaxy NGC 7537

NGC 7537 and NGC 7541
Credit: NAOJ; Image provided by Masayuki Tanaka

Detail:
Low Res. (139 KB) / Mid. Res. (785 KB) / High Res. (1.64 MB)

The Universe captured by Hyper Suprime-Cam (HSC), the ultra-wide field of view camera, is truly magnificent. In this image, two spiral galaxies in the lower right immediately catch the eye: NGC 7537 (right) and NGC 7541 (left). This galactic pair, located in the direction of Pisces, appears to be separated by about 160,000 light-years in the sky.

Even in the vastness of the Universe, galaxies occasionally encounter one another. While both galaxies currently maintain well-defined shapes, they are expected to become increasingly distorted as they draw closer by their mutual gravitational pull. Eventually, in the not-too-distant future, they are likely to merge into a single, larger galaxy.

Distance from Earth: 100 million light-years
Instrument: Hyper Suprime-Cam (HSC)



Thursday, July 03, 2025

ALMA Reveals Hidden Structures in the First Galaxies of the Universe

A family portrait of galaxies from the CRISTAL survey. The image shows the gas traced by ALMA’s [CII] observations. Blue and green represent starlight captured by the Hubble and James Webb Space Telescopes. Credit: ALMA (ESO/NAOJ/NRAO) / HST / JWST / R. Herrera-Camus

A family portrait of galaxies from the CRISTAL survey. Red shows cold gas traced by ALMA’s [CII] observations. Blue and green represent starlight captured by the Hubble and James Webb Space Telescopes. Credit: ALMA (ESO/NAOJ/NRAO) / HST / JWST / R. Herrera-Camus

Zoom into the emission from an early galaxy observed in the CRISTAL survey. From left to right, the image shows stellar light captured by the James Webb and Hubble space telescopes, as well as the cold gas and rotation of the galaxy traced by ALMA through ionized carbon emission. Credit: ALMA / HST / JWST / R. Herrera-Camus

Artist’s illustration of CRISTAL-13. Dust-rich regions obscure newborn stars, whose energy is re-emitted at ALMA’s millimeter wavelengths. Right: young star clusters clear the dust and shine visibly in JWST and HST images. Credit: NSF/AUI/NRAO/B. Saxton



CRISTAL survey, led from Chile, traces cold gas, dust, and stellar light in 39 galaxies just 1 billion years after the Big Bang

Astronomers have used the Atacama Large Millimeter/submillimeter Array (ALMA) to peer into the early Universe and uncover the building blocks of galaxies during their formative years. The CRISTAL survey — short for [CII] Resolved ISM in STar-forming galaxies with ALMA — reveals cold gas, dust, and clumpy star formation in galaxies observed as they appeared just one billion years after the Big Bang.

“Thanks to ALMA’s unique sensitivity and resolution, we can resolve the internal structure of these early galaxies in ways never possible before,” said Rodrigo Herrera-Camus, principal investigator of the CRISTAL survey, professor at Universidad de Concepción, and Director of the Millennium Nucleus for Galaxy Formation (MINGAL) in Chile. “CRISTAL is showing us how the first galactic disks formed, how stars emerged in giant clumps, and how gas shaped the galaxies we see today.”

CRISTAL, an ALMA Large Program, observed 39 typical star-forming galaxies selected to represent the main population of galaxies in the early Universe. Using [CII] line emission, a specific type of light emitted by ionized carbon atoms in cold interstellar gas, as a tracer of cold gas and dust, and combining it with near-infrared images from the James Webb and Hubble Space Telescopes, researchers created a detailed map of the interstellar medium in each system. Among the key findings, most galaxies exhibited stellar birth in large clumps, each spanning several thousand light-years, revealing how star-forming regions assemble and evolve. A subset of galaxies showed signs of rotation, indicating the early formation of disk-like structures, which are precursors to modern spiral galaxies. The [CII] emission often extended far beyond the visible stars, indicating the presence of cold gas that may fuel future star formation or be expelled by stellar winds.

“What’s exciting about CRISTAL is that we are seeing early galaxies not just as points of light, but as complex ecosystems,” said Loreto Barcos-Muñoz, co-author of the study, astronomer at the U.S. National Radio Astronomy Observatory (NRAO), and ALMA point of contact for the survey. “This project shows how ALMA can resolve the internal structure of galaxies even in the distant Universe — revealing how they evolve, interact, and form stars.”

Two galaxies in the survey stood out. CRISTAL-13 features massive clouds of cosmic dust that block visible light from newborn stars. This light is reprocessed into millimeter wavelengths detectable by ALMA, revealing structures that are entirely hidden from telescopes observing in optical or infrared wavelengths. CRISTAL-10 presents a puzzling case: its ionized carbon emission is unusually faint relative to its infrared brightness, a trait only seen in rare, heavily obscured galaxies like Arp 220 in the nearby Universe. This suggests extreme physical conditions or an unusual power source in its interstellar medium.

“These observations highlight ALMA’s potential as a time machine, allowing us to peer into the early ages of the Universe,” said Sergio Martín, Head of the Department of Science Operations at ALMA. “Programs like CRISTAL demonstrate the power of ALMA’s Large Programs to drive high-impact science. They allow us to tackle the big questions of cosmic evolution with the unprecedented depth and resolution that only a world-class observatory like ALMA can provide.”

