Tag Archives: cluster

Webb Telescope Explores a Lenticular Galaxy Cluster in the Leo Constellation

Posted on by
Reply

Webb astronomers have unveiled a breathtaking image captured by the NASA/ESA/CSA James Webb Space Telescope, showcasing MACS J1149.5+2223 (MACS J1149), a cosmic collection of hundreds of galaxies situated about 5 billion light-years from Earth in the constellation Leo. The latest images not only highlight the cluster’s brilliant galaxies but also illustrate how their immense gravitational forces uniquely affect the fabric of space-time.

The stunning image of the galaxy cluster MACS J1149.5+2223. Image credits: NASA / ESA / CSA / Webb / C. Willott, National Research Council Canada / R. Tripodi, INAF-Astronomical Observatory of Rome.

The latest Webb image of MACS J1149 dramatically showcases light from background galaxies, which is bent and magnified in a remarkable phenomenon known as gravitational lensing. This creates elongated arcs and distorted shapes, revealing the mass of both clusters.

“The immense gravity of this galaxy cluster does more than hold the galaxies adrift in the universe,” the Webb astronomers explained in a statement.

“As light from galaxies beyond the cluster travels toward our telescope over billions of years, its trajectory through space-time is warped by the gravitational forces of the intervening galaxies.”

This gravitational lensing effect is evident throughout the image of MACS J1149, with galaxies appearing stretched into narrow streaks and others morphing into unusual shapes. A prime example of gravitational lensing can be seen near the image’s center, just below the prominent white galaxy.

In this area, a galaxy with spiral arms has been transformed into a shape resembling a pink jellyfish. This peculiar galaxy once harbored the farthest single star ever identified and a supernova that appeared four times simultaneously.

This remarkable image of MACS J1149 is part of the Canadian NIRISS Unbiased Cluster Survey (CANUCS) program.

“This program employs Webb’s advanced instruments to explore the evolution of low-mass galaxies in the early Universe, shedding light on their star formation, dust content, and chemical makeup,” the astronomers stated.

The data collected will also assist researchers in studying the epoch of reionization, when the first stars and galaxies illuminated the universe, mapping mass distributions in galaxy clusters, and understanding how star formation diminishes within cluster environments.

Source: www.sci.news

Astronomers Unveil Merging Mystery: Champagne Galaxy Cluster is Two Colliding Clusters

Posted on by
Reply

Astronomers unveiled a remarkable giant galaxy cluster known as RM J130558.9+263048.4 on December 31, 2020. Due to its bubble-like appearance and superheated gas, they aptly named it the Champagne Cluster. The stunning new composite image of this galaxy cluster features X-ray data from NASA’s Chandra X-ray Observatory combined with optical information from the Legacy Survey.

The Champagne Cluster appears as a luminous array of galaxies amidst a vibrant neon purple cloud. The cluster reveals over 100 galaxies split into two groups, with notable variations among them. Foreground stars display diffraction spikes surrounded by a subtle haze. Many small galaxies showcase blue, orange, or red tones and exhibit varied shapes. This indicates a multifaceted nature, while the central purple gas cloud emitted by Chandra signals a high-temperature region, indicative of two colliding clusters. Image credit: NASA / CXC / UCDavis / Bouhrik others. / Legacy Survey / DECaLS / BASS / MzLS / SAO / P. Edmonds / L. Frattare.

Recent research led by astronomer Faik Bourik from the University of California, Davis, utilized instruments from NASA’s Chandra X-ray Observatory and ESA’s XMM Newton Observatory to investigate the Champagne Cluster.

The team also analyzed data from the DEIMOS multi-object spectrometer located at the W. M. Keck Observatory.

“Our new composite image indicates that the Champagne Galaxy Cluster consists of two galaxy clusters merging to form a larger cluster,” the astronomers stated.

“In typical observations, multimillion-degree gas is roughly circular, but in the Champagne Cluster, it spans from top to bottom, highlighting the collision of two clusters.”

“Distinct clusters of individual galaxies are prominently visible above and below the center,” they added.

“Remarkably, the mass of this hot gas exceeds that of all 100 or more individual galaxies within the newly formed cluster.”

“This cluster is also abundant in invisible dark matter, a mysterious substance that pervades the universe.”

The Champagne Cluster is part of a rare category of merging galaxy clusters, akin to the well-known Bullet Cluster, where the hot gas from each cluster collides, slows, and creates a clear separation from the heaviest galaxies.

By comparing this data with computer simulations, researchers propose two potential histories for the Champagne Cluster.

One theory suggests that the two star clusters collided over 2 billion years ago, followed by an outward movement due to gravity, leading them to a subsequent collision.

Alternatively, another link posits a single collision about 400 million years ago, after which the clusters have begun moving apart.

“Further studies on the Champagne Cluster could illuminate how dark matter reacts during high-velocity collisions,” the scientists concluded.

For more insights, refer to their published paper in July 2025, featured in the Astrophysical Journal.

_____

Faik Bourik others. 2025. New dissociated galaxy cluster merger: discovery and multiwavelength analysis of the Champagne Cluster. APJ 988, 166;doi: 10.3847/1538-4357/ade67c

Source: www.sci.news

Astronomers Reveal Pleiades Star Cluster is Integral to a Vast Stellar Structure

Posted on by
Reply

The Pleiades star cluster, also referred to as the Seven Sisters and Messier 45, is an open star cluster situated around 440 light-years away from Earth in the Taurus constellation. It forms the central core of a larger network that includes several known star clusters scattered over 600 parsecs (1,950 light-years). This network is known as the Greater Pleiades Complex and comprises at least 3,091 stars.

Pleiades star cluster. Image credit: NASA / ESA / AURA / California Institute of Technology / Palomar Observatory.

Stars originate from clouds of dust and gas. Clumps of this material come together and eventually collapse under their gravity, creating the hot core that becomes a star.

Star formation typically occurs in bursts, with numerous stars being born in rapid succession.

A collection of stars that form from the same molecular cloud is known as a star cluster.

These stars remain gravitationally bound to one another for thousands of years.

Over tens to hundreds of millions of years, the materials that birthed them are expelled by cosmic winds, radiation, and various astrophysical phenomena.

As this occurs, individual stars can merge into their host galaxies, making it complex to ascertain their relationships and trace their origins, especially after more than 100 million years have elapsed.

In a recent study, Dr. Luke Buuma from the Carnegie Institution for Science Observatory and his colleagues concentrated on the Pleiades star cluster.

Utilizing data from NASA’s TESS mission, ESA’s Gaia spacecraft, and the Sloan Digital Sky Survey (SDSS), they discovered that this cluster is the core of a broader structure of related stars spanning over 1,950 light-years.

“We refer to this as the Greater Pleiades Complex,” Dr. Bouma stated.

“It includes at least three known groups of stars, and likely two additional ones.”

“We confirmed that most members of this structure have origins in the same gigantic stellar nursery.”

A key aspect of their methodology is that a star’s rotation rate decreases with age.

The study utilized a combination of TESS’s stellar rotation data (made to detect exoplanets) and Gaia’s stellar motion observations (designed for mapping the Milky Way).

