skip to content

Institute of Astronomy

 

NASA’s Webb Digs into Structural Origins of Disk Galaxies

Astronomy News - Fri, 27/06/2025 - 11:49
Explore Webb 5 Min Read NASA’s Webb Digs into Structural Origins of Disk Galaxies Astronomers pulled from NASA’s James Webb Space Telescope’s data to analyze a sample of 111 edge-on galaxies. The team’s analysis suggests that thick disk formation occurs first, and thin disk formation follows. Full image and caption below. Credits:
NASA, ESA, CSA, T. Tsukui (Australian National University).

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.”

Image: A Sample of Galaxy Disks (NIRCam) Astronomers pulled from NASA’s James Webb Space Telescope’s data to analyze a sample of 111 edge-on galaxies. The team’s analysis suggests that thick disk formation occurs first, and thin disk formation follows. When this process occurs depends on the galaxy’s mass. NASA, ESA, CSA, T. Tsukui (Australian National University). 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).

To learn more about Webb, visit:

https://science.nasa.gov/webb

Downloads

Click any image to open a larger version.

View/Download all image products at all resolutions for this article from the Space Telescope Science Institute.

View/Download the research results from the Monthly Notices of the Royal Astronomical Society.

Media Contacts

Laura Betz – laura.e.betz@nasa.gov
NASA’s Goddard Space Flight Center, Greenbelt, Md.

Abigail Majoramajor@stsci.edu
Space Telescope Science Institute, Baltimore, Md.

Hannah Braunhbraun@stsci.edu
Space Telescope Science Institute, Baltimore, Md.

Related Information

Article: Types of Galaxies

Video: Celestial Tour: Different types of galaxies

Article: Learn more about Webb’s views of nearby spiral galaxies

Visualization Video: Galaxy Traverse

More Webb News

More Webb Images

Webb Science Themes

Webb Mission Page

Related For Kids

What is the Webb Telescope?

SpacePlace for Kids

En Español

Ciencia de la NASA

NASA en español 

Space Place para niños

Keep Exploring Related Topics James Webb Space Telescope

Webb is the premier observatory of the next decade, serving thousands of astronomers worldwide. It studies every phase in the…


Galaxies


Galaxies Stories


Universe

Share Details Last Updated Jun 26, 2025 Editor Marty McCoy Contact Laura Betz laura.e.betz@nasa.gov Related Terms

Sparkling Andromeda

Astronomy News - Fri, 27/06/2025 - 11:49
X-ray: NASA/CXO/UMass/Z. Li & Q.D. Wang, ESA/XMM-Newton; Infrared: NASA/JPL-Caltech/WISE, Spitzer, NASA/JPL-Caltech/K. Gordon (U. Az), ESA/Herschel, ESA/Planck, NASA/IRAS, NASA/COBE; Radio: NSF/GBT/WSRT/IRAM/C. Clark (STScI); Ultraviolet: NASA/JPL-Caltech/GALEX; Optical: Andromeda, Unexpected © Marcel Drechsler, Xavier Strottner, Yann Sainty & J. Sahner, T. Kottary. Composite image processing: L. Frattare, K. Arcand, J.Major

The Andromeda galaxy, also known as Messier 31 (M31), is a glittering beacon in this image released on June 25, 2025, in tribute to the groundbreaking legacy of astronomer Dr. Vera Rubin, whose observations transformed our understanding of the universe. In the 1960s, Rubin and her colleagues studied M31 and determined that there was some unseen matter in the galaxy that was affecting how the galaxy and its spiral arms rotated. This unknown material was named “dark matter.”

M31 is the closest spiral galaxy to the Milky Way at a distance of about 2.5 million light-years. Astronomers use Andromeda to understand the structure and evolution of our own spiral, which is much harder to do since Earth is embedded inside the Milky Way.

Learn more about this image and experience in sound, too.

