#galaxy clusters

[thepastisalreadywritten]

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Chandra, named in honor of the late Indian American astrophysicist Subrahmanyan Chandrasekhar, launched to space aboard the space shuttle Columbia on 23 July 1999.

The crew, including STS-93 Commander Eileen Collins, deployed the telescope into its oval-shaped orbit, which takes Chandra on a path around Earth that is nearly one-third of the distance to the moon.

So far, Chandra has taken nearly 25,000 observations of the universe.

The telescope observes the cosmos through X-ray light, which is invisible to the human eye.

X-rays are released by some of the most energetic events and hottest objects in the universe, including exploded stars, material swirling around black holes, galactic collisions and even exoplanets.

Chandra plays a key role not only as an X-ray telescope but in providing data that pairs with observations from other telescopes.

Combined, all of those wavelengths of light provide a more complete picture that enables astronomers to solve the universe’s lingering mysteries.

24 July 2024

[livingforstars]

Giant Cluster Bends, Breaks Galaxy Images - April 24th, 1996.

"What are those strange blue objects? Many are images of a single, unusual, beaded, blue, ring-like galaxy which just happens to line-up behind a giant cluster of galaxies. Cluster galaxies here appear yellow and - together with the cluster's dark matter - act as a gravitational lens. A gravitational lens can create several images of background galaxies, analogous to the many points of light one would see while looking through a wine glass at a distant street light. The distinctive shape of this background galaxy - which was probably just forming - has allowed astronomers to deduce that it has separate images at 4, 8, 9 and 10 o'clock, from the center of the cluster. Possibly even the blue smudge just left of the center is yet another image! This spectacular photo from HST was taken in October, 1994. The first cluster lens was found unexpectedly by Roger Lynds (NOAO) and Vahe Petrosian (Stanford) in 1986, while testing a new type of imaging device. Lensed arcs around this cluster, CL0024+1654, were first discovered from the ground by David Koo (UCO Lick) in 1988."

[netmassimo]

An article published in the journal "The Astrophysical Journal" reports the results of a study on the ongoing merger between two galaxy clusters that are forming a single new cluster cataloged as MACS J0018.5+1626, or simply MACS J0018.5. A team of researchers used data obtained from observations dating back even decades conducted with various space and ground-based telescopes, analyzing them to decouple the behavior of ordinary matter and dark matter.

To measure the speed of intergalactic gas composed of normal matter, they used the kinematic Sunyaev-Zel'dovich (SZ) effect. The speed of dark matter is roughly the same as galaxies. The result is that dark matter moves faster than normal matter. This result offers clues about dark matter and its behavior that are useful in studies of its nature.

[mindblowingscience]

In a recent study published in Monthly Notices of the Royal Astronomical Society, a team led by physicists at the Department of Energy's SLAC National Accelerator Laboratory and Stanford University made detailed measurements of the X-ray emission from galaxy clusters, which revealed the distribution of matter within them. In turn, the data helped the scientists test the prevailing theory of the structure and evolution of the universe, known as Lambda-CDM.

Getting there wasn't an easy task, however.

Here's the trouble: Inferring the mass distributions of galaxy clusters from their X-ray emission is most reliable when the energy in the gas within clusters is balanced by the pull of gravity, which holds the whole system together. Measurements of the mass distributions in real clusters therefore focus on those that have settled down to a "relaxed" state. When comparing to theoretical predictions, it is therefore essential to take this selection of relaxed clusters into account.

Keeping this in mind, Stanford physics graduate student Elise Darragh-Ford and her colleagues examined computer-simulated clusters produced by the The Three Hundred Project. First, they computed what the X-ray emission for each simulated cluster should look like. Then, they applied the same observational criteria used to identify relaxed galaxy clusters from real data to the simulated images to winnow the set down.

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[merelygifted]

Hubble telescope captures the making of a 'cosmic monster' (photo) | Space

The massive cluster of galaxies lies about 8 billion light-years from Earth

The Hubble Space Telescope captured a massive cluster of galaxies, called eMACS J1353.7+4329, located about eight billion light-years from Earth in the constellation Canes Venatici. (Image credit: ESA/Hubble & NASA, H. Ebeling)

A "cosmic monster" is growing in a distant corner of the universe, and we just got a look at it.

The Hubble Space Telescope captured a stunning new view of a massive galaxy cluster called eMACS J1353.7+4329. This cluster lies about eight billion light-years from Earth in the constellation Canes Venatici. (For perspective, the farthest object ever observed lies 13.5 billion light-years from Earth.)

This galaxy cluster is "a monster in the making," consisting of at least two elliptical galaxy clusters in the process of merging together, according to a statement from the European Space Agency. (Hubble is a joint mission of NASA and ESA.)  ...

[calorionsstarchive]

Big bear pair (ngc 3718/3729)

[frank-olivier]

Unveiling the Cosmic Dance: From Milkomeda to Laniakea, Across the Vast Void

The vastness of the universe is impressive. It consists of billions of galaxies that extend over billions of light years. But within this immense expanse, our cosmic neighborhood, the so-called local universe, has a special significance. Here we find our home galaxy, the Milky Way, and countless other celestial bodies that shape our understanding of the cosmos. Let's embark on a journey through the local universe and explore the fascinating structures of galaxy groups, clusters and superclusters and their role in the larger structure of the cosmos.