With this information, they developed a new method based on rotation to identify stars that share common origins.

“For the first time, by amalgamating data from Gaia, TESS, and SDSS, we confidently identified a new member of the Pleiades cluster,” reported Dr. Buma.

“Data from each mission alone was not enough to reveal the full scope of the structure.”

“However, when we integrated stellar motions from Gaia, rotations from TESS, and chemical data from SDSS, a coherent picture took shape.”

“It’s akin to piecing together a jigsaw puzzle, where every dataset provides a different piece of a larger whole.”

Besides their comparable ages, the authors highlighted that the stars in the Greater Pleiades cluster share similar chemical compositions and were once much closer to one another.

The fifth generation of SDSS data was employed for the chemical abundance analysis.

“The Pleiades star cluster has been pivotal in human observations of stars since ancient times,” Dr. Buma remarked.

“This research marks a significant advancement in understanding the changes in the Pleiades star cluster since its formation 100 million years ago.”

The researchers believe their findings carry broad implications.

The Pleiades is not merely an astrophysical benchmark for young stars and exoplanets but also a significant cultural symbol, referenced in the Old Testament and Talmud, celebrated as Matariki in New Zealand, and represented on the Subaru logo in Japan.

Professor Andrew Mann of the University of North Carolina at Chapel Hill stated, “We are starting to understand that many stars near the Sun belong to extensive star clusters with intricate structures.”

“Our study provides a novel method to uncover these hidden connections.”

A paper detailing the survey results has been published this week in the Astrophysical Journal.

_____

Andrew W. Boyle et al. 2025. Missing Sister Found: TESS and Gaia Reveal Dissolving Pleiades Complex. APJ 994, 24; doi: 10.3847/1538-4357/ae0724

Source: www.sci.news

A Remarkably Tight Cluster of Protostars Likely Discovered

Posted on by
Reply

Artist’s rendition of a Population III star that existed 100 million years after the Big Bang

Noir Lab/NSF/AURA/J. da Silva/Space Engine/M. Zamani

We may have finally observed the first generation of stars. After decades of searching for these pristine giants, known as Population III stars, astronomers have found their most promising candidate yet.

Population III stars are anticipated to be markedly distinct from today’s stars, or Population I stars. They are believed to have formed from pure hydrogen and helium gases before supernovae and powerful stellar winds dispersed heavier elements across the universe. These stars are also predicted to be larger and hotter than modern counterparts.

That’s precisely the case, according to Eli Visbal. Researchers from the University of Toledo in Ohio made this discovery through a detailed examination of prior James Webb Space Telescope (JWST) observations of a distant galaxy known as LAP1-B. With a redshift of 6.6, this galaxy is visible approximately 800 million years after the Big Bang. Its discovery was facilitated by the magnification of its light due to gravitational lensing by nearby galaxy clusters.

“There’s likely much more to discover in the universe, but we can only see it illuminated by this expanding star cluster,” Visbal noted. When his team estimated how many Population III clusters could exist at this redshift, they figured there should be only one—exactly what they observed. “Our abundance calculations aligned perfectly with those of the previous research team,” he added.

Another advantage of LAP1-B is that it contains only enough stars to comprise several thousand times the mass of the Sun. In contrast, other Population III galaxy candidates usually have significantly larger stellar masses, which do not align with simulations of Population III cluster formation. “This is the most robust candidate we’ve encountered,” says Visbal.

Most Population III stars are thought to have existed and perished between about 100 million and 400 million years after the Big Bang, at which point there were enough heavy elements in the universe to create stars similar to those we observe today. “This object meets many criteria, but I remain somewhat skeptical because these stars emerge later in the timeline, and there may be other viable explanations,” remarks Ralph Cressen from the University of Heidelberg, Germany. “Discovering Population III clusters would be fascinating, but statistically, this would surely be an anomaly.”

However, primordial pockets of hydrogen and helium could linger longer, potentially leading to the formation of Population III stars, as Visbal suggested.

“LAP-B1 is a particularly intriguing candidate, but we are still far from the clear and undeniable indications we would need for definite identification of Population III,” comments Roberto Maiorino at Cambridge University. “[For these to truly be Population III stars] it requires an extremely fortunate combination of factors, each of which is quite rare on its own, and even rarer when they occur together. Further observations and in-depth simulations are essential to ascertain whether LAP1-B represents the first detection of these enigmatic stars.

Understanding Population III stars is crucial, as they offer insights into the formation of the universe’s first heavy elements. “They reveal how the universe’s chemistry evolved from being solely hydrogen and helium to the diverse range of chemicals, life, and entities that exist today,” Visbal states. The stars of Population III were the pioneering building blocks of the complexity encompassing us now.

Topics:

Source: www.newscientist.com

Decam Reveals Hidden Cluster Light in Galaxy Cluster Abell 3667

Posted on by
Reply

The glow within the cluster is the soft luminosity of stars that have been stripped from their galaxy amidst the layers of galaxy clusters.

Abell 3667 is depicted in this Decam image. Image credits: CTIO/NOIRLAB/NSF/AURA/ANTHONY ENGLERT, Brown University/TA Rector, Noirlab/M. Zamani & D of University of Alaska Anchorage & NSF. De Martin, NSF’s Noirlab.

Galaxy clusters comprise thousands of galaxies, varying widely in age, shape, and size.

Typically, they have a mass about 10 billion times that of the Sun.

Historically, galactic clusters were regarded as the largest structures in the universe, spanning hundreds of millions of light-years and including numerous galactic clusters and groups, until superclusters were discovered in the 1980s.

Nonetheless, galaxy clusters still hold the title of the largest gravitationally bound structure in the universe.

“The study of galaxy clusters not only informs us about the formation of the universe, but it also places constraints on the characteristics of dark matter,” stated Brown University astronomer Anthony Englat and his team.

One significant clue astronomers seek to grasp the history of galactic clusters is the light within the cluster. This faint glow is emitted by stars that have been stripped from their original galaxy due to the immense gravitational forces of the forming galaxy cluster.

These stars provide evidence of past galactic interactions, although most current telescopes and cameras face challenges in detecting them.

The subtle intra-cluster light from the galaxy cluster Abel 3667 shines vividly in new images created from a total of 28 hours of observation at 570 megapixels using the Dark Energy Camera (Decam) at NSF’s M. Blanco 4-M Telescope, a program of NSF’s Noirlab at Cerro Tololo Inter-American Observatory.

“Abell 3667 is located over 700 million light-years away from us,” the astronomer mentioned.

“Most of the faint light sources in this image are distant galaxies, not foreground stars from our own Milky Way.”

“In Abell 3667, two small galaxy clusters are currently merging, as evidenced by the luminous bridge (yellow) of stars extending toward the center of this image.”

“This bridge is formed from material stripped off from the merging galaxies, forming one massive conglomerate known as the brightest cluster galaxy.”

“Not only does this sparkling sky encompass distant galaxies, but it also highlights faint foreground features due to the prolonged exposure.”

