Webb and Hubble work together to reveal this spectacular pair of galaxies – and multiple bonuses!

What’s better than a pair of galaxies observed by two legendary space telescopes? The answer, according to researchers using the Hubble and James Webb Space Telescopes, lies in finding even more galaxies and other remarkable details that nobody expected in the duo’s observations.

“Foreground, background, deep background, and deep galaxies,” said Galaxy Zoo astronomer William Keel. on twitter.

“By combining data from NASA’s James Webb Space Telescope and NASA’s Hubble Space Telescope, we got more than we anticipated,” Arizona State University’s Rogier Windhorst said in a JWST blog post. Windhorst used JWST to look at the near-infrared galaxy pair VV 191 and combined it with Hubble visible and ultraviolet observations.

One of the great expectations of JWST’s commissioning was the ability to use the new telescope in conjunction with Hubble. Astronomer Helmut Jenkner of the Space Telescope Science Institute told me years ago that the two telescopes working together would be more powerful than either of them working alone.

This latest picture proves his point. The twin observations allowed astronomers to study how the dust from these two galaxies might be interacting, but it also allowed them to find other previously invisible background galaxies and even a hidden gravitational lens.

“This is all from 30 minutes of data using 1/8th the field of view of JWST’s NIRCam camera,” Keel mused. “And there are many more galaxies [like these] out there.”

dusty questions

Dust is one of the most important components of the universe, as it plays an important role in the evolution of galaxies and is an essential ingredient for new stars and planets. Analysis of intergalactic and cosmic dust can provide snapshots of the contents, conditions and processes occurring in galaxies – and even in other solar systems – at various stages of their evolution.

Because JWST is an infrared telescope, one of the fundamental applications of the new telescope is to learn more about the properties of dust in other galaxies as well as in our own galaxy. Infrared telescopes have the ability to peer into the dust to determine its properties.

With that in mind, VV 191 has been targeted as an early observation for JWST based on how galactic pairs offer rare insights and unique opportunities to study galactic dust. Volunteers from the citizen scientist/community scientist project Galaxy Zoo have been recruited to contribute to a catalog of nearly 2,000 eligible pairs of galaxies. VV 191 was first noticed by a zoo volunteer in 2007.

In a Galaxy Zoo blog post, Keel wrote that silhouetted or overlapping galaxy systems “can highlight the effects of dust in the foreground galaxy on passing light and provide opportunities to study the dust that complement observations in the deep infrared, where the dust itself shines and gives.” the energy it absorbs from starlight.”

While Hubble’s visible-light measurements of these types of backlit galaxies tell us where the dust is — no matter how cold it may be (and where it may be hiding from infrared detection), the new infrared data from JWST allowed the researchers to find out , how the interstellar dust affects the spiral galaxy.

They were able to track the light emitted by the bright white elliptical galaxy – the left – which “backlit” the spiral galaxy, allowing them to see the effects of interstellar dust through the twisting spiral galaxy on the right pursue.

“Understanding where dust is present in galaxies is important because dust changes the brightness and colors that appear in images of the galaxies,” Windhorst said. “Dust grains are partly responsible for the formation of new stars and planets, so we always try to identify their presence for further study.”

These two galaxies could look like they’re intertwining or colliding — and were once thought to be. But the new observations with JWST show that they are actually quite distant and not actively interacting. You can see how the dusty, reddish arms of the spiral galaxy on the right look like they’re overlapping the white ellipse on the left. Astronomers said if you could look at an angle there would be a noticeable distance between them.

But wait, there’s more!

However, other things emerged in the new JWST observations. A previously invisible galaxy appeared – twice! Look again at the white elliptical trainer. A faint red arc appears in the inset at 10 o’clock. Light from a very distant galaxy is bent and magnified by the gravity of the elliptical galaxy in the foreground – and its image is duplicated. The stretched red arc is distorted where it reappears – as a dot – at 4 o’clock.

“These images of the lens galaxy are so faint and so red that they were not detected in Hubble data,” Windhorst wrote, “but they are unmistakable in Webb’s near-infrared image. Simulations of galaxies with gravitational lenses like this one help us to reconstruct how much mass individual stars have and how much dark matter is in the core of this galaxy.”

As we said earlier, every JWST image is essentially like a Hubble Deep Field image. So zoom in to see the array of distant galaxies. For example, two patchy spirals in the upper left of the elliptical galaxy have similar apparent sizes but appear very different colors. One is likely very dusty and the other very distant, but the researchers said they need to get data known as spectra to determine which is which.

Here you can read the full description and download the annotated image files.

Furious …. all of this from a brief observation by JWST, supplemented with Hubble data.

In short, Keel said, “We got what we came for and the universe provided interesting bonuses.”

Further reading and related academic work: