Dark Energy Camera Captures the Glittering Galaxies of the Antlia Cluster

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DECam Deep View of the Antlia Cluster

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Cosmic Gems Within the Antlia Cluster

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Ultra-compact Dwarf Galaxy in the Antlia Cluster

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Spiral Galaxy in the Antlia Cluster

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Elliptical Galaxy in the Antlia Cluster

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Galaxy Cluster in the Antlia Cluster

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Videos

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Cosmoview Episode 91: Dark Energy Camera Captures the Glittering Galaxies of the Antlia Cluster

 

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Cosmoview Episodio 91: Miles de galaxias capturadas en una sola foto desde Cerro Tololo

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Pan on the Antlia Cluster

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Zooming into the Antlia Cluster

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Thousands of sparkling galaxies revealed in new ultra-deep DECam image featuring the Antlia Cluster

NSF NOIRLab rings in the New Year with a glittering galaxyscape captured with the Department of Energy-fabricated Dark Energy Camera, mounted on the U.S. National Science Foundation Víctor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory in Chile, a Program of NSF NOIRLab. This ultra-deep view of the Antlia Cluster reveals a spectacular array of galaxy types amongst the hundreds that make up its population.

Galaxy clusters are some of the largest known structures in the known Universe. Current models suggest that these massive structures form as clumps of dark matter and the galaxies that form within them are pulled together by gravity to form groups of dozens of galaxies, which in turn merge to form clusters of hundreds, even thousands. One such group is the Antlia Cluster (Abell S636), located around 130 million light-years from Earth in the direction of the constellation Antlia (the Air Pump).

This image was taken with the 570-megapixel Department of Energy-fabricated Dark Energy Camera (DECam), mounted on the U.S. National Science Foundation (NSF) Víctor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory in Chile, a Program of NSF NOIRLab. It captures only a portion of the 230 galaxies that so far have been found to make up the Antlia Cluster, as well as thousands of background galaxies. DECam’s ultra-deep view showcases the variety of galaxy types within and beyond the cluster in incredible detail.

Several Programs of NOIRLab (NOAO before 2019) have contributed observations of the Antlia Cluster over the past 20 years. Scientists from Chile have used both the Blanco telescope (with its predecessor camera MOSAIC II) and the Gemini South telescope, one half of the International Gemini Observatory, funded in part by NSF and operated by NSF NOIRLab, to examine the cluster through the Antlia Cluster Project. In more recent years, researchers have investigated the cluster from space- and ground-based observatories. These combined efforts have revealed a dynamic menagerie of rarer galaxy types within the cluster.

The Antlia Cluster is dominated by two massive elliptical galaxies — NGC 3268 (center) and NGC 3258 (lower right). These central galaxies are surrounded by a number of faint dwarf galaxies (see this finder chart showing the Altia Cluster in a different orientation). Researchers believe these two galaxies are in the process of merging, based on X-ray observations that revealed a ‘rope’ of globular clusters along the peak area of light between them. This may be evidence that the Antlia cluster is really two smaller clusters that are combining.

The cluster is rich in lenticular galaxies — a type of disk galaxy that has little interstellar matter and thus little ongoing star formation — and also hosts some irregular galaxies. A plethora of rarer, low-luminosity dwarf galaxies have been found in the cluster, including ultra-compact dwarfs, compact ellipticals, and blue compact dwarfs. The cluster may also contain dwarf spheroidal galaxies and the ultra-diffuse galaxy sub-type, though further investigations are needed to confirm them.

Many of these galaxy types have only been identified within the past few decades because of advances in observational equipment and data analysis techniques that can better capture the low luminosity and relatively smaller size of these galaxies. Evaluating galaxy types allows astronomers to plot the fine details of galaxy evolution, and some galaxies rich with dark matter provide further opportunities for astronomers to understand this mysterious substance that makes up 25% of the Universe.

The development of larger and more highly sensitized cameras like DECam allows astronomers to see the fainter details of these superstructures, such as the diffuse light between the cluster galaxies, which is a combination of intracluster light — the feeble glow of stars flung out into the gravitational field of the cluster by the churn of interacting galaxies — and faded light from the nearby Antlia Supernova Remnant discovered in 2002.

NSF–DOE Vera C. Rubin Observatory’s upcoming Legacy Survey of Space and Time will be the first astronomical survey to provide scientists with the data they need to detect intracluster light in thousands of galaxy clusters, unlocking clues to the distribution of dark matter around galaxy clusters and the evolutionary history of the Universe on large scales.