Our immediate cosmic family is the Local Group, a collection of galaxies held together by gravity. This small-scale structure consists of the Milky Way, the Andromeda Galaxy (M31), the Triangulum Galaxy (M33), and about 50 dwarf galaxies. Although the Local Group may seem insignificant compared to the vastness of the Universe, it is a crucial laboratory for studying galaxy interactions and dynamics.

The Andromeda Galaxy, our nearest large star neighbor, is a stunning sight in the night sky. With its spiral arms and bright core, M31 is a prominent feature of the constellation Andromeda. The May 10, 2009 Astronomy Picture of the Day shows M31 and its companion, the elliptical galaxy M32, providing a stunning visual representation of the beauty and complexity of the Local Group.

One of the most fascinating aspects of the Local Group is the future collision between the Milky Way and the Andromeda Galaxy. In about 4.5 billion years, these two majestic galaxies will merge and form a new entity called "Milkomeda." This cosmic event highlights the dynamic nature of galactic interactions and the ever-evolving nature of our local Universe.

As we expand our view beyond the Local Group, we encounter larger and more diverse structures - galaxy groups and clusters. These are collections of galaxies held together by the gravitational forces that shape the Universe. Galaxy groups and clusters come in different sizes and densities, and each offers unique insights into the evolution and behavior of galaxies.

Paul Hickson identified Hickson Compact Groups as small, dense collections of galaxies. These groups are of particular interest because of their potential for galaxy mergers and interactions. In such a small space, galaxies can be subject to tidal forces, gas ejection and gravitational perturbations, leading to the formation of new types of galaxies and the reshaping of existing ones.

The Virgo Cluster is a prominent galaxy cluster in the local Universe, located in the constellation Virgo. It is a rich cluster containing thousands of galaxies, including giant elliptical galaxies and numerous spiral galaxies. The Virgo Cluster is a prime example of how galaxies gather and interact in a dense environment, influencing each other's evolution.

Rich galaxy clusters are cosmic giants containing thousands to tens of thousands of galaxies and huge amounts of hot gas. These clusters are not only impressive in size, but also crucial for understanding the distribution of matter in the universe and the role of dark matter.

The Coma Cluster in the constellation Coma Berenices is a remarkably rich galaxy cluster. It is one of the most distant objects visible to the naked eye and contains a diverse population of galaxies. The high density of galaxies and the hot gas within the cluster make the Coma Cluster an ideal laboratory for studying cluster dynamics and the effects of gravitational interactions on galaxy evolution.

The Abell Catalog, compiled by astronomer George Abell, is a comprehensive list of rich galaxy clusters. Named after their discoverer, these clusters are crucial for mapping the large-scale structure of the Universe. Abell clusters such as Abell 02352 and Abell 03496 (the Hercules Cluster) are massive structures that contribute significantly to our understanding of the cosmic web.

A critical aspect of galaxy clusters is the presence of dark matter, a mysterious and invisible substance that makes up most of the mass of these structures. The gravitational influence of dark matter is enormous, as it holds galaxies together in clusters and superclusters. In fact, most of the mass in galaxy clusters is dark matter, making it a dominant force in shaping the cosmic landscape.

The hot gas in dense galaxy clusters, the so-called intracluster medium, is a remarkable feature. Heated to millions of degrees, this gas emits X-rays that can outshine the light from individual galaxies. Studying this X-ray-emitting gas provides valuable insights into the temperature, density and overall mass distribution of the cluster. It is a powerful tool for astronomers to study the invisible dark matter and understand the dynamics of these massive structures.

As we travel through the local universe, we encounter superclusters, the largest known structures in the cosmos. Superclusters are vast collections of galaxy groups and clusters connected by galaxy filaments. They are the building blocks of the cosmic web, the complex network that spans the entire observable universe.

The Virgo Supercluster is our home supercluster, which contains the Local Group and the Virgo Cluster. It is a massive structure that spans 100 million light-years, making it a significant landmark in our cosmic neighborhood. The Virgo Supercluster is a crucial part of the larger Laniakea Supercluster, which defines our place in the cosmic web.

In 2014, astronomers defined the boundaries of the Laniakea Supercluster, a massive structure that encompasses and extends far beyond the Virgo Supercluster. Laniakea, which means "immeasurable sky" in Hawaiian, represents our cosmic home on a grand scale. Understanding superclusters like Laniakea is critical to mapping the large-scale structure of the universe and our place in it.

When we zoom in to even larger scales, we encounter the most extensive structures in the universe, including voids, filaments, and walls. These features form the cosmic web, a complex network that defines the distribution of matter in the universe.

Voids are vast, empty regions of space with few or no galaxies. They are the cosmic deserts separated by the complex filaments and walls of the cosmic web. Voids can extend for hundreds of millions of light years and are crucial for understanding the large-scale structure and evolution of the universe.