Image credit: X-ray: NASA/CXO/UMass/Z. Li & Q.D. Wang, ESA/XMM-Newton; Infrared: NASA/JPL-Caltech/WISE, Spitzer, NASA/JPL-Caltech/K. Gordon (U. Az), ESA/Herschel, ESA/Planck, NASA/IRAS, NASA/COBE; Radio: NSF/GBT/WSRT/IRAM/C. Clark (STScI); Ultraviolet: NASA/JPL-Caltech/GALEX; Optical: Andromeda, Unexpected © Marcel Drechsler, Xavier Strottner, Yann Sainty & J. Sahner, T. Kottary. Composite image processing: L. Frattare, K. Arcand, J.Major

‘I didn’t know someone could pursue astronomy as a career’

Astronomy News - Fri, 27/06/2025 - 11:48

Nature, Published online: 26 June 2025; doi:10.1038/d41586-025-01816-3

Astronomer Willice Obonyo describes how scholarship programmes seeded a fresh crop of radioastronomers in Africa.

Mystery fireball spotted plummeting to Earth over the US

Astronomy News - Fri, 27/06/2025 - 11:47

There have been hundreds of reports of sightings of a “fireball” in the skies over the southern US – it may have been a meteor breaking up as it falls through Earth’s atmosphere

Tue 01 Jul 11:15: The Most Ambitious Radio Astronomy Endeavour of the 21st Century? Science, Technology and Engineering Dialogues in a Large-scale Project

Next External Talks - Thu, 26/06/2025 - 15:19
The Most Ambitious Radio Astronomy Endeavour of the 21st Century? Science, Technology and Engineering Dialogues in a Large-scale Project

The presentation will open with some reflections on the early part of the Square Kilometre Array (SKA) project, where questions asked about engineering realities constraining science aspirations were raised. Early encounters between Scientists and Engineers considered Radio Frequency Interference (RFI) as one of the constraints. Some formative developments of this specific Radio Astronomy (RA) project, with a focus on the XDM , KAT7 and then MeerKAT in South Africa, will be introduced and related to unexpected RFI . The picture will then be widened to unpack an understanding of RFI and ElectroMagnetic Compatibility (EMC) for RA and science projects more generally. Two European examples will be considered. A short diversion into the language that EMC engineers use in RFI and what RA presents as uv-plane data will be taken.

Add to your calendar or Include in your list

Categories: Talks

Tue 01 Jul 11:15: Title TBC

Next External Talks - Thu, 26/06/2025 - 10:59
Title TBC

The presentation will open with some reflections on the early part of the Square Kilometre Array (SKA) project, where questions asked about engineering realities constraining science aspirations were raised. Early encounters between Scientists and Engineers considered Radio Frequency Interference (RFI) as one of the constraints. Some formative developments of this specific Radio Astronomy (RA) project, with a focus on the XDM , KAT7 and then MeerKAT in South Africa, will be introduced and related to unexpected RFI . The picture will then be widened to unpack an understanding of RFI and ElectroMagnetic Compatibility (EMC) for RA and science projects more generally. Two European examples will be considered. A short diversion into the language that EMC engineers use in RFI and what RA presents as uv-plane data will be taken.

Add to your calendar or Include in your list

Categories: Talks

The KELT-7b atmospheric thermal-inversion conundrum revisited with CHEOPS, TESS, and additional data

Recent IoA Publications - Thu, 26/06/2025 - 10:39
arXiv:2506.20432v1 Announce Type: new Abstract: Ultrahot Jupiters are predicted to show inverted temperature-pressure (T-P) profiles in the presence of optical absorbers such as TiO and VO. An inverted T-P profile of KELT-7b was recently detected, in line with these predictions, but such diagnoses are known to be model-dependent. We used CHEOPS, TESS, and literature data to characterize the atmosphere of KELT-7b, reassess its T-P profile, measure its albedo, and search for distortions in its CHEOPS transit light curve due to stellar rotation. We jointly fitted CHEOPS and TESS data to measure the occultation depths and modeled CHEOPS transits including gravity darkening. Emission and transmission retrievals were performed, and the albedo was calculated in the CHEOPS and TESS passbands. Thermochemical-equilibrium retrievals yield a non-inverted T-P profile, while free-chemistry retrievals yield an inverted profile with likely unphysical TiO/VO abundances. A 3D GCM supports a TiO-driven inversion. We report a low geometric albedo of $A_\mathrm{g} = 0.05 \pm 0.06$, consistent with inefficient heat redistribution and supported by a GCM with magnetic drag. CHEOPS data provide no constraint on the sky-projected orbital obliquity. Retrieval results strongly depend on the chemical framework. Free-chemistry fits are better but risk unphysical solutions for ultrahot Jupiters. We applied a coherent stellar variability correction to CHEOPS and TESS data; future observations would benefit from similar treatment.