“The Milky Way’s hair follicles, or integrated flux nebula, consist of faint clouds of interstellar dust that appear as soft bluish chains crossing the image.”

“These structures are patches of dust that are illuminated by the light of the stars within our own galaxy.”

“They present as diffuse, filamentous formations that can span extensive areas of the sky.”

Survey results will be published in the Astrophysics Journal Letter.

____

Anthony M. Engrat et al. 2025. Announcing optical bridges in Abel 3667 in-cluster light: LSST precursor data. apjl 989, L2; doi: 10.3847/2041-8213/ade8f1

Source: www.sci.news

Webb Examines the Behemoth Galaxy Cluster: Abell S1063

Posted on by
Reply

Astronomers utilizing the NASA/ESA/CSA James Webb Space Telescope have captured incredible new images of the Galaxy Cluster Abell S1063.

This Webb image illustrates the colossal galaxy cluster Abell S1063. Image credits: NASA/ESA/CSA/Webb/H. Atek & M. Zamani, ESA & Webb/R. Endley.

Abell S1063 is a significant cluster of galaxies located about 4.5 billion light years away in the constellation Grus.

This cluster houses approximately 100 million solar masses, including 51 confirmed galaxies, with potentially over 400 more yet to be identified.

The enormous mass of Abell S1063 bends and magnifies light from galaxies located behind it, an effect known as gravitational lensing.

“Upon closer examination, this dense grouping of massive galaxies is encircled by glowing light streaks, and these warped arcs are the essence of our interest: faint galaxies from the distant past of the universe.”

“Abell S1063 was previously explored by the Frontier Fields program using the NASA/ESA Hubble Space Telescope.”

“It possesses a remarkable gravitational lens. The immense size of these galaxy clusters causes light from the distant galaxies positioned behind them to curve around them, forming the distorted arcs visible here.”

“Similar to a glass lens, it directs light from these remote galaxies.”

“The resulting image, while distorted, is bright and magnified, making it possible for observation and study.”

“This was Hubble’s objective — to investigate the early universe using galaxy clusters as a magnifying glass.”

A new image of Abell S1063 was captured by Webb’s Near-Infrared Camera (NIRCam).

“The image reveals an astonishing array of structures around Abell S1063, showcasing distorted background galaxies at various distances, along with numerous faint galaxies and previously unseen features,” the researchers noted.

“This image is classified as a deep field. It focuses on a single segment of the sky for an extended period, gathering as much light as possible to detect the faintest distant galaxies that aren’t visible in standard images.”

“It comprises nine distinct snapshots of different near-infrared wavelengths, totaling approximately 120 hours of observation time, enhanced by the gravitational lensing effect. This marks Webb’s deepest observation of a single target to date.”

“Thus, directing such observational capability at a large gravitational lens, like Abell S1063, could uncover some of the earliest galaxies formed in the early universe.”

Source: www.sci.news

Hubble’s Close-Up of the Spherical Cluster Messier 72

Posted on by
Reply

As part of Hubble’s 35th anniversary ceremony, astronomers have acquired a stunning new image of a rich collection of scattered stars. Messier 72.

This Hubble image shows the Messier 72, a spherical cluster about 50,000 light years away in the constellation of Aquarius. Image credits: NASA/ESA/Hubble/A. Sarajedini / G. Piotto / M. libralato.

Spherical clusters are a very old star system, coupled to a single structure, about 100-200 light-years by gravity.

They contain hundreds of thousands, or perhaps million stars. Large masses at the center of the rich stars in the cluster pull the stars inward to form a ball of stars.

Spherical clusters are one of the oldest known objects in the universe and are relics from the first era of the Galactic Layer.

It is believed that all galaxies have a population of spherical clusters. Our Milkyway Galaxy hosts at least 150 such objects, and could be hidden behind the thick disks of the Galaxy.

Messier 72 is It was located It is about 50,000 light years away from Earth, the constellation of Aquarius.

This spherical cluster, also known as the M72 or NGC 6981, is almost 9.5 billion years old.

Its apparent size is 9.4, and appears as a faint patch of light on a small telescope. The best time to observe it is September.

Messier 72 was the first one I discovered it In 1780, by Pierre Messine, a French astronomer and colleague of Charles Messier.

It is the first of the five-star clusters Mechine discovers while assisting Messier, and one of the most remote clusters in Messier’s catalog.

“Messier 72 is a particularly special target as it was the first image to be released in the Hubble Picture of the Week series on April 22, 2010,” Hubble Astronomers said in a statement.

“For 15 years, our team has been publishing new Hubble images every Monday for everyone to enjoy.”

“This has added nearly 800 images to the vast Hubble Image Archive over the years.”

“The impressive variety of star colours in the new Messier 72 images, especially compared to the original image, is the result of adding UV observations to previous visible light data,” they added.

“Colors indicate different types of stars.”

“The blue star is a cluster star originally larger, and after burning much of its hydrogen fuel, it now reaches a hotter temperature. The bright red object is a low-mass star that is now a red giant.”

“Studying these different groups will help you understand the spherical clusters and how the galaxies in which they were born were first formed.”

Source: www.sci.news

DECam captures close-up of the Antria galaxy cluster

Posted on by
Reply

The Antria Galaxy Cluster is a group of at least 230 galaxies brought together by gravity. This galaxy cluster is rare. Unlike most other galaxy clusters, there appears to be no dominant galaxy within it.

The Antria star cluster is dominated by two giant elliptical galaxies: NGC 3268 (center) and NGC 3258 (bottom right). Image credits: Dark Energy Survey / DOE / FNAL / DECam / CTIO / NOIRLab / NSF / AURA / R. Colombari & M. Zamani, NSF's NOIRLab.

Galaxy clusters, like stars and galaxies, are fundamental building blocks of the universe.

These structures typically contain thousands of galaxies of all ages, shapes, and sizes.

They have a mass about a million times the mass of the Sun and are formed over billions of years as groups of small galaxies slowly come together.

At one point, galaxy clusters were believed to be the largest structures in the universe, until they were supplanted by the discovery of superclusters in the 1980s. Its length spans hundreds of millions of light years.

However, there is one thing the cluster holds on to. Because superclusters are not held together by gravity, galaxy clusters still hold the title of the largest gravitationally bound structures in the universe.

“Galaxy clusters are some of the largest known structures in the known universe,” NOIRLab astronomers said in a statement.

“Current models suggest that these giant structures form as clumps of dark matter, and that the galaxies that form within them are pulled together by gravity to form groups of dozens of galaxies, which then merge to form groups of several dozen galaxies. This suggests that they form clusters of hundreds or even thousands of galaxies.

“One such group is antoria clusterlocated approximately 130 million light-years from Earth in the direction of the constellation Antolia. ”

The Antlia cluster, also known as Abell S636, 3rd closest Add it to the local group after the Virgo and Fornax clusters.

The new images of the Antolia star cluster were captured by the Dark Energy Camera (DECam) mounted on NSF's Victor M. Blanco 4-meter telescope at Cerro Tololo Inter-American Observatory in Chile, a program of NSF's NOIRLab.