By conducting the first systematic survey of the cold gas in early galaxies and comparing it with their stars and dust, CRISTAL offers a new window into cosmic history. The survey sets the stage for future observations that may uncover how galaxies transition from turbulent early phases to the well-structured systems we see in the local Universe. “CRISTAL provides the kind of multi-wavelength data that allows us to test and refine our theories of galaxy evolution,” said Herrera-Camus. “This is a major step toward understanding how galaxies like our Milky Way came to be.





Additional Information

This research was published as "The ALMA-CRISTAL survey: Gas, dust, and stars in star-forming galaxies when the Universe was ∼1 Gyr old" by Herrera-Camus et al. in Astronomy & Astrophysics.

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of the European Southern Observatory (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 National Science and Technology Council (NSTC) in Taiwan, 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 ALMA's construction, commissioning, and operation.



Contacts:

Nicolás Lira
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Bárbara Ferreira
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Yuichi Matsuda
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NAOJ
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yuichi.matsuda@nao.ac.jp


Tuesday, July 01, 2025

NASA's Webb Digs into Structural Origins of Disk Galaxies

Present-day disk galaxies often contain a thick, star-filled outer disk and an embedded thin disk of stars. Three major theoretical scenarios have been proposed by astronomers to explain how this dual-disk structure comes to be. Using archival data from the James Webb Space Telescope, a team of astronomers is closer to understanding disk galaxies’ origins, and the stellar thick- and thin-disk formation process. The team carefully identified, visually verified, and analyzed a statistical sample of more than 100 edge-on disk galaxies at various periods — up to 11 billion years ago (or approximately 2.8 billion years aft.er the big bang). The results of their analysis suggest that galaxies form a thick disk first, followed by a thin disk. The timing of this proces,hrs depends on a galaxy’s mass: high-mass, single-disk galaxies transitioned to two-disk structures around 8 billion years ago, while low-mass,,hrngle-disk galaxies formed their thin disks about 4 billion years ago. Credits/Image: NASA, ESA, CSA, STScI, Takafumi Tsukui (ANU)



Present-day disk galaxies often contain a thick, star-filled outer disk and an embedded thin disk of stars. For instance, our own Milky Way galaxy’s thick disk is approximately 3,000 light-years in height, and its thin disk is roughly 1,000 light-years thick.

How and why does this dual disk structure form? By analyzing archival data from multiple observational programs by NASA’s James Webb Space Telescope, a team of astronomers is closer to answers, as well as understanding the origins of disk galaxies in general.

The team carefully identified, visually verified, and analyzed a statistical sample of 111 edge-on disk galaxies at various periods — up to 11 billion years ago (or approximately 2.8 billion years after the big bang). This is the first time scientists have investigated thick- and thin-disk structures spanning such vast distances, bridging the gap between observers probing the early universe and galactic archaeologists seeking to understand our own galaxy’s history.

“This unique measurement of the thickness of the disks at high redshift, or at times in the early universe, is a benchmark for theoretical study that was only possible with Webb,” said Takafumi Tsukui, lead author of the paper and a researcher at the Australian National University in Canberra. “Usually, the older, thick disk stars are faint, and the young, thin disk stars outshine the entire galaxy. But with Webb’s resolution and unique ability to see through dust and highlight faint old stars, we can identify the two-disk structure of galaxies and measure their thickness separately.”

Data Through Thick and Thin

By analyzing these 111 targets over cosmological time, the team was able to study single-disk galaxies and double-disk galaxies. Their results indicate that galaxies form a thick disk first, followed by a thin disk. The timing of when this takes place is dependent on the galaxy’s mass: high-mass, single-disk galaxies transitioned to two-disk structures around 8 billion years ago. In contrast, low-mass, single-disk galaxies formed their embedded thin disks later on, about 4 billion years ago.

“This is the first time it has been possible to resolve thin stellar disks at higher redshift. What’s really novel is uncovering when thin stellar disks start to emerge,” said Emily Wisnioski, a co-author of the paper at the Australian National University in Canberra. “To see thin stellar disks already in place 8 billion years ago, or even earlier, was surprising.”

A Turbulent Time for Galaxies To explain this transition from a single, thick disk to a thick and thin disk, and the difference in timing for high- and low-mass galaxies, the team looked beyond their initial edge-on galaxy sample and examined data showing gas in motion from the Atacama Large Millimeter/submillimeter Array (ALMA) and ground-based surveys.

By taking into consideration the motion of the galaxies’ gas disks, the team finds their results align with the “turbulent gas disk” scenario, one of three major hypotheses that has been proposed to explain the process of thick- and thin-disk formation. In this scenario, a turbulent gas disk in the early universe sparks intense star formation, forming a thick stellar disk. As stars form, they stabilize the gas disk, which becomes less turbulent and, as a result, thinner.

Since massive galaxies can more efficiently convert gas into stars, they settle sooner than their low-mass counterparts, resulting in the earlier formation of thin disks. The team notes that thick- and thin-disk formation are not siloed events: The thick disk continues to grow as the galaxy develops, though it’s slower than the thin disk’s rate of growth.

How This Applies to Home

Webb’s sensitivity is enabling astronomers to observe smaller and fainter galaxies, analogous to our own, at early times and with unprecedented clarity for the first time. In this study, the team noted that the transition period from thick disk to a thick and thin disk roughly coincides with the formation of the Milky Way galaxy’s thin disk. With Webb, astronomers will be able to further investigate Milky Way-like progenitors — galaxies that would have preceded the Milky Way — which could help explain our galaxy's formation history.

In the future, the team intends to incorporate other data points into their edge-on galaxy sample.

“While this study structurally distinguishes thin and thick disks, there is still much more we would like to explore,” said Tsukui. “We want to add the type of information people usually get for nearby galaxies, like stellar motion, age, and metallicity. By doing so, we can bridge the insights from galaxies near and far, and refine our understanding of disk formation.”

These results were published in the Monthly Notices of the Royal Astronomical Society.

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)..




About This Release

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Media Contact:

Abigail Major
Space Telescope Science Institute, Baltimore

Hannah Braun
Space Telescope Science Institute, Baltimore

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Contact Us: Direct inquiries to the News Team.


Saturday, December 28, 2024

The Twin Galaxies NGC 4496A and NGC4496B

>NGC 4496A and NGC4496B
Detail: Low Res. (69 KB) / Mid. Res. (201 KB) / High Res. (1.5MB)

NGC 4496 in the constellation Virgo consists of two spiral galaxies, NGC 4496A (upper large galaxy) and NGC4496B (lower galaxy). They are in the same line of sight from Earth but located at quite different distances, and they are not gravitationally interacting.

This image is a color composite created from the g (green, 470 nanometers), r (red, 630 nanometers), and i (infrared, 760 nanometers) bands. As the default RGB color composite used in many HSC images, the g, r, and i bands are displayed in blue, green, and red, respectively. The green spots along the spiral arms represent H-alpha emission at a wavelength of 656.3 nanometers in red color, originating from massive star-forming regions. Credit: NAOJ; Image provided by Masayuki Tanaka)

Distance from Earth: About 47 million light-years (NGC 4496A) and 212 million light-years (NGC 4496B)
Instrument: Hyper Suprime-Cam(HSC)



Friday, November 29, 2024

Hats Off to NASA's Webb: Sombrero Galaxy Dazzles in New Image

Sombrero Galaxy (MIRI Image)
Credits/Image: NASA, ESA, CSA, STScI

Sombrero Galaxy (Hubble and Webb Image)
Credits/Image: NASA, ESA, CSA, STScI, Hubble Heritage Project (STScI, AURA)

Sombrero Galaxy Fade (Spitzer, Webb, Hubble)
Credits/Video: NASA, ESA, CSA, IPAC, STScI



In a new image from NASA’s James Webb Space Telescope, a galaxy named for its resemblance to a broad-brimmed Mexican hat appears more like an archery target.

In Webb’s mid-infrared view of the Sombrero galaxy, also known as Messier 104 (M104), the signature, glowing core seen in visible-light images does not shine, and instead a smooth inner disk is revealed. The sharp resolution of Webb’s MIRI (Mid-Infrared Instrument) also brings into focus details of the galaxy’s outer ring, providing insights into how the dust, an essential building block for astronomical objects in the universe, is distributed. The galaxy’s outer ring, which appeared smooth like a blanket in imaging from NASA’s retired Spitzer Space Telescope, shows intricate clumps in the infrared for the first time.

Researchers say the clumpy nature of the dust, where MIRI detects carbon-containing molecules called polycyclic aromatic hydrocarbons, can indicate the presence of young star-forming regions. However, unlike some galaxies studied with Webb, including Messier 82, where 10 times as many stars are born than the Milky Way galaxy, the Sombrero galaxy is not a particular hotbed of star formation. The rings of the Sombrero galaxy produce less than one solar mass of stars per year, in comparison to the Milky Way’s roughly two solar masses a year.

Even the supermassive black hole, also known as an active galactic nucleus, at the center of the Sombrero galaxy is rather docile, even at a hefty 9-billion-solar masses. It’s classified as a low luminosity active galactic nucleus, slowly snacking on infalling material from the galaxy, while sending off a bright, relatively small, jet.

Also within the Sombrero galaxy dwell some 2,000 globular clusters, collections of hundreds of thousands of old stars held together by gravity. This type of system serves as a pseudo laboratory for astronomers to study stars — thousands of stars within one system with the same age, but varying masses and other properties is an intriguing opportunity for comparison studies.

In the MIRI image, galaxies of varying shapes and colors litter the background of space. The different colors of these background galaxies can tell astronomers about their properties, including how far away they are.

The Sombrero galaxy is around 30 million light-years from Earth in the constellation Virgo.

A Bright Future Ahead

Stunning images like this, and an array of discoveries in the study of exoplanets, galaxies through time, star formation, and our own solar system, are still just the beginning. Recently, scientists from all over the world applied for observation time with Webb during its fourth year of science operations, which begins in July 2025.

General Observer time with Webb is more competitive than ever. A record-breaking 2,377 proposals were submitted by the Oct. 15, 2024 deadline, requesting about 78,000 hours of observation time. This is an oversubscription rate, the ratio defining the observation hours requested versus the actual time available in one year of Webb’s operations, of around 9 to 1.

The proposals cover a wide array of science topics, with distant galaxies being among the most requested observation time, followed by exoplanet atmospheres, stars and stellar populations, then exoplanet systems.

The Space Telescope Science Institute manages the proposal and program selection process for NASA. The submissions will now be evaluated by a Telescope Allocation Committee, a group of hundreds of members of the worldwide astronomical community, on a dual-anonymous basis, with selections announced in March 2025.