Source: NSF’s National Optical-Infrared Astronomy Research Laboratory (NOIRLab)/News

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More information

NSF NOIRLab, the U.S. National Science Foundation center for ground-based optical-infrared astronomy, operates the International Gemini Observatory (a facility of NSF, NRC–Canada, ANID–Chile, MCTIC–Brazil, MINCyT–Argentina, and KASI–Republic of Korea), NSF Kitt Peak National Observatory (KPNO), NSF Cerro Tololo Inter-American Observatory (CTIO), the Community Science and Data Center (CSDC), and NSF–DOE Vera C. Rubin Observatory (in cooperation with DOE’s SLAC National Accelerator Laboratory). It is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with NSF and is headquartered in Tucson, Arizona.

The scientific community is honored to have the opportunity to conduct astronomical research on I’oligam Du’ag (Kitt Peak) in Arizona, on Maunakea in Hawai‘i, and on Cerro Tololo and Cerro Pachón in Chile. We recognize and acknowledge the very significant cultural role and reverence of I’oligam Du’ag (Kitt Peak) to the Tohono O’odham Nation, and Maunakea to the Kanaka Maoli (Native Hawaiians) community.

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Links

• Explore the Antlia Cluster in more detail
• Photos of the Víctor M. Blanco 4-meter Telescope
• Videos of the Víctor M. Blanco 4-meter Telescope
• Photos of DECam
• Images taken by DECam
• Check out other NOIRLab Photo Releases

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Contacts

Josie Fenske
Jr. Public Information Officer
NSF NOIRLab
Email: josie.fenske@noirlab.edu

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MIT scientists pin down the origins of a fast radio burst

An artist's illustration of a neutron star emitting a radio beam from within its magnetic environment. As the radio waves travel through dense plasma within the galaxy, they split into multiple paths, causing the observed signal to flicker in brightness. Credits: Credit: Daniel Liévano, edited by MIT News

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The fleeting cosmic firework likely emerged from the turbulent magnetosphere around a far-off neutron star.

Fast radio bursts are brief and brilliant explosions of radio waves emitted by extremely compact objects such as neutron stars and possibly black holes. These fleeting fireworks last for just a thousandth of a second and can carry an enormous amount of energy — enough to briefly outshine entire galaxies.

Since the first fast radio burst (FRB) was discovered in 2007, astronomers have detected thousands of FRBs, whose locations range from within our own galaxy to as far as 8 billion light-years away. Exactly how these cosmic radio flares are launched is a highly contested unknown.

Now, astronomers at MIT have pinned down the origins of at least one fast radio burst using a novel technique that could do the same for other FRBs. In their new study, appearing today in the journal Nature, the team focused on FRB 20221022A — a previously discovered fast radio burst that was detected from a galaxy about 200 million light-years away.

The team zeroed in further to determine the precise location of the radio signal by analyzing its “scintillation,” similar to how stars twinkle in the night sky. The scientists studied changes in the FRB’s brightness and determined that the burst must have originated from the immediate vicinity of its source, rather than much further out, as some models have predicted.

The team estimates that FRB 20221022A exploded from a region that is extremely close to a rotating neutron star, 10,000 kilometers away at most. That’s less than the distance between New York and Singapore. At such close range, the burst likely emerged from the neutron star’s magnetosphere — a highly magnetic region immediately surrounding the ultracompact star.

The team’s findings provide the first conclusive evidence that a fast radio burst can originate from the magnetosphere, the highly magnetic environment immediately surrounding an extremely compact object.

“In these environments of neutron stars, the magnetic fields are really at the limits of what the universe can produce,” says lead author Kenzie Nimmo, a postdoc in MIT’s Kavli Institute for Astrophysics and Space Research. “There’s been a lot of debate about whether this bright radio emission could even escape from that extreme plasma.”

“Around these highly magnetic neutron stars, also known as magnetars, atoms can’t exist — they would just get torn apart by the magnetic fields,” says Kiyoshi Masui, associate professor of physics at MIT. “The exciting thing here is, we find that the energy stored in those magnetic fields, close to the source, is twisting and reconfiguring such that it can be released as radio waves that we can see halfway across the universe.”