Filaments are long, thin structures that connect galaxy clusters and superclusters, while walls or sheets are relatively flat structures that contain numerous galaxies. These features form a cosmic fabric that determines the distribution of galaxies and superclusters. The "Great Wall" of Sloan, discovered by the Sloan Digital Sky Survey (SDSS), is a remarkable example of a huge sheet of galaxies that stretches for a billion light-years.

The Sloan Digital Sky Survey is a groundbreaking astronomical project that has revolutionized our understanding of the local universe and the cosmic web. SDSS has mapped the positions and distances of millions of galaxies, creating a detailed three-dimensional map of the cosmos. This survey has been crucial in identifying galaxy clusters, superclusters, and the complex filaments and voids that make up the cosmic web.

The local universe is a vibrant and dynamic environment filled with galaxies, groups, clusters, and superclusters. From the intimate interactions within the local group to the vast structures of the cosmic web, each element contributes to the grand narrative of the universe's evolution. Exploring the local universe allows us to understand our place in the cosmos and the complex relationships between celestial bodies. Studying galaxy groups, clusters, and superclusters provides valuable insights into the distribution of matter, the nature of dark matter, and the large-scale structure of the universe. As we continue to push the boundaries of astronomical research, the local universe will remain a crucial laboratory for testing our theories and expanding our knowledge of the cosmos. By unlocking the mysteries of our cosmic neighborhood, we come one step closer to understanding the vast and wondrous universe we inhabit.

Groups and Clusters of Galaxies (Jason Kendall, April 2024)

Where is Everything in The Universe Going? (History of the Universe, October 2024)

Sunday, October 13, 2024

[the-wolf-and-moon]

NGC 602, Star Cluster

[spacewonder19]

 Stars in the open cluster Trumpler 14 ©

[without-ado]

Westerlund 1, 12000 lys away l Webb

[assassin1513]

◾️▪️🖤Punk Space🖤▪️◾️

[spacevoyagerx]

Globular Cluster

NGC 6355 is a globular cluster located in the constellation Ophiuchus. It is one of the many globular clusters that orbit the Milky Way galaxy.

Globular clusters are dense collections of stars, typically containing hundreds of thousands to millions of stars, all bound together by gravity.

It is less than 50,000 light-years from Earth.

Credits: ESA/Hubble & NASA, E. Noyola, R. Cohen

[livingforstars]

Watch Galaxies Form - September 5th, 1996.

"Snips and snails and puppy dog tails, is that what galaxies were made of? Astronomers imaged an interesting distant patch of sky with the orbiting Hubble Space Telescope. They found many merging groups of stars and gas which have been dubbed "pre-galactic blobs." A particularly dense bunch of these small blue merging objects are visible in the above picture. This may be a snapshot of galaxies actually being formed! Although peculiar by present standards of galaxies, these blobs may have been normal in the distant past, many billions of years ago. This adds evidence that galaxies formed from the conglomeration of smaller objects instead of the fragmentation of larger objects."

[netmassimo]

An article published in the journal "Nature" reports the results of a study on the so-called intracluster light that permeates galaxy clusters. Hyungjin Joo and M. James Jee of Yonsei University in Seoul, South Korea, used the Hubble Space Telescope to examine ten galaxy clusters and the glow within them. The surprising and therefore interesting discovery was that intracluster light is abundant even in the oldest clusters, a sign that the stars that emit it were ejected from their galaxies a long time ago. This suggests that this happened at the same time as the formation and growth of the clusters.

[quiltofstars]

The Hydra Cluster, Abell 1060 // Chris DeCosta

[merelygifted]

James Webb telescope produces an unparalleled view of the ghostly light in galaxy clusters

In clusters of galaxies there is a fraction of stars which wander off into intergalactic space because they are pulled out by huge tidal forces generated between the galaxies in the cluster. The light emitted by these stars is called the intracluster light (ICL) and is extremely faint. Its brightness is less than 1% of the brightness of the darkest sky we can observe from Earth. This is one reason why images taken from space are very valuable for analyzing it.

Infrared wavelengths allow us to explore clusters of galaxies in a different way than with visible light. Thanks to its efficiency at infrared wavelengths and the sharpness of the images of the JWST, IAC researchers Mireia Montes and Ignacio Trujillo have been able to explore the intracluster light from SMACS-J0723.3-7327 with an unprecedented level of detail. In fact the images from the JWST of the center of this cluster are twice as deep as the previous images obtained by the Hubble Space Telescope.

"In this study we show the great potential of JWST for observing an object which is so faint," explains Mireia Montes, the first author of the article. "This will let us study galaxy clusters which are much further away, and in much greater detail," she adds.

In order to analyze this extremely faint "ghostly" light, as well as needing the observational capability of the new space telescoope, the researchers have developed new analysis techniques, which improve on existing methods. "In this work we needed to do some extra processing to the JWST images to be able to study the intracluster light, as it is a faint and extended structure. That was key to avoid biases in our measurements," says Mireia. ...