Hubble, JWST together reveal vivid landscape of galaxies

ASU researchers contribute to studies examining the infrared light from the images

November 9, 2023

Webb and Hubble have joined forces to study the galaxy cluster MACS0416, located about 4.3 billion light-years from Earth.

Their combined data yields a colorful panorama of blues and reds — colors that give clues to the distances of the galaxies. The resulting panchromatic image combines visible and infrared light to assemble one of the most comprehensive views of the universe ever taken.  The various colors and lights of a galaxy. This panchromatic view of galaxy cluster MACS0416 was created by combining infrared observations from NASA’s James Webb Space Telescope with visible-light data from NASA’s Hubble Space Telescope. Image: MACS 0416 Webb and Hubble. Image courtesy NASA, STScI, ASU Download Full Image

On its own, the image itself is stunning. Researchers are already using these observations to fuel new scientific discoveries, including identifying gravitationally magnified supernovae and otherwise invisible, ordinary stars.

The image reveals a wealth of details that are only possible by combining the power of both space telescopes. It includes a bounty of galaxies outside the cluster and a sprinkling of sources that vary over time, likely due to gravitational lensing — the distortion and amplification of light from distant background sources.

This cluster was the first of a set of unprecedented, super-deep views of the universe from an ambitious, collaborative Hubble program called the Frontier Fields, inaugurated in 2014. Hubble pioneered searching for some of the intrinsically faintest and youngest galaxies ever detected. Webb's infrared view significantly bolsters this deep look by going even farther into the early universe with its infrared vision.

The pair of papers describing the discovery of the new time-domain discoveries in the infrared, which has been published in The Astrophysical Journal and Astronomy & Astrophysics, is led by Haojing Yan of the University of Missouri in Columbia and Jose Diego of the Instituto de Física de Cantabria in Spain, and includes Arizona State University co-authors Rogier Windhorst, Seth Cohen, Rolf Jansen and Jake Summers.

"We are building on Hubble's legacy by pushing to greater distances and fainter objects," said Windhorst, a Regents Professor and astronomer at ASU's School of Earth and Space Exploration and principal investigator of the PEARLS program (Prime Extragalactic Areas for Reionization and Lensing Science), which took the Webb observations. 

What the colors mean

To make the image, in general, the shortest wavelengths of light were color-coded blue, the longest wavelengths red, and the intermediate wavelengths green. The range of wavelengths, from 0.4 to 5 microns, yields a particularly vivid landscape of galaxies. 

Those colors give clues to galaxy distances: The bluest galaxies are relatively nearby and often show intense star formation, as best detected by Hubble. In contrast, the redder galaxies tend to be more distant, as detected by Webb. Some galaxies also appear very red because they contain copious amounts of cosmic dust that tends to absorb bluer colors of starlight.

"The whole picture doesn't become clear until you combine Webb data with Hubble data," Windhorst said.

side by side comparisons of galaxy images

This side-by-side comparison of galaxy cluster MACS0416 as seen by the Hubble Space Telescope in optical light (left) and the James Webb Space Telescope in infrared light (right) reveals different details. Both images feature hundreds of galaxies, however, the Webb image shows galaxies that are invisible or only barely visible in the Hubble image. Photo credit: NASA, ESA, CSA, STScI

Christmas Tree Galaxy Cluster

While the new Webb observations contribute to this aesthetic view, they were taken for a specific scientific purpose. The research team combined their three epochs of observations, each taken weeks apart, with a fourth epoch from the CANUCS (Canadian NIRISS Unbiased Cluster Survey) research team.

The goal was to search for objects varying in observed brightness over time, known as transients.

“By re-imaging the same cluster multiple times, we knew we would find some interesting objects beyond what the spectacular single epoch image showed, and these observations exceeded our expectations,” said Cohen, associate research scientist at ASU. 

They identified 14 such transients across the field of view. Twelve of those transients were located in three galaxies that are highly magnified by gravitational lensing and are likely to be individual stars or multiple-star systems that are briefly very highly magnified. The remaining two transients are within more moderately magnified background galaxies and will likely be supernovae.

"We're calling MACS0416 the Christmas Tree Galaxy Cluster, both because it's so colorful and because of these flickering lights we find within it. We can see transients everywhere," said Yan, an ASU PhD graduate who is now at the University of Missouri in Columbia and lead author of one paper describing the scientific results.

Finding so many transients with observations spanning a relatively short time frame suggests that astronomers could find many additional transients in this cluster and others like it through regular monitoring with Webb.

“Together with massive galaxy clusters, acting as nature’s magnifying glass, JWST has proven to be an extremely powerful instrument for studying transients and variable sources of astrophysical and cosmological interest,” said Jansen, a senior research scientist at ASU.

Video by Steve Filmer/ASU

A kaiju star

Among the transients the team identified, one stood out in particular. Located in a galaxy that existed about 3 billion years after the Big Bang, it is magnified by a factor of at least 4,000.  

The team nicknamed the star system "Mothra" in a nod to its "monster nature," being both extremely bright and extremely magnified. It joins another lensed star the researchers previously identified that they nicknamed "Godzilla." (Both Godzilla and Mothra are giant monsters known as kaiju in Japanese cinema.)

"The extreme resolution of the Webb images allow us to probe the lensed arcs of galaxy clusters for transients such as Mothra," said Summers, an undergraduate research aide at ASU.

Interestingly, Mothra is also visible in the Hubble observations that were taken nine years previously. This is unusual because a very specific alignment between the foreground galaxy cluster and the background star is needed to magnify a star so greatly. The mutual motions of the star and the cluster should have eventually eliminated that alignment.

The most likely explanation is that there is an additional object within the foreground cluster that is adding more magnification. The team was able to constrain its mass to be between 10,000 and 1 million times the mass of our sun. The exact nature of this so-called "milli-lens," however, remains unknown.

"The most likely explanation is a globular star cluster that's too faint for Webb to see directly," said Diego, lead author of the paper detailing the finding. "But we don't know the true nature of this additional lens yet."

The Webb data shown here were obtained as part of PEARLS GTO program 1176

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, the European Space Agency and the Canadian Space Agency.

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

For more information and to download the released high-resolution images, please visit

This press release was written by Christine Pulliam Space Telescope Science Institute, with contributions from Kim Baptista from ASU's School of Earth and Space Exploration.

Media Relations and Marketing Manager, School of Earth and Space Exploration


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ASU well represented in 2024 NEA Big Read Program

November 9, 2023

Professors Natalie Diaz and Alberto Ríos and alum Tayari Jones had their works chosen

Two Arizona State University professors and a Sun Devil alum are among 50 writers who have had their literary works chosen to be part of the 2024 National Endowment of the Arts Big Read program.

ASU Regents Professor Alberto Ríos, English Professor Natalie Diaz and alum Tayari Jones have joined distinguished writers such as Ray Bradbury, Jack London, Toni Morrison and Amy Tan in the program, which provides financial support to selected nonprofit organizations around the country so they can host communitywide reading events.

Organizations apply for funding through a grants program, and each community that receives a grant — the grants range from $5,000 to $20,000 — hosts a Big Read author for an event such as a book fair, a reading, writing workshops, etc.

(The grant process for 2024 is ongoing, so Ríos, Diaz and Jones have yet to be contacted by communities.)

“To me, the Big Read is really the gold standard of community reads because it defines community so broadly,” said Jones, who graduated from ASU in 2000 with a Master of Fine Arts in creative writing and whose book, “Silver Sparrow,” already was part of a Big Read event in 2016 in Peoria, Illinois. “If a city or a town chooses this book, this book is for everyone. There are no boundaries to sharing this story. And that is really what literature does. It brings us together around a common story, and we share our opinions, and we share our experiences, and we experience vicariously.”

ASU News talked to Jones, Ríos and Diaz about their works and the honor of being chosen as part of the Big Read Program.