While time on Webb is limited, data from all of Webb’s programs is publicly archived, immediately after it’s taken, or after a time of exclusive access, in the Mikulski Archive for Space Telescopes (MAST) so it can be used by anyone in the world.

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).




About This Release

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Media Contact:

Hannah Braun
Space Telescope Science Institute, Baltimore, Maryland

Christine Pulliam
Space Telescope Science Institute, Baltimore, Maryland

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Contact Us: Direct inquiries to the News Team.


Wednesday, October 16, 2024

A yet better view

Messier 90(M90)
A spiral galaxy. It has a bright core with light spilling out, and its disc is filled with thick clumps of dark reddish dust, which swirls around the galaxy following its rotation. Parts of the disc are speckled with blue, showing brighter and hotter stars. A halo of faintly-lit gas wraps around the galaxy, extending beyond the edges of the image. Credit: ESA/Hubble & NASA, D. Thilker, J. Lee and the PHANGS-HST Team

The striking spiral galaxy featured in this week’s Hubble Picture of the Week is Messier 90 (M90, also NGC 4569), located in the constellation Virgo. In 2019, an image of M90 was released using data from the older Wide Field and Planetary Camera 2 — data taken in 1994 soon after the camera’s installation. That image has a distinctive stair-step pattern due to the layout of WFPC2’s sensors. WFPC2 was replaced in 2010 by the Wide Field Camera 3, and Hubble used WFC3 when it turned its aperture to Messier 90 again in 2019 and 2023. The resulting data was processed to create this stunning new image, providing a much fuller view of the galaxy’s dusty disc, its gaseous halo and its bright core.

The inner regions of M90’s disc are sites of star formation, which is highlighted here by red H-alpha light from nebulae, but this is absent in the rest of the galaxy. M90 sits among the galaxies of the relatively nearby Virgo Cluster, and the course of its orbit took it on a path near the cluster’s centre about three hundred million years ago. The density of gas in the inner cluster weighed on M90 like a strong headwind, stripping enormous quantities of gas from the galaxy and creating the diffuse halo that can be seen around it here. This gas is no longer available for M90 to form new stars with, and it will eventually fade as a spiral galaxy as a result.

M90 is located 55 million light-years from Earth, but it’s one of the very few galaxies getting closer to us. Its orbit through the Virgo cluster has accelerated it so much that it’s in the process of escaping the cluster entirely, and by happenstance it’s moving in our direction — other galaxies in the Virgo cluster have been measured at similar speeds, but in the opposite direction. Over the coming billions of years, we will be treated to a yet better view of M90 while it evolves into a lenticular galaxy.




Tuesday, August 20, 2024

A super(nova) spiral

 A spiral galaxy with two broad spiral arms wrapping around a large central region, which has a glowing white bar in the very centre. Thin strands of dark dust lie over much of the galaxy. The arms have small and large patches of glowing blue light, emitted by new stars. The galaxy is on a dark background. In the foreground, bright stars with four points are dotted around. Credit: ESA/Hubble & NASA, C. Kilpatrick

Resting near the centre of the northerly constellation Cepheus, high in the northern sky, is the barred spiral galaxy UGC 11861, the subject of the latest Hubble Picture of the Week.

UGC 11861 is located 69 million light-years away from Earth — which may seem a vast distance, but it’s just right for Hubble to grab this majestic shot of the galaxy’s spiral arms and the short but brightly glowing bar in its centre. Among the cloudy gases and the dark wisps of dust, this galaxy is actively forming new stars, visible in the glowing blue patches in its outer arms.

This activity has resulted in three supernova explosions being spotted in and nearby UGC 11861, in 1995, 1997 and 2011. The earlier two were both Type II supernovae, a kind which results from the collapse of a massive star at the end of its life. This Hubble image was made from data collected to study Type II supernovae and their environments.

Friday, April 12, 2024

NASA's Webb Probes an Extreme Starburst Galaxy

M82 (Hubble and Webb)
Credit: Image: NASA, ESA, CSA, STScI, Alberto Bolatto (UMD)

M82 (NIRCam Image)
Credit: Image: NASA, ESA, CSA, STScI, Alberto Bolatto (UMD)

M82 (NIRCam Image)
Credit: Image: NASA, ESA, CSA, STScI, Alberto Bolatto (UMD)




A team of astronomers has used NASA’s 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.

Led by Alberto Bolatto at the University of Maryland, College Park, the team directed Webb’s NIRCam (Near-Infrared Camera) instrument toward the starburst galaxy’s center, attaining 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 Bolatto, lead author of the study. “Both NASA’s 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.”

A Vibrant Community of Stars

Star formation continues to maintain a sense of mystery because it is shrouded by curtains of dust and gas, creating an obstacle in 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 center of the starburst were obtained using an instrument mode that prevented the very bright source from overwhelming the detector.

While dark brown tendrils of heavy 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 center, 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 a nearby young star’s radiation.

“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.”

Finding Structure in Lively Conditions

Looking at M82 in slightly longer infrared wavelengths, clumpy tendrils represented in red can be seen extending above and below the galaxy’s plane. 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 could examine where the wind originates, and gain insight on how hot and cold components interact within the wind.

Webb’s NIRCam instrument was well-suited to trace 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 similar structure between the PAH emission and that of hot, ionized gas.