It captures only a portion of the 230 galaxies so far discovered to make up this cluster, as well as thousands of background galaxies.

“Antria Cluster” host Two giant elliptical galaxies: NGC3268 and NGC 3258,” the astronomers said.

“These central galaxies are surrounded by numerous faint dwarf galaxies.”

“Based on X-ray observations that revealed the existence of a 'rope' of globular clusters along the optical peak region between these two galaxies, we believe that these two galaxies are in the process of merging. Masu.”

“This may be evidence that the Antlia cluster is actually two smaller clusters joined together.”

“The cluster is rich in lenticular galaxies (a type of disk galaxy with little interstellar medium and therefore little continuous star formation), as well as some irregular galaxies,” the researchers added. .

“Many rarer, lower-luminosity dwarf galaxies have been discovered within this cluster, including ultracompact dwarfs, compact elliptical galaxies, and blue compact dwarfs.”

“The Antria cluster may also contain subtypes of dwarf spheroidal and superdiffuse galaxies, but further investigation is needed to confirm these.”

“Many of these galaxy types have been identified within the past few decades, as advances in observational instruments and data analysis techniques have allowed us to better capture the low luminosity and relatively small size of these galaxies. It just happened.”

“Assessing galaxy types allows us to plot details of their evolution, and some galaxies are rich in dark matter, providing further opportunities to understand this mysterious material, which makes up 25% of the universe. We will provide it.”

Source: www.sci.news

Interacting Pairs of Galaxies in the Kaminoke Galaxy Cluster Spotted by Hubble

Posted on by
Reply

This amazing new image from the NASA/ESA Hubble Space Telescope is one of the best ever of a galaxy combination called MCG+05-31-045.

This Hubble image shows MCG+05-31-045, a pair of interacting galaxies located approximately 390 million light-years apart in the constellation Coma. Image credit: NASA/ESA/Hubble/RJ Foley, University of California, Santa Cruz.

MCG+05-31-045 It is located approximately 390 million light-years away in the constellation of Coma.

This galaxy pair, also known as IC 3935, AGC 221216, or LEDA 44438, is part of the Coma cluster.

“The Coma cluster is a particularly rich galaxy cluster, containing more than 1,000 known galaxies,” Hubble astronomers said in a statement.

“Some are easily visible with amateur telescopes.”

“Most of them are elliptical galaxies, which are typical of dense galaxy clusters like the Milky Way Cluster. Many elliptical galaxies are created when galaxies come close to each other and collide, stirring them up or They are formed when groups are torn apart.

“Stars in interacting galaxies can stay together, but gas in galaxies is a different story. Gas is twisted and compressed by gravity and is quickly used up to form new stars.” Masu.”

“When hot, massive blue stars die, there is little gas left to replace them with a new generation of young stars.”

“In the case of interacting spiral galaxies, the regular orbits that give rise to their impressive spiral arms are also disrupted.”

“Whether it’s a merger or a simple near-miss, the result is a galaxy with little gas and aging stars orbiting in uncoordinated circles – elliptical galaxies.”

“A similar fate is very likely to befall MCG+05-31-045,” the astronomers said.

“When small spiral galaxies are torn apart and merged into larger galaxies, many new stars are formed, and the hot, blue stars quickly burn out, leaving colder, redder stars like other stars in a coma. is left behind in the elliptical galaxy.” “

“But this process will take millions of years to complete. Until then, Queen Berenice II will suffer from knots in her hair.”

Source: www.sci.news

IC 3225 in Virgo Cluster shows signs of being stripped of Ram pressure by Hubble

Posted on by
Reply

Early galaxies are dominated by bright galaxy clusters, which are larger and more massive than the local Universe. Star formation activity can be strongly influenced and even halted by many processes that are directly related to the environment in which galaxies exist. Ram pressure stripping, the removal of interstellar gas from the disk of star-forming galaxies by hydrodynamic interaction with the hot intergalactic medium, is one such process that It is thought to have a strong influence on the galaxy population. Groups, especially clusters.

This Hubble image shows spiral galaxy IC 3225 with Ram pressure removed. Image credit: NASA / ESA / Hubble / M. Sun.

IC 3225 is a spiral galaxy located approximately 100 million light years away in the constellation Virgo.

Also known as LEDA 40111 or UGC 7441, discovered It was announced on November 4, 1899 by German astronomer Arnold Schwassmann.

“IC 3225 looks strikingly like it was fired from a cannon, hurtling through space like a comet with a tail of gas streaming from the disk behind it,” Hubble astronomers said in a statement.

“IC 3225 is one of more than 1,300 members of the Virgo cluster, so the galaxy's location suggests several causes for this active scene.”

“While the density of galaxies within the Virgo cluster creates a rich field of hot gas between them, the so-called intracluster medium, the extreme mass of this cluster also allows for some extremely There are galaxies that orbit around the center in fast orbits.”

“Collision into thick intracluster material, especially near the center of a galaxy cluster, places enormous collision pressures on the moving galaxy, stripping the gas from the moving galaxy.”

“Although IC 3225 is currently not very close to the center of the cluster, astronomers suspect that it has undergone such ram pressure removal in the past,” the researchers noted.

“This galaxy looks as if it has been affected by this. One side of the galaxy is compressed and there is significantly more star formation at this leading edge, while the other end is misshapen. Masu.”

“Being in such a crowded region, a close call with another galaxy may have pulled IC 3225 and created this shape.”

“The sight of this distorted galaxy is a reminder of the incredible forces at work on an astronomical scale that move and reshape entire galaxies.”

This new image of IC 3225 consists of observations from. Hubble's advanced survey camera (ACS) in the near-infrared and optical portions of the spectrum.

Two filters were used to sample different wavelengths. Color is obtained by assigning different hues to each monochromatic image associated with an individual filter.

Source: www.sci.news

VST finds jellyfish galaxy in the Hydra cluster

Posted on by
Reply

Astronomers ESO’s Very Low Tilt Survey Telescope The Chilean VST satellite has captured a stunning image of the distorted spiral galaxy NGC 3312.

This VST image shows the spiral galaxy NGC 3312. Image courtesy of ESO / INAF / M. Spavone / E. Iodice.

NGC 3312 It is located in the constellation Hydra and is more than 160 million light years away from Earth.

Also known as ESO 501-43, IC 629, IRAS 10346-2718, LEDA 31513, Found It was discovered on March 26, 1835 by British astronomer John Herschel.

NGC 3312 is Hydra I Cluster (Abell 1060) is a galaxy cluster containing over 150 luminous galaxies.

As galaxies move through the hotter gas in the cluster, they lose cooler gas.

It is likely distorted by the cluster’s main elliptical galaxies, NGC 3309 and NGC 3311.

“The spiral galaxy in the centre of this VST image appears fuzzy across the entire screen, seemingly leaking its contents into the surrounding space,” ESO astronomers said in a statement.

“This is NGC 3312, the victim of an astrophysical robbery: ram-pressure stripping.”

“This occurs when galaxies move through a dense fluid, such as the hot gas suspended between galaxies in a cluster,” the researchers explained.