Portrait of woman with long dark hair wearing a baseball style tee

Natalie Diaz

Natalie Diaz: "Postcolonial Love Poem"

Question: What does it mean for you to have your book of poems included in the program?

Answer: I’m lucky to be part of such a wonderful program. NEA Big Reads works so hard to put books in the hands of so many different communities, some of whom are often overlooked or forgotten, or who don’t have funding to create public events around books. These grants also reward art-makers, by giving them funding to support their incredible imaginations and the care they have for books.

Q: Can you give me an overview of your book, "Postcolonial Love Poem"?

A: This is the book I needed to write, a language that allows me to exist fully and abundantly, in wonder and imagination, as a physical body who is of consequence to the world, a small momentum in a larger tradition of story that connects us all to the land and water. The book imagines everybody as the body of the beloved — rivers, deserts, lovers, family, enemies, strangers. It uses light as a way of moving and touching and beholding this beautiful world, even in its pains and violences. It is a group of poems that lets me be more than a victim of colonialism and allows me to be a part of what this world might become of love and dream and tenderness.

Q: Why do you think the Big Read program is important?

A: NEA Big Read elevates story as a main connector of what makes us human. It creates events across diverse communities and centers many diverse perspectives that help the books live in ways the writer might never have imagined, as all good stories do.

Portrait of Black woman with medium length dark, curly hair

Photo of Tayari Jones by Beowulf Sheehan

Tayari Jones: "Silver Sparrow"

Q: You were part of a Big Read event in 2016. What was that like?

A: That was when I really got to see the reach of the program, because the idea of the Big Read is to get whole communities organized around a single book. One of the things they did in Peoria was that they put copies of the book in food boxes at the food pantry where I did the event. It just showed me how people want to read. People enjoy stories no matter who they are.

Q: Your book is about two girls coming of age, right?

A: It’s the story of two girls, Dana and Chaurisse. They have the same father, but they have different mothers. They’re the same age because, as the first line of the novel says, “My father, James Witherspoon, is a bigamist.” It’s about the man, his two daughters and it’s about class. It’s about legitimacy and what does that mean? And it’s really about mothers and daughters.

Q: With this program, the NEA is basically encouraging reading. Is that how you see it?

A: Not only does it encourage reading, but by having the imprimatur of the NEA, it says, “Hey, this is a book you can bring into your schools. This is a book you can bring into your communities.” It’s almost like the NEA has vetted these books and has said they’re officially stories of the American experience.

Portrait of man with short gray hair wearing glasses

Alberto Ríos

Alberto Rios: "A Small Story About the Sky"

Q: What is your poem about?

A: It’s all about community. It’s about Arizona. It’s about the desert. There’s a lot of eco poetics in it. A lot of cultural references. The poem was kind of prompted by the deaths of the Yarnell firefightersNineteen wildland firefighters with the Granite Mountain Hotshots crew were killed on June 30, 2013. in Arizona. The poem is not about them specifically, but it is about fire and the sky. It sort of comes out of that Arizona experience of grief that we all went through when those firefighters died. My brother was a firefighter — he’s retired now — so it hit slightly closer to home. I could have written about the firefighters, and that would have gotten a lot of attention, but I wanted to find something new that’s right in front of us. I think that’s the job of poetry, to show us this normalized thing in a brand new way and make us feel something as a result of that. I think art’s job in so many ways is to move us from where we’re standing to what we’re feeling.

Q: Why is this program effective in bringing people together?

A: I think it becomes very, very specific to the community. They’re looking for particular kinds of works that are, if not aimed, certainly play a part in community building, are about communities and speak to that familial feeling, what I call the kitchen table. That’s what they’re shooting for, and I think I’m lucky to have my work reflect that.

Q: You’ve been part of the program before. What was that experience like?

A: I had one community where they took their poems, and they had a group of painters. This was their idea, which was brilliant. They had a group of painters who painted their version of these different poems that were read. I thought, “What a wonderful way to think about it." It wasn’t just done with writing.

Scott Bordow

Reporter , ASU News