Interacting galaxies are more than they seem, JWST shows

Just two years ago, the first scientific images of JWST were released.

This image shows the difference between the NIRCam and MIRI images of JWST, with the NIRCam being much sharper and detecting more objects. The MIRI image reveals details of dust that no other wavelength can, however, including the abundance and composition of the dust inside, which correlates to a galaxy’s potential for stars and life to form. In MIRI view, red = gas rich; blue = gas poor (but still present); green = organic molecules, especially polycyclic aromatic hydrocarbons.

Credit: NASA, ESA, CSA and STScI

They combined high resolution with unprecedented sensitivity in infrared light.

Overlaid with (older) Hubble data, the JWST NIRCam image of the Southern Ring Nebula is clearly superior in several ways: resolution, revealed detail, extent of outer gas, etc. It’s a truly spectacular discovery of how stars like the Sun end their lives, and how, very slightly, the nebula has expanded between the Hubble and JWST image acquisitions.

Credit: NASA, ESA, CSA and STScI

There have been many surprises since the beginning.

the quintet of Stephan miri JWST

This image is the first mid-infrared image of the Stephanian Quintet ever taken by the James Webb Space Telescope. The galaxy in the upper right of the image displays a brilliant spiky pattern: evidence of a never-before-detected supermassive black hole.

Credit: NASA, ESA, CSA, STScI

New features were discovered within planetary systems.

Fomalhaut JWST system

This image of the dusty debris disk surrounding the young star Fomalhaut is from the Webb Intermediate Infrared Instrument (MIRI). It reveals three nested belts extending 14 billion miles (23 billion kilometers) from the star. The inner belts – which had never been seen before – were discovered by Webb for the first time. The labels on the left indicate the individual features. On the right, a large dust cloud is highlighted and the pull-ups show it at two infrared wavelengths: 23 and 25.5 microns.

Credit: NASA, ESA, CSA; Editing: A. Gáspár (University of Arizona) & Alyssa Pagan (STScI)

Distance records were broken, both for individual galaxies,

JADES-GS-z14-0, in the upper inset, lies behind (and just to the right of) a closer, brighter, bluer galaxy. Only through the power of extraordinary resolution spectroscopy, capable of separating the two sources, could the nature of this distant record object be determined. Its light comes to us from when the Universe was only 290 million years old: only 2.1% of its current age.

Credit: S. Carniani et al. (JADES collaboration), arXiv:2405.18485, 2024

as well as the earliest galaxy clusters.

JWST most distant galaxy cluster

Galaxies that are members of the proto-cluster identified as A2744z7p9OD are shown here, superimposed on their positions in the JWST view of the galaxy cluster Abell 2744. Just 650 million years after the Big Bang, it is the oldest proto-cluster of galaxies ever identified. This is early, but is consistent with simulations of when the earliest proto-clusters should emerge from the initially denser regions.

Credit: NASA, ESA, CSA, Takahiro Morishita (IPAC); Editing: Alyssa Pagan (STScI)

But spectacular features also appeared within interacting galaxies.

JWST Background of galaxies Stephan's Quintet

Stellar streams breaking off from one of the interacting member galaxies of Stephan’s Quintet shine in this image, while background galaxies shine from much further away. The young stars that form may not remain gravitationally bound and undisturbed for long, but as long as they persist, they will form collections of stars (or galaxies) that have no dark matter inside them at all.

Credit: NASA, ESA, CSA and STScI

With NIRCam near-infrared and MIRI mid-infrared views, optically invisible features shone brightly.

The pair of interacting galaxies in the process of a merger, known as IC 1623, is imaged here by JWST. Data from a trio of JWST instruments, MIRI, NIRSpec and NIRCam, were used to construct this image. The continuous bursting of stars in the center produces intense infrared emissions.

Credit: ESA/Webb, NASA & CSA, L. Armus & A. Evans; Credit: R. Colombari

Previously, the galactic pair Arp 142 – the Penguin and the Egg – was seen by Hubble.

