Showing posts with label Abell 3667. Show all posts
Showing posts with label Abell 3667. Show all posts

Monday, August 11, 2025

DECam’s Deep View of Abell 3667 Illuminates the Past of a Galaxy Cluster and the Future of Astronomical Imaging

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DECam’s Deep View of Abell 3667

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Excerpts From DECam’s Deep View of Abell 3667

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Labeled view of Abell 3667



Videos

Pan on Abell 3667
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Pan on Abell 3667

Zooming into Abell 3667
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Zooming into Abell 3667

Cosmoview Episode 102: DECam’s Deep View of Abell 3667 (horizontal)
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Cosmoview Episode 102: DECam’s Deep View of Abell 3667 (horizontal)

Cosmoview Episode 102: DECam’s Deep View of Abell 3667 (vertical)
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Cosmoview Episode 102: DECam’s Deep View of Abell 3667 (vertical)

Episodio 102 de Cosmoview: La imagen pas profunda de Abell 3667 lograda por DECam (horizontal)
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Episodio 102 de Cosmoview: La imagen pas profunda de Abell 3667 lograda por DECam (horizontal) in English only

Episodio 102 de Cosmoview: La imagen pas profunda de Abell 3667 lograda por DECam (vertical)
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Episodio 102 de Cosmoview: La imagen pas profunda de Abell 3667 lograda por DECam (vertical)



Dark Energy Camera captures elusive intracluster light in Abell 3667, providing a glimpse into its history as a merging galaxy cluster and a preview of what NSF–DOE Vera C. Rubin Observatory will deliver

An actively merging galaxy cluster is featured in this image assembled from a total of 28 hours of observations with the 570-megapixel 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, a Program of NSF NOIRLab. The image gives a tantalizing hint of how intracluster light will be revealed by NSF–DOE Vera C. Rubin Observatory’s Legacy Survey of Space and Time.

Galaxy clusters are among the largest structures in our Universe, consisting of hundreds or thousands of galaxies that have become gravitationally bound together over billions of years. Astrophysicists have long been eager to understand the formation of these imposing structures. The histories of galaxy clusters not only help us understand how the Universe formed, but they also provide constraints on the properties of dark matter — an invisible material that doesn’t emit or reflect light and is found in high concentrations around clusters of galaxies.

One clue astronomers look for to understand the history of a galaxy cluster is intracluster light — the faint glow emitted by stars that have been stripped from their original galaxies by the immense gravity of a forming galaxy cluster. These stars serve as whispering evidence of past galactic interactions, though most existing telescopes and cameras struggle to capture them.

The delicate intracluster light of galaxy cluster Abell 3667 shines prominently in this elusive image captured by the 570-megapixel Department of Energy-fabricated Dark Energy Camera (DECam), mounted on the U.S. National Science Foundation Víctor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF NOIRLab. Abell 3667 is more than 700 million light-years away from us. The great majority of faint sources of light in this image are very distant galaxies, and not foreground stars in our own galaxy.

Within Abell 3667, two smaller galaxy clusters are actively merging together, evidenced by the glowing bridge (yellow) of stars stretching across the center of this image. This bridge connects the hearts of the two galaxy clusters, known as their brightest cluster galaxies, and forms out of material stripped from the galaxies as they merge to form one massive conglomerate.

Not only is this sequined sky full of faraway galaxies, but faint foreground features are also illuminated from its long exposure time. Milky Way cirrus, or integrated flux nebulae, are faint, wispy clouds of interstellar dust that can be seen as faint bluish strands criss-crossing the image. These cirrus are patches of dust illuminated by the combined light of stars within our own galaxy. They appear as diffuse, filamentary structures that can cover large areas of the sky.

Created from a total of 28 hours of observations, this is the deepest image of Abell 3667 ever assembled. Such a long exposure is necessary to detect the faint, diffuse brightness of the cirrus, which is typically only a small percent of the brightness of the night sky, as well as the even fainter intracluster light.