The KELT-7b atmospheric thermal-inversion conundrum revisited with CHEOPS, TESS, and additional data

Instrumentation and Surveys - Thu, 26/06/2025 - 10:39
arXiv:2506.20432v1 Announce Type: new Abstract: Ultrahot Jupiters are predicted to show inverted temperature-pressure (T-P) profiles in the presence of optical absorbers such as TiO and VO. An inverted T-P profile of KELT-7b was recently detected, in line with these predictions, but such diagnoses are known to be model-dependent. We used CHEOPS, TESS, and literature data to characterize the atmosphere of KELT-7b, reassess its T-P profile, measure its albedo, and search for distortions in its CHEOPS transit light curve due to stellar rotation. We jointly fitted CHEOPS and TESS data to measure the occultation depths and modeled CHEOPS transits including gravity darkening. Emission and transmission retrievals were performed, and the albedo was calculated in the CHEOPS and TESS passbands. Thermochemical-equilibrium retrievals yield a non-inverted T-P profile, while free-chemistry retrievals yield an inverted profile with likely unphysical TiO/VO abundances. A 3D GCM supports a TiO-driven inversion. We report a low geometric albedo of $A_\mathrm{g} = 0.05 \pm 0.06$, consistent with inefficient heat redistribution and supported by a GCM with magnetic drag. CHEOPS data provide no constraint on the sky-projected orbital obliquity. Retrieval results strongly depend on the chemical framework. Free-chemistry fits are better but risk unphysical solutions for ultrahot Jupiters. We applied a coherent stellar variability correction to CHEOPS and TESS data; future observations would benefit from similar treatment.

Can tidal evolution lead to close-in planetary bodies around white dwarfs II: volcanism and transits

Recent IoA Publications - Thu, 26/06/2025 - 10:33
arXiv:2506.20316v1 Announce Type: new Abstract: Planetary material accreted by white dwarfs provides unique insights regarding exoplanetary composition. The evolutionary pathways of planetary bodies around white dwarfs are crucial to understanding the presence of close-in planetary material, observed in the form of pollutants in the atmospheres of white dwarfs and planetary material transiting white dwarfs. Periodic transits around white dwarfs potentially reveal the existence of close-in planetary bodies undergoing dust production. Tidal interactions can bring planetesimals that have been gravitationally perturbed onto long-period highly eccentric orbits around white dwarfs towards shorter orbital periods and smaller eccentricities. Tidal interactions may also induce melting and volcanism in these planetesimals, potentially being a mechanism for dust and debris production, the result of which may be seen in transit. Tidally induced volcanism may be triggered in a wide parameter space: for a 100km-sized rocky planetesimals perturbed to a pericentre distance $\lesssim$ 0.01AU ($\gtrsim$ twice its Roche limit), both on long-period (~ 100day) highly eccentric orbits and short-period (~ 10hr) near circular orbits. We comment on the potential link between the resultant volcanic ejecta and observed optical transits.

Can tidal evolution lead to close-in planetary bodies around white dwarfs II: volcanism and transits

Planetary systems - Thu, 26/06/2025 - 10:33
arXiv:2506.20316v1 Announce Type: new Abstract: Planetary material accreted by white dwarfs provides unique insights regarding exoplanetary composition. The evolutionary pathways of planetary bodies around white dwarfs are crucial to understanding the presence of close-in planetary material, observed in the form of pollutants in the atmospheres of white dwarfs and planetary material transiting white dwarfs. Periodic transits around white dwarfs potentially reveal the existence of close-in planetary bodies undergoing dust production. Tidal interactions can bring planetesimals that have been gravitationally perturbed onto long-period highly eccentric orbits around white dwarfs towards shorter orbital periods and smaller eccentricities. Tidal interactions may also induce melting and volcanism in these planetesimals, potentially being a mechanism for dust and debris production, the result of which may be seen in transit. Tidally induced volcanism may be triggered in a wide parameter space: for a 100km-sized rocky planetesimals perturbed to a pericentre distance $\lesssim$ 0.01AU ($\gtrsim$ twice its Roche limit), both on long-period (~ 100day) highly eccentric orbits and short-period (~ 10hr) near circular orbits. We comment on the potential link between the resultant volcanic ejecta and observed optical transits.