The study’s MIT co-authors include Adam Lanman, Shion Andrew, Daniele Michilli, and Kaitlyn Shin, along with collaborators from multiple institutions.

Burst size

Detections of fast radio bursts have ramped up in recent years, due to the Canadian Hydrogen Intensity Mapping Experiment (CHIME). The radio telescope array comprises four large, stationary receivers, each shaped like a half-pipe, that are tuned to detect radio emissions within a range that is highly sensitive to fast radio bursts.

Since 2020, CHIME has detected thousands of FRBs from all over the universe. While scientists generally agree that the bursts arise from extremely compact objects, the exact physics driving the FRBs is unclear. Some models predict that fast radio bursts should come from the turbulent magnetosphere immediately surrounding a compact object, while others predict that the bursts should originate much further out, as part of a shockwave that propagates away from the central object.

To distinguish between the two scenarios, and determine where fast radio bursts arise, the team considered scintillation — the effect that occurs when light from a small bright source such as a star, filters through some medium, such as a galaxy’s gas. As the starlight filters through the gas, it bends in ways that make it appear, to a distant observer, as if the star is twinkling. The smaller or the farther away an object is, the more it twinkles. The light from larger or closer objects, such as planets in our own solar system, experience less bending, and therefore do not appear to twinkle.

The team reasoned that if they could estimate the degree to which an FRB scintillates, they might determine the relative size of the region from where the FRB originated. The smaller the region, the closer in the burst would be to its source, and the more likely it is to have come from a magnetically turbulent environment. The larger the region, the farther the burst would be, giving support to the idea that FRBs stem from far-out shockwaves.

Twinkle pattern

To test their idea, the researchers looked to FRB 20221022A, a fast radio burst that was detected by CHIME in 2022. The signal lasts about two milliseconds, and is a relatively run-of-the-mill FRB, in terms of its brightness. However, the team’s collaborators at McGill University found that FRB 20221022A exhibited one standout property: The light from the burst was highly polarized, with the angle of polarization tracing a smooth S-shaped curve. This pattern is interpreted as evidence that the FRB emission site is rotating — a characteristic previously observed in pulsars, which are highly magnetized, rotating neutron stars.

To see a similar polarization in fast radio bursts was a first, suggesting that the signal may have arisen from the close-in vicinity of a neutron star. The McGill team’s results are reported in a companion paper today in Nature.

The MIT team realized that if FRB 20221022A originated from close to a neutron star, they should be able to prove this, using scintillation.

In their new study, Nimmo and her colleagues analyzed data from CHIME and observed steep variations in brightness that signaled scintillation — in other words, the FRB was twinkling. They confirmed that there is gas somewhere between the telescope and FRB that is bending and filtering the radio waves. The team then determined where this gas could be located, confirming that gas within the FRB’s host galaxy was responsible for some of the scintillation observed. This gas acted as a natural lens, allowing the researchers to zoom in on the FRB site and determine that the burst originated from an extremely small region, estimated to be about 10,000 kilometers wide.

“This means that the FRB is probably within hundreds of thousands of kilometers from the source,” Nimmo says. “That’s very close. For comparison, we would expect the signal would be more than tens of millions of kilometers away if it originated from a shockwave, and we would see no scintillation at all.”

“Zooming in to a 10,000-kilometer region, from a distance of 200 million light years, is like being able to measure the width of a DNA helix, which is about 2 nanometers wide, on the surface of the moon,” Masui says. “There’s an amazing range of scales involved.”

The team’s results, combined with the findings from the McGill team, rule out the possibility that FRB 20221022A emerged from the outskirts of a compact object. Instead, the studies prove for the first time that fast radio bursts can originate from very close to a neutron star, in highly chaotic magnetic environments.

“These bursts are always happening, and CHIME detects several a day,” Masui says. “There may be a lot of diversity in how and where they occur, and this scintillation technique will be really useful in helping to disentangle the various physics that drive these bursts.”

This research was supported by various institutions including the Canada Foundation for Innovation, the Dunlap Institute for Astronomy and Astrophysics at the University of Toronto, the Canadian Institute for Advanced Research, the Trottier Space Institute at McGill University, and the University of British Columbia.