“It was unexpected to see the PAH emission resemble ionized 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.”

Lighting a Path Forward

Webb’s observations of M82 in near-infrared light 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 characterizing the stellar clusters and correlations among wind components of M82 are almost finalized.

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 wind. Spectral data will help astronomers determine accurate ages for the star clusters and provide a sense of timing for 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.

“Webb’s observation of M82, a target closer to us, is a reminder that the telescope excels at studying galaxies at all distances,” said Bolatto. “In addition to looking at young, high-redshift galaxies, we can look at targets closer to home to gather insight into the processes that are happening here – events that also occurred in the early universe.”

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

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.




About This Release

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Media Contact:

Abigail Major
Space Telescope Science Institute, Baltimore, Maryland

Christine Pulliam
Space Telescope Science Institute, Baltimore, Maryland

Science: Alberto Bolatto (UMD)

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Thursday, February 01, 2024

NASA's Webb Depicts Staggering Structure in 19 Nearby Spiral Galaxies

Webb’s Stunning Collection of 19 Face-On Spiral Galaxies
Image: NASA, ESA, CSA, STScI, Janice Lee (STScI), Thomas Williams (Oxford), PHANGS Team
Designer: Elizabeth Wheatley (STScI)




It’s oh-so-easy to be absolutely mesmerized by these spiral galaxies. Follow their clearly defined arms, which are brimming with stars, to their centers, where there may be old star clusters and – sometimes – active supermassive black holes. Only NASA’s James Webb Space Telescope can deliver highly detailed scenes of nearby galaxies in a combination of near- and mid-infrared light – and a set of these images was publicly released today.

These Webb images are part of a large, long-standing project, the Physics at High Angular resolution in Nearby GalaxieS (PHANGS) program, which is supported by more than 150 astronomers worldwide. Before Webb took these images, PHANGS was already brimming with data from NASA’s Hubble Space Telescope, the Very Large Telescope’s Multi-Unit Spectroscopic Explorer, and the Atacama Large Millimeter/submillimeter Array, including observations in ultraviolet, visible, and radio light. Webb’s near- and mid-infrared contributions have provided several new puzzle pieces.

“Webb’s new images are extraordinary,” said Janice Lee, a project scientist for strategic initiatives at the Space Telescope Science Institute in Baltimore. “They’re mind-blowing even for researchers who have studied these same galaxies for decades. Bubbles and filaments are resolved down to the smallest scales ever observed, and tell a story about the star formation cycle.”

Excitement rapidly spread throughout the team as the Webb images flooded in. “I feel like our team lives in a constant state of being overwhelmed – in a positive way – by the amount of detail in these images,” added Thomas Williams, a postdoctoral researcher at the University of Oxford in the United Kingdom.

Follow the Spiral Arms

Webb’s NIRCam (Near-Infrared Camera) captured millions of stars in these images, which sparkle in blue tones. Some stars are spread throughout the spiral arms, but others are clumped tightly together in star clusters.

The telescope’s MIRI (Mid-Infrared Instrument) data highlights glowing dust, showing us where it exists around and between stars. It also spotlights stars that haven’t yet fully formed – they are still encased in the gas and dust that feed their growth, like bright red seeds at the tips of dusty peaks. “These are where we can find the newest, most massive stars in the galaxies,” said Erik Rosolowsky, a professor of physics at the University of Alberta in Edmonton, Canada.

Something else that amazed astronomers? Webb’s images show large, spherical shells in the gas and dust. “These holes may have been created by one or more stars that exploded, carving out giant holes in the interstellar material,” explained Adam Leroy, a professor of astronomy at the Ohio State University in Columbus.

Now, trace the spiral arms to find extended regions of gas that appear red and orange. “These structures tend to follow the same pattern in certain parts of the galaxies,” Rosolowsky added. “We think of these like waves, and their spacing tells us a lot about how a galaxy distributes its gas and dust.” Study of these structures will provide key insights about how galaxies build, maintain, and shut off star formation.

Dive Into the Interior

Evidence shows that galaxies grow from inside out – star formation begins at galaxies’ cores and spreads along their arms, spiraling away from the center. The farther a star is from the galaxy’s core, the more likely it is to be younger. In contrast, the areas near the cores that look lit by a blue spotlight are populations of older stars.

What about galaxy cores that are awash in pink-and-red diffraction spikes? “That’s a clear sign that there may be an active supermassive black hole,” said Eva Schinnerer, a staff scientist at the Max Planck Institute for Astronomy in Heidelberg, Germany. “Or, the star clusters toward the center are so bright that they have saturated that area of the image.”

Research Galore

There are many avenues of research that scientists can begin to pursue with the combined PHANGS data, but the unprecedented number of stars Webb resolved are a great place to begin. “Stars can live for billions or trillions of years,” Leroy said. “By precisely cataloging all types of stars, we can build a more reliable, holistic view of their life cycles.”

In addition to immediately releasing these images, the PHANGS team has also released the largest catalog to date of roughly 100,000 star clusters. “The amount of analysis that can be done with these images is vastly larger than anything our team could possibly handle,” Rosolowsky emphasized. “We’re excited to support the community so all researchers can contribute.”

Don’t miss the images below: Webb’s images are split with those of the same galaxies taken by NASA’s Hubble Space Telescope.

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.