Can tidal evolution lead to close-in planetary bodies around white dwarfs I: Orbital period distribution

Planetary systems - Thu, 26/06/2025 - 10:33
arXiv:2506.20301v1 Announce Type: new Abstract: The evolution of planetary systems around white dwarfs is crucial to understanding the presence of planetary material in the atmospheres of white dwarfs. These systems uniquely probe exoplanetary compositions. Periodic signals in the photometry of a handful of white dwarfs suggest material blocking the star, potentially from disintegrating planetesimals. Tidal evolution followed by scattering can bring planetesimals onto close-in orbits that would have been within the envelope of the white dwarf progenitor. The orbital period distribution of planetesimals undergoing tidal evolution will peak at short-period (nearly) circularized orbits (~ 10 hour-1 day), with a rising tail towards long-period highly eccentric orbits (~ 100 day). This prediction is generally consistent with the observed white dwarf transiting systems. In order for the planetesimal on the 4.5 hour period around WD 1145+017 to be explained by the tidal evolution of a planetesimal, that planetesimal must have an ultimate tensile strength comparable to that of iron meteorites.

Can tidal evolution lead to close-in planetary bodies around white dwarfs I: Orbital period distribution

Recent IoA Publications - Thu, 26/06/2025 - 10:33
arXiv:2506.20301v1 Announce Type: new Abstract: The evolution of planetary systems around white dwarfs is crucial to understanding the presence of planetary material in the atmospheres of white dwarfs. These systems uniquely probe exoplanetary compositions. Periodic signals in the photometry of a handful of white dwarfs suggest material blocking the star, potentially from disintegrating planetesimals. Tidal evolution followed by scattering can bring planetesimals onto close-in orbits that would have been within the envelope of the white dwarf progenitor. The orbital period distribution of planetesimals undergoing tidal evolution will peak at short-period (nearly) circularized orbits (~ 10 hour-1 day), with a rising tail towards long-period highly eccentric orbits (~ 100 day). This prediction is generally consistent with the observed white dwarf transiting systems. In order for the planetesimal on the 4.5 hour period around WD 1145+017 to be explained by the tidal evolution of a planetesimal, that planetesimal must have an ultimate tensile strength comparable to that of iron meteorites.

An iterative CMB lensing estimator minimizing instrumental noise bias

Cosmology and Fundamental physics - Thu, 26/06/2025 - 10:24
arXiv:2506.20667v1 Announce Type: new Abstract: Noise maps from CMB experiments are generally statistically anisotropic, due to scanning strategies, atmospheric conditions, or instrumental effects. Any mis-modeling of this complex noise can bias the reconstruction of the lensing potential and the measurement of the lensing power spectrum from the observed CMB maps. We introduce a new CMB lensing estimator based on the maximum a posteriori (MAP) reconstruction that is minimally sensitive to these instrumental noise biases. By modifying the likelihood to rely exclusively on correlations between CMB map splits with independent noise realizations, we minimize auto-correlations that contribute to biases. In the regime of many independent splits, this maximum closely approximates the optimal MAP reconstruction of the lensing potential. In simulations, we demonstrate that this method is able to determine lensing observables that are immune to any noise mis-modeling with a negligible cost in signal-to-noise ratio. Our estimator enables unbiased and nearly optimal lensing reconstruction for next-generation CMB surveys.

An iterative CMB lensing estimator minimizing instrumental noise bias

Recent IoA Publications - Thu, 26/06/2025 - 10:24
arXiv:2506.20667v1 Announce Type: new Abstract: Noise maps from CMB experiments are generally statistically anisotropic, due to scanning strategies, atmospheric conditions, or instrumental effects. Any mis-modeling of this complex noise can bias the reconstruction of the lensing potential and the measurement of the lensing power spectrum from the observed CMB maps. We introduce a new CMB lensing estimator based on the maximum a posteriori (MAP) reconstruction that is minimally sensitive to these instrumental noise biases. By modifying the likelihood to rely exclusively on correlations between CMB map splits with independent noise realizations, we minimize auto-correlations that contribute to biases. In the regime of many independent splits, this maximum closely approximates the optimal MAP reconstruction of the lensing potential. In simulations, we demonstrate that this method is able to determine lensing observables that are immune to any noise mis-modeling with a negligible cost in signal-to-noise ratio. Our estimator enables unbiased and nearly optimal lensing reconstruction for next-generation CMB surveys.

Measurements of three exo-planetesimal compositions: a planetary core, a chondritic body, and an icy Kuiper belt analogue

Recent IoA Publications - Thu, 26/06/2025 - 10:13
arXiv:2506.19931v1 Announce Type: new Abstract: The study of planetesimal debris accreted by white dwarfs offers unique insights into the composition of exoplanets. Using far-ultraviolet and optical spectroscopy, we have analysed the composition of planetesimals accreted by three metal enriched H-dominated white dwarfs with effective temperatures of T_eff = 20 000 K. WD 0059+257 is accreting an object composed of 71.8 +/- 7.9 per cent Fe and Ni by mass, indicating a large core mass fraction of 69 per cent, similar to that of Mercury. We model this planetesimal as having a differentiated Earth-like composition with 65 per cent of its mantle stripped, and we find this mass loss can be caused by vaporisation of the planetesimal's mantle during post-main sequence evolution. The tentative S detection in WD 0059+257 is a possible clue to the nature of the light element in planetary cores, including that of the Earth. The volatile-rich composition of WD 1943+163 is consistent with accretion of a carbonaceous chondrite-like object, but with an extreme Si depletion. WD 1953-715 accretes a planetesimal which contains 64 +/- 21 per cent of O in the form of ices, likely H2O. This body therefore requires an initial orbit at formation beyond a radial distance of > 100 au for ice survival into the white dwarf phase. These three planetary enriched white dwarfs provide evidence of differing core fractions, volatile budgets, and initial orbital separations of the accreted planetesimals, all of which help us understand their formation and evolutionary history.

Measurements of three exo-planetesimal compositions: a planetary core, a chondritic body, and an icy Kuiper belt analogue

Planetary systems - Thu, 26/06/2025 - 10:13
arXiv:2506.19931v1 Announce Type: new Abstract: The study of planetesimal debris accreted by white dwarfs offers unique insights into the composition of exoplanets. Using far-ultraviolet and optical spectroscopy, we have analysed the composition of planetesimals accreted by three metal enriched H-dominated white dwarfs with effective temperatures of T_eff = 20 000 K. WD 0059+257 is accreting an object composed of 71.8 +/- 7.9 per cent Fe and Ni by mass, indicating a large core mass fraction of 69 per cent, similar to that of Mercury. We model this planetesimal as having a differentiated Earth-like composition with 65 per cent of its mantle stripped, and we find this mass loss can be caused by vaporisation of the planetesimal's mantle during post-main sequence evolution. The tentative S detection in WD 0059+257 is a possible clue to the nature of the light element in planetary cores, including that of the Earth. The volatile-rich composition of WD 1943+163 is consistent with accretion of a carbonaceous chondrite-like object, but with an extreme Si depletion. WD 1953-715 accretes a planetesimal which contains 64 +/- 21 per cent of O in the form of ices, likely H2O. This body therefore requires an initial orbit at formation beyond a radial distance of > 100 au for ice survival into the white dwarf phase. These three planetary enriched white dwarfs provide evidence of differing core fractions, volatile budgets, and initial orbital separations of the accreted planetesimals, all of which help us understand their formation and evolutionary history.

Evidence for a sub-Jovian planet in the young TWA 7 disk 

Astronomy News - Thu, 26/06/2025 - 10:04

Nature, Published online: 25 June 2025; doi:10.1038/s41586-025-09150-4

Using the James Webb Space Telescope's Mid-Infrared Instrument, a study reports evidence for a direct detection of a cold, sub-Jupiter-mass planet in the disk of the star TWA 7.

NASA’s Chandra Shares a New View of Our Galactic Neighbor

Astronomy News - Thu, 26/06/2025 - 10:03
6 Min Read NASA’s Chandra Shares a New View of Our Galactic Neighbor

The Andromeda galaxy, also known as Messier 31 (M31), is the closest spiral galaxy to the Milky Way at a distance of about 2.5 million light-years. Astronomers use Andromeda to understand the structure and evolution of our own spiral, which is much harder to do since Earth is embedded inside the Milky Way.