This pair of interacting galaxies, cataloged as Arp 142, was named “The Penguin and the Egg” after the Hubble Space Telescope revealed this view of two member galaxies: the expanded NGC 2936 and the compact NGC 2937.

Credit: NASA, ESA and the Hubble Legacy Team (STScI/AURA)

To celebrate its second anniversary, JWST released a NIRCam image,

This NIRCam view of Penguin and Egg shows a smoky appearance, while Penguin’s “eye” glows brightly: corresponding to the center of what was, until perhaps 75 million years ago, just a normal-looking spiral galaxy. . The gravitational encounter with the “Egg” galaxy has warped and expanded the less massive spiral galaxy into the form now seen here.

Credit: NASA, ESA, CSA, STScI

a GOOD image,

In mid-infrared light, Penguin looks more like a seahorse, with cool dust dominating the galaxy’s view, while the Egg looks smaller and more compact: lit mainly by the cooler, older stars of present within it. At wavelengths much longer than the NIRCam image, MIRI’s resolution is much lower, but it still reveals spectacularly sharp features.

Credit: NASA, ESA, CSA, STScI

and also a composite image of this galactic encounter, occurring 326 million light years away.

In this composite image, the NIRCam and MIRI data are combined together to produce this image, which is richer in detail than the NIRCam or MIRI images alone. While both MIRI and NIRCam features are clearly present throughout Penguin, only the central core of the Egg has a MIRI contribution.

Credit: NASA, ESA, CSA, STScI

The largest galaxy, Penguin, exhibits highly extended features: knotted gas, which triggers new episodes of star formation.

This three-panel animation shows Hubble (visible light), NIRCam (near-infrared light), and NIRCam+MIRI (all JWST light) images superimposed on each other, highlighting the different features present within the Penguin component of Arp 142.

Credits: NASA, ESA and the Hubble Legacy Team (STScI/AURA); NASA, ESA, CSA, STScI; Editing: E. Siegel

The egg, meanwhile, is relatively undisturbed: a more massive, compact elliptical galaxy with very little gas left.

This three-panel animation shows Hubble (visible light), NIRCam (near-infrared light), and NIRCam+MIRI (all JWST light) images superimposed on each other, highlighting the various features present within the Egg component of Arp 142. Note how only the background galaxies and the absolute center of the Egg are affected by the MIRI images.

Credits: NASA, ESA and the Hubble Legacy Team (STScI/AURA); NASA, ESA, CSA, STScI; Editing: E. Siegel

Nearby, the edge galaxy PGC 1237172 is 100 million light-years closer: dust-poor and almost invisible for GOOD.

This three-panel animation shows Hubble (visible light), NIRCam (near-infrared light), and NIRCam+MIRI (all JWST light) images superimposed on each other, highlighting the various features present within the edge galaxy PGC 1237172. The galaxy itself is almost invisible to MIRI’s eyes.

Credits: NASA, ESA and the Hubble Legacy Team (STScI/AURA); NASA, ESA, CSA, STScI; Editing: E. Siegel

The penguin, once a spiral, lies in a seahorse-like appearance in infrared light.

These three views show the visible (left), near-infrared (middle), and mid-infrared (right) light of the Penguin galaxy that is part of Arp 142. The galaxy takes on a seahorse-like appearance in mid-light infrared, such as polycyclic aromatic hydrocarbons, old, cold stars and cold dust are highlighted.

Credits: NASA, ESA and the Hubble Legacy Team (STScI/AURA); NASA, ESA, CSA, STScI; Composition: E. Siegel

The smoke-like appearance reveals polycyclic aromatic hydrocarbons: complex organic molecules that may be precursors to life.

This JWST-annotated composite view shows NIRCam and MIRI data together, highlighting longer-wavelength features in redder colors and shorter-wavelength ones in bluer colors. Penguin, in particular, exhibits a large variety of gaseous and stellar features, indicating how severely it is being disrupted by this gravitational encounter.

Credit: NASA, ESA, CSA, STScI

Eventually, and ironically, the Egg will subdue the Penguin.

Mostly Mute Monday tells an astronomical story in images, visuals and no more than 200 words.

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