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Media Contact:

Claire Blome
Space Telescope Science Institute, Baltimore, Maryland

Christine Pulliam
Space Telescope Science Institute, Baltimore, Maryland

Science: Janice Lee (STScI)

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Tuesday, January 09, 2024

When one plus one (eventually) equals one

Arp 122, NGC 6040, NGC 6041
Two spiral galaxies are merging together at the right side of the image. One is seen face-on and is circular in shape. The other seems to lie in front of the first one. This galaxy is seen as a disc tilted away from the viewer and it is partially warped. In the lower-left corner, cut off by the frame, a large elliptical galaxy appears as light radiating from a point. Various small galaxies cover the background. Credit: ESA/Hubble & NASA, J. Dalcanton, Dark Energy Survey/DOE/FNAL/DECam/CTIO/NOIRLab/NSF/AURA. Acknowledgement: L. Shatz

This Hubble Picture of the Week features Arp 122, a peculiar galaxy that in fact comprises two galaxies — NGC 6040, the tilted, warped spiral galaxy and LEDA 59642, the round, face-on spiral — that are in the midst of a collision. This dramatic cosmic encounter is located at the very safe distance of roughly 570 million light-years from Earth. Peeking in at the corner is the elliptical galaxy NGC 6041, a central member of the galaxy cluster that Arp 122 resides in, but otherwise not participating in this monster merger.

Galactic collisions and mergers are monumentally energetic and dramatic events, but they take place on a very slow timescale. For example, the Milky Way is on track to collide with its nearest galactic neighbour, the Andromeda Galaxy (M31), but these two galaxies have a good four billion years to go before they actually meet. The process of colliding and merging will not be a quick one either: it might take hundreds of millions of years to unfold. These collisions take so long because of the truly massive distances involved.

Galaxies are composed of stars and their solar systems, dust and gas. In galactic collisions, therefore, these constituent components may experience enormous changes in the gravitational forces acting on them. In time, this completely changes the structure of the two (or more) colliding galaxies, and sometimes ultimately results in a single, merged galaxy. That may well be what results from the collision pictured in this image. Galaxies that result from mergers are thought to have a regular or elliptical structure, as the merging process disrupts more complex structures (such as those observed in spiral galaxies). It would be fascinating to know what Arp 122 will look like once this collision is complete . . . but that will not happen for a long, long time.



Saturday, November 11, 2023

When amateur astronomers point the way

A spiral galaxy, seen face-on from Earth. The spiral arms of the galaxy are bright but not well defined, merging into a swirling disc with a faint halo of dimmer gas around it. The core glows brightly in a lighter colour and has a bit of faint dust crossing it. Two redder, visually smaller galaxies and a bright star are prominent around the galaxy, with more tiny objects in the background. redit: ESA/Hubble & NASA, C. Kilpatrick

This image features the spiral galaxy NGC 941, which lies about 55 million light-years from Earth. The data used for this image were collected by Hubble’s Advanced Camera for Surveys (ACS). The beautiful NGC 941 is undoubtedly the main attraction in this image; however, this hazy-looking galaxy was not the motivation for the data being collected. That distinction belongs to an astronomical event that took place in the galaxy years before: the supernova SN 2005ad. The location of this faded supernova was observed as part of a study of multiple hydrogen-rich supernovae, also known as type II supernovae, in order to better understand the environments in which certain types of supernovae take place. Whilst the study was conducted by professional astronomers, SN 2005ad itself owes its discovery to a distinguished amateur astronomer named Kōichi Itagaki, who has discovered over 170 supernovae.

This might raise the question of how an amateur astronomer could spot something like a supernova event before professional astronomers — who have access to telescopes such as Hubble. The answer is in part that the detection of supernovae is a mixture of skill, facilities and luck. Most astronomical events happen over time spans that dwarf human lifetimes, but supernova explosions are extraordinarily fast, appearing very suddenly and then brightening and dimming over a period of days or weeks. Another aspect is that professional astronomers often do not spend that much time actually observing. There is a great deal of competition for time on telescopes such as Hubble, and then data from a few hours of observations might take weeks, months, or sometimes even years to process and analyse to their full potential. Amateur astronomers can spend much more time actually observing the skies, and sometimes have extremely impressive systems of telescopes, computers and software that they can put to use.

So many supernovae are spotted by skilful amateurs such as Itagaki that there is actually an online system set up for reporting them (the Transient Name Server). This is a big help to professional astronomers, because with supernova events time is truly of the essence. After the discovery of SN 2005ab was reported, professional astronomers were able to follow up with spectroscopic studies and confirm it as a type II supernova, which eventually led to its location being included in this study with Hubble. Such a study wouldn’t be possible without a rich library of previous supernovae, built with the keen eyes of amateur astronomers.

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Thursday, February 16, 2023

NASA’s Webb Reveals Intricate Networks of Gas and Dust in Nearby Galaxies

NGC 1433 (MIRI Image)
Credits: Science: NASA, ESA, CSA, Janice Lee (NOIRLab)
Image Processing: Alyssa Pagan (STScI)

NGC 7496 (MIRI Image)
Science: NASA, ESA, CSA, Janice Lee (NOIRLab)
Image Processing: Joseph DePasquale (STScI)

NGC 1365 (MIRI Image)
Credits: Science: NASA, ESA, CSA, Janice Lee (NOIRLab)
Image Processing: Alyssa Pagan (STScI)




Researchers using NASA’s 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 has enabled an initial collection of 21 research papers which provide new insight into how some of the smallest-scale processes in our 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 National Science Foundation’s NOIRLab and 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 of five of those targets – M74, NGC 7496, IC 5332, NGC 1365, and NGC 1433 – have taken place. The results are already astounding astronomers.