Jennifer Chu | MIT News

Source: Massachusetts Institute of Technology (MIT)News

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Towards direct observation of large samples of intergalactic filaments in the early universe

One quasar of the sample embedded into extended Lyman alpha emission (cyan), which reaches the edge of the circumgalactic medium of its host galaxy. The uncovered filamentary structure is stretched in the direction of the second quasar of the pair (not shown). Multiple further sources are visible in this field, which are not physically associated with the quasar pair; these lie between Earth and the observed quasar. © MPA

This plot shows the alignment of the Lyman alpha nebulae with the quasar pair direction. An angle of zero degrees corresponds to perfect alignment. In the sample studied, all large nebulae (extending into the circumgalactic medium by more than 200,000 light years) trace the quasar pair direction. This trend is not driven by the quasar luminosity (colour of the points) or the distance between the quasar pairs (size of the dots). This shows that the Lyman alpha nebulae indeed trace the cosmic web filaments. © MPA

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The distribution of matter in the universe is predicted by supercomputer simulations to occur in a network of filaments, known as the "cosmic web", where galaxies form and evolve. The vast majority of this intricate structure is in the form of diffuse hydrogen gas, so rarefied that it is extremely challenging to observe it directly. A collaboration led by MPA researchers has targeted the active supermassive black holes of galaxy pairs at close separations to reveal the connecting filamentary structures of the cosmic web in the early universe. The results are promising and unveil evidence for such structures stretching between the observed pairs, ultimately providing excellent targets for future ultra-deep observations.

Galaxies are embedded in large reservoirs of gas bound to them by gravity, the so-called 'circumgalactic medium'. Like all gas in the universe, it mainly consists of hydrogen and helium with traces of other elements that are produced in stars and ejected from the galaxy disks in bubbles of hot gas or fast winds expanding into the circumgalactic medium. In turn, cool gas is funneled back into the galaxy in streams and can form new stars or feed the supermassive black hole at the galactic centre. Galaxies are not hermits though: large filamentary gas structures connect galaxies to their neighbours. This overall skeleton is called 'cosmic web' (see Monthly Highlight of June 2024), and galaxies can accrete additional material from its filaments to rejuvenate and grow. While simulations have explored this process very well, observational evidence of the filamentary cosmic web is sparse and mainly indirect, e.g. inferred from the observed position of galaxies in the local universe or by how the cosmic web absorbs light from bright background sources.

The areas where multiple filaments of the cosmic web intersect are called 'nodes', typically inhabited by the most massive galaxies. In the early universe, 11.5 billion years ago, these massive galaxies are commonly pinpointed by quasars – a brief phase in these galaxies’ life cycle, when matter falling onto their central supermassive black holes powers exceptionally luminous events that easily outshine all stars in their host galaxy. Therefore quasars can act as powerful natural 'cosmic flashlights': Their radiation can reach far into the circumgalactic medium and the surrounding cosmic web, lighting up the hydrogen gas at a specific ultraviolet colour, the Lyman alpha wavelength.

Researchers from MPA have now observed a sample of quasar pairs, i.e. two massive active galaxies in direct vicinity to each other, to unveil the Lyman alpha emission in their circumgalactic medium and in-between the galaxies (commonly referred to as 'Lyman alpha nebulae'). Extended emission is detected in most targeted systems (see example in Fig. 1) and the emission is preferentially aligned with the pair direction (see Fig. 2). These results are in line with expectations, if a cosmic web filament connects the two quasars and cool gas gets funneled directly from the filament through the circumgalactic medium down to the galactic disk.

Compared to other massive galaxies at this epoch, quasar pairs are embedded in smaller reservoirs of cool gas. Their circumgalactic medium actually resembles that of galaxies at a cosmic time one billion years later. Such an accelerated evolution might be caused by the rich environment inhabited by quasar pairs and/or by highly energetic processes connected to the accreting supermassive black holes, which could heat up the gas surrounding the galaxy and counteract the gas accretion.

This sample of quasar pair observations is the largest to date and represents the best collection of promising targets for directly studying the emission of the cosmic web in the early universe with future ultra-deep observations. More and more observations of the intricate web of cosmic filaments will become available in the near future.

Source: Max Planck Institute for Astrophysics/News

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Author:

Eileen Herwig
PhD student
tel:2344
eherwig@mpa-garching.mpg.de

Original publication

Eileen Herwig
Arrigoni Battaia, Fabrizio;
González Lobos, Jay; et al.
QSO MUSEUM: II. Search for extended Lyα emission around eight z ∼ 3 quasar pairs
A&A, 691, A210 (2024)

Source | DOI

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