“This hot gas is pulled by the cooler gas in the outer shell of the galaxy, causing it to be pulled out of the galaxy and leak out into space.”

“This cold gas is the raw material for star formation, which means that galaxies that are losing gas in this way are at risk of losing a decrease in their stellar population.”

“Affected galaxies, typically those that fall into the center of a cluster, tend to eventually form long trailing tendrils of gas behind them, which is where their nickname ‘jellyfish galaxies’ comes from.”

“This is just one of the many astronomical processes that make our cosmic pictures so diverse and fascinating.”

Source: www.sci.news

Astronomers find intermediate-mass black hole in largest globular cluster in Milky Way

Posted on by
Reply

Using more than 500 images from the NASA/ESA Hubble Space Telescope, astronomers have found evidence of a 20,000-solar-mass black hole at the center of Earth. Omega CentauriIt is a globular cluster located in the constellation Centaurus, 5,430 parsecs (17,710 light years) from the Sun.

Omega Centauri is about 10 times more massive than other large globular clusters. Image credit: NASA / ESA / Hubble / Maximilian Häberle, MPIA.

Astronomers know that stellar-mass black holes (black holes with masses between 10 and 100 times that of the Sun) are the remnants of dying stars, and that supermassive black holes, with masses more than a million times that of the Sun, exist at the center of most galaxies.

But the universe is littered with what appear to be more mysterious types of black holes.

These intermediate-mass black holes, with masses between 100 and 10,000 times that of the Sun, are so difficult to measure that their very existence is sometimes debated.

Only a few intermediate-mass black hole candidates have been discovered so far.

Determining the black hole population is an important step towards understanding the formation of supermassive black holes in the early universe.

“Omega Centauri is a special example among globular clusters in the Milky Way,” said astronomer Maximilian Höberle of the Max Planck Institute for Astronomy and his colleagues.

“Omega Centauri is widely accepted to be the stripped core of an accreted dwarf galaxy due to its high mass, complex stellar population and kinematics.”

“These factors, combined with its proximity, make the planet a prime target in the search for intermediate-mass black holes.”

Omega Centauri is made up of about 10 million stars, making it about 10 times more massive than any other large globular cluster.

In the study, the authors measured the velocities of 1.4 million stars from images of the cluster taken by the Hubble Space Telescope.

Although most of these observations were intended for calibration of Hubble's instruments rather than for scientific use, they proved to be an ideal database for the team's research activities.

“We looked for fast-moving stars that are expected to be near concentrated masses such as black holes,” said astronomer Holger Baumgart of the University of Queensland.

“Identifying these stars was the smoking gun we needed to prove the existence of black holes, and we've done just that.”

“We found seven stars that shouldn't be there,” Dr Hebel said.

“They're moving so fast that they're likely to escape the herd and never come back.”

“The most likely explanation is that a very massive object is gravitationally tugging on these stars, keeping them near the center.”

“The only objects this massive are black holes, which have a mass at least 8,200 times that of the Sun.”

“This discovery is the most direct evidence to date for the presence of an intermediate-mass black hole at Omega Centauri,” said Dr Nadine Neumayer, an astronomer at the Max Planck Institute for Astronomy.

“This is extremely exciting because very few other black holes with similar masses are known.”

“The black hole at Omega Centauri may be the best example of an intermediate-mass black hole in our cosmic neighborhood.”

Team paper Published in the journal Nature.

_____

M. Heberle others2024. Stars moving at high speed around the intermediate-mass black hole at Omega Centauri. Nature 631, 285-288; Source: 10.1038/s41586-024-07511-z

Source: www.sci.news

Webb finds early universe protoglobular cluster

Posted on by
Reply

Astronomers using the NASA/ESA/CSA James Webb Space Telescope have discovered at least five young globular clusters within SPT 0615-JD1 (also known as the Cosmic Gems Arc), a strongly lensed galaxy that existed when the universe was 460 million years old.

These images show the galaxy cluster SPT-CL J0615-5746 (right) and part of this cluster (left), showing two clearly lensed galaxies. The Cosmic Gems arc is shown along with several galaxy clusters. Images courtesy of NASA / ESA / CSA / Webb / L. Bradley, STScI / A. Adamo, Stockholm University / Cosmic Spring Collaboration.

“These galaxies are thought to be the main source of intense radiation that reionized the early universe,” said Dr Angela Adamo, astronomer at Stockholm University and the Oskar Klein Centre.

“What’s special about the Cosmic Gems Ark is that thanks to gravitational lensing, we can actually resolve galaxies down to the parsec scale.”

SPT 0615-JD1 was originally discovered in Hubble Space Telescope images obtained by the RELICS (Reionizing Lensing Cluster Survey) program of the lensing galaxy cluster SPT-CL J0615-5746, located about 7.7 billion light-years away in the constellation of Scorpio.

The Webb telescope will enable Dr Adamo and his colleagues to see where stars are forming and how they are distributed, in a similar way that the Hubble telescope is used to study the local galaxy.

Webb’s observations provide a unique opportunity to study star formation and the internal structure of young galaxies at unprecedented distances.

“The combination of the Webb Telescope’s incredible sensitivity and angular resolution at near-infrared wavelengths, along with gravitational lensing by a large foreground galaxy cluster, made this discovery possible that would not have been possible with any other telescope,” said Dr. Larry Bradley, an astronomer at the Space Telescope Science Institute.

“The surprise and excitement I felt when I first opened the Webb images was overwhelming,” Dr. Adamo said.

“We saw a string of tiny bright dots projected from one side to the other. These cosmic gems are star clusters.”

“Without Webb, we would never have known we were observing star clusters in such a young galaxy.”

Astronomers say the discovery connects different scientific disciplines.

“These results provide direct evidence of the formation of protoglobular clusters in faint galaxies during periods of reionization and help us understand how these galaxies successfully reionized the Universe,” Dr Adamo said.

“This discovery also places important constraints on the formation of globular clusters and their early properties.”

“For example, the high stellar densities found in galaxy clusters provide the first indications of processes occurring within them and give new insights into the possible formation of very massive stars and black hole seeds that are important for the evolution of galaxies.”

In the future, the team hopes to construct a sample of galaxies that can achieve a similar resolution.

“I am convinced that there are more such systems in the early universe waiting to be discovered, which will improve our understanding of early galaxies even further,” said Dr Eros Vanzella, astronomer at the Bologna Observatory for Astrophysics and Space Sciences (INAF).

of Investigation result Published in today’s journal Nature.

_____

A. Adamo othersA bound star cluster observed in a lensed galaxy 460 million years after the Big Bang. NaturePublished online June 24, 2024, doi: 10.1038/s41586-024-07703-7

Source: www.sci.news

‘Hubble Space Telescope Discovers Intricate Galaxy in Virgo Galaxy Cluster’

Posted on by
Reply

The Hubble team has released a beautiful new image of the dwarf galaxy IC 776 in the constellation Virgo.

This Hubble image shows IC 776, a dwarf galaxy about 100 million light-years away in the constellation Virgo. Image credit: NASA / ESA / Hubble / M. Sun.