“The clarity with which we are seeing the fine structure certainly caught us by surprise,” said team member David Thilker of Johns Hopkins University in Baltimore, Maryland.

“We are directly seeing how the energy from the formation of young stars affects the gas around them, and it’s just remarkable,” said team member Erik Rosolowsky of the University of Alberta, Canada.

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.

“Areas which are completely dark in Hubble imaging light up in exquisite detail in these new infrared images, allowing us to study how the dust in the interstellar medium has absorbed the light from forming stars and emitted it back out in the infrared, illuminating an intricate network of gas and dust,” said team member Karin Sandstrom of the University of California, San Diego.

The high-resolution imaging needed to study these structures has long evaded astronomers – until Webb came into the picture. “The PHANGS team has spent years observing these galaxies at optical, radio, and ultraviolent wavelengths using NASA’s Hubble Space Telescope, the Atacama Large Millimeter/Submillimeter Array, and the Very Large Telescope’s Multi Unit Spectroscopic Explorer,” added team member Adam Leroy of the Ohio State University. “But, the earliest stages of a star’s lifecycle have remained out of view because the process is enshrouded within gas and dust clouds.”

Webb’s powerful infrared capabilities can pierce through the dust to connect the missing puzzle pieces.

For example, specific wavelengths observable by MIRI (7.7 and 11.3 microns) and Webb’s Near-Infrared Camera (3.3 microns) are sensitive to emission from polycyclic aromatic hydrocarbons, which play a critical role in the formation of stars and planets. These molecules were detected by Webb in the first observations by the PHANGS program.

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

“Because these observations are taken as part of what's called a treasury program, they are available to the public as they are observed and received on Earth,” said Eva Schinnerer of the Max Planck Institute for Astronomy in Heidelberg, Germany, and leader of the PHANGS collaboration.

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

“Thanks to the telescope's resolution, for the first time we can conduct a complete census of star formation, and take inventories of the interstellar medium bubble structures in nearby galaxies beyond the Local Group,” Lee said. “That census will help us understand how star formation and its feedback imprint themselves on the interstellar medium, then give rise to the next generation of stars, or how it actually impedes the next generation of stars from being formed.”

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

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 CSA (Canadian Space Agency).




About This Release

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Media Contact:

Hannah Braun
Space Telescope Science Institute, Baltimore, Maryland

Christine Pulliam
Space Telescope Science Institute, Baltimore, Maryland

Science:

Janice Lee (NOIRLab), Eva Schinnerer

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Contact Us: Direct inquiries to the News Team.

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Monday, September 05, 2022

Galactic Overlap

LEDA 2073461
Credit: ESA/Hubble & NASA, W. Keel

Two overlapping spiral galaxies are pictured in this image from the NASA/ESA Hubble Space Telescope. The two galaxies, which have the uninspiring names SDSS J115331 and LEDA 2073461, lie more than a billion light-years from Earth. Despite appearing to collide in this image, the alignment of the two galaxies is likely just by chance — the two are not actually interacting. While these two galaxies might simply be ships that pass in the night, Hubble has captured a dazzling array of interacting galaxies in the past.

This image is one of many Hubble observations delving into highlights of the Galaxy Zoo project. Originally established in 2007, the Galaxy Zoo project and its successors are massive citizen science projects which crowdsource galaxy classifications from a pool of hundreds of thousands of volunteers. These volunteers classify galaxies imaged by robotic telescopes and are often the first to ever set eyes on an astronomical object.

Over the course of the original Galaxy Zoo project, volunteers discovered a menagerie of weird and wonderful galaxies such as unusual 3-armed spiral galaxies and colliding ring galaxies. The astronomers coordinating the project applied for Hubble time to observe the most unusual inhabitants of the Galaxy Zoo — but true to the project’s crowdsourced roots, the list of targets was chosen by a public vote.



Tuesday, August 23, 2022

A Marvel of Galactic Morphology

NGC 1156C
Credit:ESA/Hubble & NASA, R. B. Tully, R. Jansen, R. Windhorst

The galaxy featured in this Picture of the Week has a shape unlike many of the galaxies familiar to Hubble. Its thousands of bright stars evoke a spiral galaxy, but it lacks the characteristic ‘winding’ structure. The shining red blossoms stand out as well, twisted by clouds of dust — these are the locations of intense star formation. Yet it also radiates a diffuse glow, much like an elliptical galaxy and its core of older, redder stars. This galactic marvel is known to astronomers as NGC 1156.

NGC 1156 is located around 25 million light-years from Earth, in the constellation Aries. It has a variety of different features that are of interest to astronomers. A dwarf irregular galaxy, it’s also classified as isolated, meaning no other galaxies are nearby enough to influence its odd shape and continuing star formation. The extreme energy of freshly formed young stars gives colour to the galaxy, against the red glow of ionised hydrogen gas, while its centre is densely-packed with older generations of stars.