The galaxy M31 has played an important role in many aspects of astrophysics, but particularly in the discovery of dark matter. In the 1960s, astronomer Vera Rubin and her colleagues studied M31 and determined that there was some unseen matter in the galaxy that was affecting how the galaxy and its spiral arms rotated. This unknown material was named “dark matter.” Its nature remains one of the biggest open questions in astrophysics today, one which NASA’s upcoming Nancy Grace Roman Space Telescope is designed to help answer.

X-ray: NASA/CXO/UMass/Z. Li & Q.D. Wang, ESA/XMM-Newton; Infrared: NASA/JPL-Caltech/WISE, Spitzer, NASA/JPL-Caltech/K. Gordon (U. Az), ESA/Herschel, ESA/Planck, NASA/IRAS, NASA/COBE; Radio: NSF/GBT/WSRT/IRAM/C. Clark (STScI); Ultraviolet: NASA/JPL-Caltech/GALEX; Optical: Andromeda, Unexpected © Marcel Drechsler, Xavier Strottner, Yann Sainty & J. Sahner, T. Kottary. Composite image processing: L. Frattare, K. Arcand, J.Major

This new composite image contains data of M31 taken by some of the world’s most powerful telescopes in different kinds of light. This image includes X-rays from NASA’s Chandra X-ray Observatory and ESA’s (European Space Agency’s) XMM-Newton (represented in red, green, and blue); ultraviolet data from NASA’s retired GALEX (blue); optical data from astrophotographers using ground based telescopes (Jakob Sahner and Tarun Kottary); infrared data from NASA’s retired Spitzer Space Telescope, the Infrared Astronomy Satellite, COBE, Planck, and Herschel (red, orange, and purple); and radio data from the Westerbork Synthesis Radio Telescope (red-orange).

The Andromeda Galaxy (M31) in Different Types of Light.X-ray: NASA/CXO/UMass/Z. Li & Q.D. Wang, ESA/XMM-Newton; Infrared: NASA/JPL-Caltech/WISE, Spitzer, NASA/JPL-Caltech/K. Gordon (U. Az), ESA/Herschel, ESA/Planck, NASA/IRAS, NASA/COBE; Radio: NSF/GBT/WSRT/IRAM/C. Clark (STScI); Ultraviolet: NASA/JPL-Caltech/GALEX; Optical: Andromeda, Unexpected © Marcel Drechsler, Xavier Strottner, Yann Sainty & J. Sahner, T. Kottary. Composite image processing: L. Frattare, K. Arcand, J.Major

Each type of light reveals new information about this close galactic relative to the Milky Way. For example, Chandra’s X-rays reveal the high-energy radiation around the supermassive black hole at the center of M31 as well as many other smaller compact and dense objects strewn across the galaxy. A recent paper about Chandra observations of M31 discusses the amount of X-rays produced by the supermassive black hole in the center of the galaxy over the last 15 years. One flare was observed in 2013, which appears to represent an amplification of the typical X-rays seen from the black hole.

These multi-wavelength datasets are also being released as a sonification, which includes the same wavelengths of data in the new composite. In the sonification, the layer from each telescope has been separated out and rotated so that they stack on top of each other horizontally, beginning with X-rays at the top and then moving through ultraviolet, optical, infrared, and radio at the bottom. As the scan moves from left to right in the sonification, each type of light is mapped to a different range of notes, from lower-energy radio waves up through the high energy of X-rays. Meanwhile, the brightness of each source controls volume, and the vertical location dictates the pitch.