IC776 It is located in the constellation Virgo, about 100 million light years away from Earth.

This galaxy, also known as ALFALFA 3-210, LEDA 39613, and UGC 7352, discovered It was announced by French astronomer Stéphane Javert on May 4, 1893.

IC 776 is Virgo Clusterthe nearest and best-studied large galaxy cluster.

It is a dwarf galaxy and is also classified as a dwarf galaxy. SAB type One study calls this the “complex case” in morphology.

“This extremely detailed observation from Hubble illustrates its complexity,” Hubble astronomers said in a statement.

“IC 776 has a ragged and disorganized disk, but it still appears to spiral around a central core, creating an arc of star-forming regions.”

The color image of IC 776 was created from separate exposures taken in the visible and near-infrared regions of the spectrum. Hubble's advanced survey camera (ACS).

Two filters were used to sample different wavelengths. Color is obtained by assigning different hues to each monochromatic image associated with an individual filter.

“This image comes from an observational program dedicated to the study of dwarf galaxies in the Virgo cluster and searching for X-ray sources in such galaxies,” the researchers said.

“X-rays are often emitted from accretion disks, where matter pulled into a compact object by gravity collides, forming a hot, glowing disk.”

“This compact object could be a white dwarf or neutron star that steals material from its companion star, or it could be a supermassive black hole at the center of a galaxy that consumes its surroundings.”

“Dwarf galaxies like IC 776 passing through the Virgo cluster can experience pressure from intergalactic gas, stimulate star formation, and feed the black hole at the galaxy's center,” the study says. they added.

“It could produce a high-energy accretion disk that is hot enough to emit X-rays.”

“Hubble cannot see X-rays, but in conjunction with X-ray telescopes such as NASA's Chandra, it can use visible light to reveal the source of this radiation in high resolution.”

“Dwarf galaxies are thought to be of great importance for understanding cosmology and galaxy evolution.”

“As with many fields of astronomy, the ability to examine these galaxies across the electromagnetic spectrum is critical to research.”

Source: www.sci.news

Hubble Observes Large Globular Cluster in Large Magellanic Cloud

Posted on by
Reply

Astronomers using the NASA/ESA Hubble Space Telescope have captured detailed images of the globular star cluster NGC 1651 in the constellation Mensa.

This Hubble image shows the globular cluster NGC 1651 about 162,000 light-years away in the constellation Mensa. Image credits: NASA / ESA / Hubble / L. Girardi / F. Niederhofer.

Globular clusters are densely packed spherical clusters of hundreds of thousands or even millions of stars.

They are among the oldest known objects in the universe and are preferentially associated with the oldest components of galaxies.

There are at least 150 such objects in our Milky Way, and several more may be hidden behind the galaxy's thick disk.

NGC1651 is part of the Large Magellanic Cloud, the largest and brightest of the Milky Way's satellite galaxies.

beginning discovered Discovered by British astronomer John Herschel on November 3, 1834, this globular cluster is located approximately 162,000 light-years away in the constellation Mensa.

NGC 1651, also known as ESO 55-30 or LW 12, has a diameter of 120 light years.

“A remarkable feature of this image is that NGC 1651 nearly fills the entire image, even though the globular cluster is only about 10 to 300 light-years in diameter,” Hubble astronomers said. Masu.

“In contrast, there are many Hubble images that feature entire galaxies, tens or even hundreds of millions of light-years in diameter, that more or less fill the entire image.”

Color images of NGC 1651 consist of observations from. Hubble's Wide Field Camera 3 Found in the near-infrared and optical portions of the spectrum.

“A common misconception is that Hubble and other large telescopes can observe objects of vastly different sizes by zooming in, much like we would with special cameras on Earth,” the astronomers said. Ta.

“However, while smaller telescopes may have the option to zoom in and out to some extent, larger telescopes do not.”

“Each telescope instrument has a fixed 'field of view' (the size of the area of the sky that can be observed in a single observation).”

“For example, WFC3's ultraviolet/visible light channel, the channel and instrument used to collect the data used in this image, has a field of view that is approximately one-twelfth the diameter of the moon as seen from Earth. Masu.”

“Every time WFC3 makes an observation, it becomes the size of the region of sky it can observe.”

“There are two reasons why Hubble is able to observe objects with such widely different sizes,” the researchers said.

“First, the distance to an object determines how big that object appears from Earth, so an entire galaxy that is relatively far away is compared to a relatively nearby globular cluster like NGC 1651. could take up the same amount of space as the sky.''

“In fact, a distant spiral galaxy lurks just to the left of the cluster in this image. It's undoubtedly much larger than the cluster, but here it appears small enough to blend in with the foreground stars.”

“Second, multiple images across different parts of the sky can be mosaicked to create a single image of an object too large for Hubble's field of view.”

Source: www.sci.news

Astronomers find previously unknown quasar in far-off galaxy cluster

Posted on by
Reply

Astronomers used NASA’s Chandra X-ray Observatory and NSF’s Carl G. Jansky Very Large Array (VLA) to locate H1821+643, the closest quasar hosted by a galaxy cluster, about 3.4 billion light years away. The quasar was found to be more powerful than many supermassive black holes in other galaxy clusters.

This composite image shows quasar H1821+643.Image credit: NASA / CXC / University of Nottingham / Russell other. / NSF / NRAO / VLA / SAO / N. Walk.

Quasars are a rare and extreme class of supermassive black holes that violently pull matter inward, producing intense radiation and sometimes powerful jets.

This quasar, known as H1821+643, is about 3.4 billion light-years from Earth and contains a black hole with a mass of 4 billion solar masses.

Most growing supermassive black holes pull matter in at a slower rate than quasars.

Astronomers have been studying the effects of these more common black holes by observing black holes at the centers of galaxy clusters.

Periodic explosions from such black holes prevent the massive amount of superheated gas embedded in the black hole from cooling down, increasing the number of stars forming in its host galaxy and the fuel pouring toward the black hole. limit the amount of

Little is known about how much influence quasars within galaxy clusters have on their surroundings.

“Our research shows that quasars appear to have given up much of the control imposed by slower-growing black holes. The appetite of black holes is unmatched in their influence,” Nottingham said. University astronomer Dr Helen Russell said.

To reach this conclusion, Russell and his colleagues used Chandra to study the hot gas surrounding H1821+643 and its host galaxy.

But the bright X-rays from quasars have made it difficult to study the weaker X-rays from hot gases.

“To reveal the effects of a black hole, we had to carefully remove the X-ray glare. Then we found that it actually had little effect on its surroundings,” says Harvard University. said Dr. Paul Nalsen, an astronomer at the Smithsonian Center for Astrophysics.

Using Chandra, astronomers discovered that the density of gas near the black hole at the center of a galaxy is much higher than in more distant regions, and the temperature of the gas is much cooler.

Researchers believe that when there is little or no energy input (usually from an explosion from a black hole), hot gas behaves this way to prevent it from cooling and flowing toward the center of the cluster. Expect.

“The supermassive black hole generates far less heat than other black holes at the center of galaxy clusters. This allows the hot gas to cool rapidly and form new stars, which fuel the black hole. It also acts as a source,” said Dr Lucy Crews, an astronomer at the Open University.

The researchers determined that the equivalent of about 3,000 solar masses per year of hot gas has cooled to the point where it is no longer visible in X-rays.

This rapid cooling easily supplies enough material for the 120 solar masses of new stars observed to form each year within the host galaxy and the 40 solar masses consumed by black holes each year. be able to.

The scientists also investigated the possibility that radiation from quasars directly causes cooling of the cluster's hot gases.

This involves photons of light from the quasar colliding with electrons in the hot gas, increasing the energy of the photons and causing the electrons to lose energy and cool down.

This study showed that this type of cooling is probably occurring within the cluster containing H1821+643, but is too weak to explain the large amount of gas cooling seen.

Dr Thomas Braben, an astronomer at the University of Nottingham, said: “This black hole may not be producing enough because it isn't pumping any heat into its surroundings, but the current situation won't last forever.'' ” he said.

“Ultimately, the rapid uptake of fuel by the black hole should increase the jet's power and strongly heat the gas.”

“After that, the growth of the black hole and its galaxy should slow down significantly.”

team's paper will be published in Royal Astronomical Society Monthly Notices.

_____

HR Russell other. 2024. Cooling flow around low-redshift quasar H1821+643. MNRAS, in press. arXiv: 2401.03022

Source: www.sci.news

Hubble Observes NGC 1841 Globular Cluster

Posted on by
Reply

This new image from the NASA/ESA Hubble Space Telescope shows the globular star cluster NGC 1841 in the Large Magellanic Cloud.

This Hubble image shows the globular cluster NGC 1841 about 162,000 light-years away in the constellation Mensa. The color images include ultraviolet, optical, and near-infrared observations from both Hubble's Wide Field Camera 3 (WFC3) and Survey Altitude Camera (ACS). Three filters were used to sample different wavelengths. Color is obtained by assigning different hues to each monochromatic image associated with an individual filter. Image credits: NASA / ESA / Hubble / A. Saragedini / F. Niederhofer.

NGC1841 It is located approximately 162,000 light years away in the constellation Mensa.

The cluster is discovered It was proposed by British astronomer John Herschel on January 19, 1836.

Also known as ESO 4-15, this galaxy is part of the Large Magellanic Cloud, a satellite galaxy of our Milky Way.

“Satellite galaxies are galaxies that are gravitationally bound in orbit around a larger host galaxy,” Hubble astronomers said in a statement.

“While we usually think of our galaxy's closest galactic companion as the Andromeda galaxy, it would be more accurate to say that the Andromeda galaxy is the closest galaxy that does not orbit the Milky Way.”

“In fact, our galaxy is orbited by dozens of known satellite galaxies much closer than Andromeda, the largest and brightest of which is the Large Magellanic Cloud, which is easily visible to the naked eye even from the southern hemisphere. can.”

Globular clusters, such as NGC 1841, are very old systems of stars bound together by gravity into a single structure about 100 to 200 light-years in diameter.

These objects contain hundreds of thousands, or perhaps millions, of stars. The large mass in the cluster's rich stellar center pulls the stars inward, forming a star ball.

These are among the oldest objects known in the universe, relics from the earliest era of galaxy formation.

It is believed that all galaxies contain globular clusters. There are at least 150 such objects in our Milky Way galaxy.

“There are many globular star clusters in the Large Magellanic Cloud,” the astronomers said.

“These objects lie somewhere between open clusters (much less dense and tightly bound) and small, compact galaxies.”

“Increasingly sophisticated observations have revealed that the stellar populations and other characteristics of globular clusters are diverse and complex, but how these dense clusters form is poorly understood. yeah.”

“But all globular clusters have a certain consistency. They are so stable that they can persist for long periods of time, and therefore can be very old.”

“This means that globular clusters often contain large numbers of very old stars, making them similar to 'fossils' in the sky.”

“Just as fossils provide insight into the early development of life on Earth, globular clusters like NGC 1841 provide insight into the very early formation of stars in galaxies.”

Source: www.sci.news

Scientists observe massive outburst from supermassive black hole in far-off galaxy cluster

Posted on by
Reply

Some of the gas erupts from the supermassive black hole located at the center of galaxy cluster SDSS J1531+3414 (abbreviated SDSS J1531) until it reaches a temperature high enough to form numerous star clusters. Cooled down.

Multi-wavelength image of the massive galaxy cluster SDSS J1531+3414.Image credits: NASA / CXC / SAO / Omorui other. / STScI / Tremblay other. / Astron / Loafers / NASA / CXC / SAO / N. Walk.

SDSS J1531 is a huge galaxy cluster containing hundreds of individual galaxies and a huge reservoir of hot gas and dark matter.

At the center of SDSS J1531, two of the cluster's largest galaxies collide with each other.

Surrounding these merging giants are 19 large star clusters called superclusters, arranged in an “S” shape similar to beads on a string.

Dr. Osase Omoruyi and colleagues at Harvard University and the Smithsonian Center for Astrophysics are using NASA's Chandra X-ray Observatory, the LOFAR radio network, and other telescopes to discover how this chain of unusual star clusters formed. I found out what happened.

The discovery of evidence of an ancient mega-eruption in SDSS J1531 provided important clues.

The eruption may have occurred when a supermassive black hole at the center of one of the large galaxies produced a very powerful jet.

As the jet traveled through space, it pulled surrounding hot gas away from the black hole, creating a huge cavity.

“We're already observing this system as it existed 4 billion years ago, when the Earth was just forming,” Omoruyi said.

“This ancient cavity is a fossil of the black hole's influence on its host galaxy and its surroundings, and tells us about important events that occurred almost 200 million years ago in the history of this star cluster.”

Evidence for the cavity comes from bright X-ray emission “wings” seen on Chandra that track dense gas near the center of SDSS J1531.

These wings form the edges of the cavity, and the less dense gas between them is part of the cavity.

LOFAR shows radio waves from the remains of the jet's energetic particles filling a huge cavity.

Taken together, these data provide convincing evidence for an ancient great explosion.

Astronomers also discovered cold and warm gas near the cavity's opening, detected by the Atacama Large Millimeter and Submillimeter Array (ALMA) and Gemini North Telescope, respectively.

They argue that some of the hot gas pushed out of the black hole eventually cooled down to cold, warm gas.

They believe that the tidal effects of the two galaxies merging compressed the gas along a curved path, forming the star cluster in a “string-bead” pattern.

“We reconstructed the sequence of events that may have occurred within this cluster over a wide range of distances and times,” said Dr. Grant Tremblay, also of Harvard University and the Smithsonian Center for Astrophysics.

“It started when a black hole, just one light-year in diameter, formed a cavity about 500,000 light-years wide.”

“This single event triggered the formation of young star clusters almost 200 million years later, each several thousand light-years in diameter.”

Although the authors only looked at the radio waves and cavity from one jet, black holes typically fire two jets in opposite directions.

They also observed radio emissions further out from the galaxy that could be the remains of a second jet, but it was unrelated to the detected cavity.