Hubble has captured NGC 1156 before — this new image features data from a galactic gap-filling programme simply titled “Every Known Nearby Galaxy”. Astronomers noticed that only three quarters of the galaxies within just over 30 million light-years of Earth had been observed by Hubble in sufficient detail to study the makeup of the stars within them. They proposed that in between larger projects, Hubble could take snapshots of the remaining quarter — including NGC 1156. Gap-filling programmes like this one ensure that the best use is made of Hubble’s valuable observing time.



Thursday, June 02, 2022

Hubble Captures Pair of Star-Forming Spirals

IC 563/IC 564 (Arp 303)
Image Credit: NASA, ESA, K. Larson (STScI), and J. Dalcanton (University of Washington); 
Image Processing: G. Kober (NASA Goddard/Catholic University of America)

This new image from NASA’s Hubble Space Telescope looks at two spiral galaxies, collectively known as Arp 303. The pair, individually called IC 563 (bottom right) and IC 564 (top left), are 275 million light-years away in the direction of the constellation Sextans.

The image holds data from two separate Hubble observations of Arp 303. The first used Hubble’s Wide Field Camera 3 (WFC3) to study the pair’s clumpy star-forming regions in infrared light. Galaxies like IC 563 and IC 564 are very bright at infrared wavelengths and host many bright star-forming regions.

The second used Hubble’s Advanced Camera for Surveys (ACS) to take quick looks at bright, interesting galaxies across the sky. The observations filled gaps in Hubble’s archive and looked for promising candidates that Hubble, the James Webb Space Telescope, and other telescopes could study further.

The colors red, orange, and green represent infrared wavelengths taken with WFC3, and the color blue represents ACS visible light data.


Media Contacts:

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

Editor: Andrea Gianopoulos



Friday, April 08, 2022

Seeking Missing Matter in Hot Halos


Could "missing" matter be found in the extended halos of spiral galaxies? Credit: NASA, ESA and the Hubble Heritage Team (STScI/AURA);  Acknowledgment: W. Blair (STScI/Johns Hopkins University) and R. O’Connell (University of Virginia)


Many galaxies seem to have far less visible matter than expected. In a new article, astronomers have taken the search for missing matter to the outskirts of spiral galaxies.


Messier 51, the Whirlpool Galaxy, is one of the many recognizable galaxies investigated in this work. The galactic halos studied in this article likely extend hundreds of thousands of light-years into space — far larger than the galaxies’ starry disks. Messier 51’s disk is 76,000 light-years in diameter. Credit:
NASA, ESA, S. Beckwith (STScI) and the Hubble Heritage Team (STScI/AURA)

Misterious Matter

Just 15% of all the matter in the universe is thought to be visible matter — the kind we interact with on a daily basis — with dark matter making up the remaining 85%. Though dark matter is certainly the more elusive of the two, visible matter isn’t without its mysteries — after adding up the masses of the visible components of galaxies like stars and gas clouds, most galaxies appear to have less visible matter than expected based on observations of galaxies early in the universe. Milky Way-like galaxies seem to lack about 70% of their mass while low-mass galaxies can be missing all but a few percent.

Where might this missing matter be hiding? One possibility is that much of the mass of galaxies lies in extended halos that stretch hundreds of thousands of light-years beyond the bright, starry regions that make up the main body of a galaxy. This gas is difficult to detect because of its low density and interference from intervening gas within our own galaxy. How, then, can we weigh this halo gas?


A map of temperature fluctuations in the cosmic microwave background from WMAP. This map shows temperature deviations of up to 200 microkelvin. Credit: NASA


A Sunyaev–Zeldovich Stack

A team led by Joel Bregman (University of Michigan) searched for missing matter in galactic halos by looking for evidence of the Sunyaev–Zeldovich effect — the process through which low-energy photons from the cosmic microwave background are kicked up to higher energies through interactions with extremely hot gas. The magnitude of this effect is proportional to the mass and temperature of the gas, making it a useful probe of hot, diffuse halos that might otherwise be impossible to spot.

Bregman and collaborators used this method to investigate the halos around 12 spiral galaxies located 10–33 million light-years away — close enough to determine the spatial extent of the hot halo gas. Most of the halos were too faint to be detected individually, so the team stacked the observations from 11 of the 12 galaxies (one galaxy showed significant differences and was analyzed separately) to extract a signal and determine the average properties of the galaxies in the sample.


The integrated Sunyaev–Zeldovich signal from the stack of 11 galaxies as a function of radius (left) and the signal to noise ratio (right).  Credit: Bregman et al. 2022


Luminous Matter at Large

Bregman and coauthors found that out to a radius of 815,000 light-years (250 kiloparsecs), each galaxy contains 98 billion solar masses of gas. Each galaxy is expected to contain about 310 billion solar masses of visible matter, so this constitutes about 30% of the galaxies’ total mass. The galaxies’ stars, star-forming gas, and cooler halo gas make up a further 30%, meaning that the remaining 40% of the visible matter in these galaxies likely resides at even larger distances.

In order to search for gas even farther out, the team hopes to stack observations from more galaxies and develop new algorithms to reduce uncertainties. Proposed cosmic microwave background detectors like the Probe of Inflation and Cosmic Origins may also aid the search for missing matter, helping us understand where present-day galaxies hide their mass.

Citation

“Hot Extended Galaxy Halos around Local L* Galaxies from Sunyaev–Zeldovich Measurements,” Joel N. Bregman et al 2022 ApJ 928 14. doi:10.3847/1538-4357/ac51de