To view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 video

In this sonification of M31, the layers from each telescope has been separated out and rotated so that they stack on top of each other horizontally beginning with X-rays at the top and then moving through ultraviolet, optical, infrared, and radio at the bottom. As the scan moves from left to right in the sonification, each type of light is mapped to a different range of notes ranging from lower-energy radio waves up through the high-energy of X-rays. Meanwhile, the brightness of each source controls volume and the vertical location dictates the pitch.NASA/CXC/SAO/K.Arcand, SYSTEM Sounds (M. Russo, A. Santaguida

This new image of M31 is released in tribute to the groundbreaking legacy of Dr. Vera Rubin, whose observations transformed our understanding of the universe. Rubin’s meticulous measurements of Andromeda’s rotation curve provided some of the earliest and most convincing evidence that galaxies are embedded in massive halos of invisible material — what we now call dark matter. Her work challenged long-held assumptions and catalyzed a new era of research into the composition and dynamics of the cosmos. In recognition of her profound scientific contributions, the United States Mint has recently released a quarter in 2025 featuring Rubin as part of its American Women Quarters Program — making her the first astronomer honored in the series.

NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program. The Smithsonian Astrophysical Observatory’s Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.

Read more from NASA’s Chandra X-ray Observatory

Learn more about the Chandra X-ray Observatory and its mission here:

https://www.nasa.gov/chandra

https://chandra.si.edu

Visual Description

This release features several images and a sonification video examining the Andromeda galaxy, our closest spiral galaxy neighbor. This collection helps astronomers understand the evolution of the Milky Way, our own spiral galaxy, and provides a fascinating insight into astronomical data gathering and presentation.

Like all spiral galaxies viewed at this distance and angle, Andromeda appears relatively flat. Its spiraling arms circle around a bright core, creating a disk shape, like a large dinner plate. In most of the images in this collection, Andromeda’s flat surface is tilted to face our upper left.

This collection features data from some of the world’s most powerful telescopes, each capturing light in a different spectrum. In each single-spectrum image, Andromeda has a similar shape and orientation, but the colors and details are dramatically different.

In radio waves, the spiraling arms appear red and orange, like a burning, loosely coiled rope. The center appears black, with no core discernible. In infrared light, the outer arms are similarly fiery. Here, a white spiraling ring encircles a blue center with a small golden core. The optical image is hazy and grey, with spiraling arms like faded smoke rings. Here, the blackness of space is dotted with specks of light, and a small bright dot glows at the core of the galaxy. In ultraviolet light the spiraling arms are icy blue and white, with a hazy white ball at the core. No spiral arms are present in the X-ray image, making the bright golden core and nearby stars clear and easy to study.

In this release, the single-spectrum images are presented side by side for easy comparison. They are also combined into a composite image. In the composite, Andromeda’s spiraling arms are the color of red wine near the outer edges, and lavender near the center. The core is large and bright, surrounded by a cluster of bright blue and green specks. Other small flecks in a variety of colors dot the galaxy, and the blackness of space surrounding it.

This release also features a thirty second video, which sonifies the collected data. In the video, the single-spectrum images are stacked vertically, one atop the other. As the video plays, an activation line sweeps across the stacked images from left to right. Musical notes ring out when the line encounters light. The lower the wavelength energy, the lower the pitches of the notes. The brighter the source, the louder the volume.

News Media Contact

Megan Watzke
Chandra X-ray Center
Cambridge, Mass.
617-496-7998
mwatzke@cfa.harvard.edu

Lane Figueroa
Marshall Space Flight Center, Huntsville, Alabama
256-544-0034
lane.e.figueroa@nasa.gov

Share Details Last Updated Jun 25, 2025 EditorLee MohonContactLane Figueroa Related Terms Explore More 6 min read NICER Status Updates Article 2 days ago 2 min read Hubble Studies Small but Mighty Galaxy

This portrait from the NASA/ESA Hubble Space Telescope puts the nearby galaxy NGC 4449 in…

Article 6 days ago 3 min read NASA Scientists Find Ties Between Earth’s Oxygen and Magnetic Field

For 540 million years, the ebb and flow in the strength of Earth’s magnetic field…

Article 1 week ago

First celestial image unveiled from revolutionary telescope

Astronomy News - Thu, 26/06/2025 - 10:03

The telescope should detect killer asteroids and may even find the ninth planet in our solar system.

Rubin Observatory reveals first images

Latest News - Wed, 25/06/2025 - 15:18

The Vera C Rubin Observatory, a new scientific facility that will bring the night sky to life like never before using the largest camera ever built, has revealed its ‘first look’ images at the start of its 10-year survey of the cosmos. The Rubin Observatory , jointly funded by the US National Science Foundation and the US...