They speculate that radio and X-ray signals from other eruptions may have diminished to the point where they could no longer be detected.

“We believe the evidence for this large-scale eruption is strong, but further observations from Chandra and LOFAR will confirm the case,” Dr. Omoruyi said.

“We hope to learn more about the origins of the cavities we have already detected and find the cavities we expect to find on the other side of the black hole.”

a paper Regarding the survey results, astrophysical journal.

_____

Omase Omorui other. 2024. A “string bead” star formation associated with one of the most powerful she-AGN outbursts observed in the Cool Core Galaxy Cluster. APJ, in press. arXiv: 2312.06762

Source: www.sci.news

Webb finds small, free-floating brown dwarf in star-forming cluster IC 348

Posted on by
Reply
The newly discovered brown dwarf is estimated to have a mass three to four times that of Jupiter, making it a strong candidate for the lowest mass free-floating brown dwarf ever directly imaged.

This image from Webb’s NIRCam instrument shows the central portion of star cluster IC 348. Image credits: NASA / ESA / CSA / STScI / K. Luhman, Pennsylvania State University / C. Alves de Oliveira, ESA.

Brown dwarfs are cold, dark objects that are between the size of gas giant planets and Sun-like stars.

These objects, also known as failed stars, have star-like properties even though they are too small to sustain hydrogen fusion reactions in their cores.

Typically, their masses are between 11 and 16 Jupiter (the approximate mass that can sustain deuterium fusion) and 75 and 80 Jupiter (the approximate mass that can sustain hydrogen fusion).

“One of the basic questions you’ll find in any astronomy textbook is: What is the smallest star? That’s what we’re trying to answer,” said Kevin, an astronomer at Penn State University.・Dr. Luman said.

The newly discovered brown dwarf resides in IC 348, a star cluster 1,000 light-years away in the constellation Perseus.

The cluster, also known as Collinder 41, Gingrich 1, and Theia 17, contains nearly 400 stars and is about 5 million years old.

IC 348 is part of the larger Perseus star-forming region, and although it is normally invisible to the naked eye, it shines brightly when viewed at infrared wavelengths.

Dr. Luhmann and his colleagues used the following method to image the center of the star cluster. Webb’s NIRCam device Identify brown dwarf candidates based on their brightness and color.

They followed up on the most promising targets using: Webb’s NIRSpec microshutter array.

This process created three interesting targets with masses between three and eight Jupiters and surface temperatures between 830 and 1,500 degrees Celsius.

Computer models suggest that the smallest of these weighs just three to four times as much as Jupiter.

ESA astronomer Dr Catalina Alves de Oliveira said: “With current models, it is very easy to create a giant planet in a disk around a star.”

“But in this cluster, the object is unlikely to form as a disc, but instead as a star, with three Jupiters having a mass 300 times less than the Sun.”

“Then we have to ask how the star formation process takes place at such a very small mass.”

Two of the brown dwarfs identified by the research team exhibit spectral signatures of unidentified hydrocarbons, molecules that contain both hydrogen and carbon atoms.

The same infrared signature was detected in the atmospheres of Saturn and its moon Titan by NASA’s Cassini mission.

It has also been observed in the interstellar medium, the gas between stars.

“This is the first time this molecule has been detected in the atmosphere of an object outside our solar system,” Dr de Oliveira said.

“Models for brown dwarf atmospheres do not predict their existence. We are observing objects that are younger and have lower masses than ever before, and we are seeing something new and unexpected.” .”

a paper Regarding the survey results, astronomy magazine.

_____

KL Luman other. 2023. JWST survey of planetary mass brown dwarfs in IC 348. A.J. 167, 19; doi: 10.3847/1538-3881/ad00b7

Source: www.sci.news

A cluster of stripped helium stars found in the Magellanic Cloud by astronomers

Posted on by
Reply

Removing the hydrogen-rich layer from a main-sequence star exposes the helium-rich core. Such stripped helium stars are known at high and low masses, but not at intermediate masses, despite theoretical predictions that they should be common. In a new study, astronomers at the University of Toronto and elsewhere used ultraviolet photometry to identify candidates for stripped helium stars in two nearby dwarf galaxies, the Large and Small Magellanic Clouds. We observed 25 such candidate stars using optical spectroscopy. Most of these systems have been shown to be binary systems, with the companion star likely stripping the helium star of its outer hydrogen-rich layer.

An artist’s impression of a large-scale binary system. Image credit: ESO / M. Kornmesser / SE de Mink.

The hydrogen-rich outer layers of massive stars can be removed by interactions with binary companions.

Theoretical models predict that this separation would produce a population of hot helium stars with masses between two and eight times the mass of the Sun, but only one such system has been identified to date.

“This was a very large and noticeable hole. If these stars turn out to be rare, it could affect supernovae, gravitational waves, light from distant galaxies, and our theories for all these different phenomena. The whole framework is wrong,” said Dr Maria Draut, an astronomer at the university. of Toronto.

“This discovery shows that these stars actually exist.”

“In the future, we will be able to perform even more detailed physics on these stars.”

“For example, predictions of how many neutron star mergers we will see depend on the properties of these stars, such as how much material is ejected by stellar winds.”

“In the past, people have estimated it, but now for the first time they will be able to measure it.”

Dr. Drout and her colleagues designed a new study to look at the ultraviolet part of the spectrum, where very hot stars emit most of their light.

Astronomers used data from the Swift Ultraviolet/Optical Telescope to collect the brightness of millions of stars in the Large and Small Magellanic Clouds, the two closest galaxies to Earth.

They developed the first wide-field UV catalog of the Magellanic Clouds and used UV photometry to detect systems with unusual UV emissions indicating the possible presence of stripped stars.

They acquired optical spectroscopy with the Magellan Telescope at the Las Campanas Observatory from 2018 to 2022 and conducted pilot studies on 25 objects.

These stripped stars had high temperatures (60,000 to 100,000 K), high surface gravity, and hydrogen-depleted surfaces. Sixteen stars also showed binary motion.

Drout and his co-authors propose that these stars will eventually explode as hydrogen-depleted supernovae.

These objects, like the gravitational wave-emitting objects detected from Earth by the LIGO experiment, are also thought to be necessary for the formation of neutron star mergers.

In fact, researchers believe that some of the objects in the current sample are neutron stars or stripped stars with black hole companions.

These objects are on the verge of becoming double neutron stars or neutron star and black hole systems that may eventually merge.

“Many stars are part of a cosmic dance with partners, orbiting each other in binary star systems,” says Dr. Bethany Ludwig. He is a student at the University of Toronto.

“They are not solitary giants, but part of a dynamic duo, interacting and influencing each other throughout their lives.”

“Our research sheds light on these fascinating relationships, revealing a universe far more interconnected and active than previously imagined.”

“Just as humans are social beings, stars, especially massive stars, are rarely lonely.”

of result appear in the diary science.

_____

MR Drought other. 2023. Observed population of intermediate-mass helium stars separated by binaries. Science 382 (6676): 1287-1291; doi: 10.1126/science.ade4970

Source: www.sci.news