The way that scientists study intracluster light will soon be revolutionized with the NSF–DOE Vera C. Rubin Observatory, a major new scientific facility jointly funded by the U.S. National Science Foundation and the U.S. Department of Energy's Office of Science that is scheduled to begin the Legacy Survey of Space and Time (LSST) later this year.

Using the largest camera ever made, Rubin will image the entire southern hemisphere sky every few nights for ten years. Within the treasure trove of data that the LSST produces will be millions of high-resolution images of distant galaxy clusters. These images can then be stacked to create ultra-long-exposure masterpieces like the one above that reveal a galaxy cluster’s intracluster light.

DECam’s image of Abell 3667 serves as a preview of what Rubin will capture by year eight of the LSST. But rather than a snapshot of a single galaxy cluster, Rubin will capture this level of depth across the entire southern hemisphere sky. Scientists expect that future studies of intracluster light with Rubin data will reveal new features and enable detailed studies of the stellar populations of these features.




More information

The data used to create this image appears in the paper titled “The Intracluster Light of Abell 3667: Unveiling an Optical Bridge in LSST Precursor Data,” published in The Astrophysical Journal Letters. DOI: 10.3847/2041-8213/ade8f1

This research draws upon DECam data as distributed by the Astro Data Archive at NSF NOIRLab.

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 to the Tohono O’odham Nation, and Maunakea to the Kanaka Maoli (Native Hawaiians) community.

The Dark Energy Camera was designed specifically for
DES. It was funded by the Department of Energy (DOE) and was built and tested at DOE's Fermilab.



Links



Contacts

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


Wednesday, April 08, 2020

Universe's Expansion May Not Be The Same In All Directions

Abell 2199, RXCJ1504.1-0248, Abell 85, Abell 3667
Credit: NASA/CXC/Univ. of Bonn/K. Migkas et al.





This graphic contains a map of the full sky and shows four of the hundreds of galaxy clusters that were analyzed to test whether the Universe is the same in all directions over large scales, as described in our latest press release. Galaxy clusters are the largest objects in the Universe bound by gravity and astronomers can use them to measure important cosmological properties. This latest study uses data from NASA's Chandra X-ray Observatory and ESA's XMM-Newton to investigate whether or not the Universe is "isotropic."

The sky map in this schematic is in "galactic coordinates," with the plane of the Milky Way running along the middle (instead of the equator like is used for Earth). Galactic longitude runs in the horizontal, or "x" direction, and galactic latitude runs in the vertical, or "y" direction. The dark points show the location in the sky map of the 313 galaxy clusters observed with Chandra and XMM-Newton and included in this study. The four Chandra images of galaxy clusters from the new study are, in a clockwise direction from the top left, Abell 2199, RXCJ1504.1-0248, Abell 3667 and Abell 85. Galaxy clusters with galactic latitudes less than 20 degrees were not included in the survey to avoid obscuration from the Galaxy itself, which has most of its stars, gas and dust along a thin plane. Similarly, galaxy clusters behind two nearby galaxies, the Small Magellanic Cloud and the Large Magellanic Cloud, and behind the Virgo galaxy cluster were not included to avoid obscuration.

A2199, RXCJ1504.1-0248, A85, A3667
Credit: NASA/CXC/Univ. of Bonn/K. Migkas et al.

Astronomers generally agree that after the Big Bang, the cosmos has continuously expanded like a baking loaf of raisin bread. As the bread bakes, the raisins (which represent cosmic objects like galaxies and galaxy clusters) all move away from one another as the entire loaf (representing space) expands. With an even mix the expansion should be uniform in all directions, as it should be with an isotropic Universe.

This latest test uses a powerful, novel and independent technique and suggests the concept of an isotropic Universe may not entirely fit. The study capitalizes on the relationship between the temperature of the hot gas pervading a galaxy cluster and the amount of X-rays it produces, known as the cluster's X-ray luminosity. The higher the temperature of the gas in a cluster, the higher the X-ray luminosity is. Once the temperature of the cluster gas is measured, the X-ray luminosity can be estimated. This method is independent of cosmological quantities, including the expansion speed of the Universe.

Once they estimated the X-ray luminosities of their clusters using this technique, scientists then calculated luminosities using a different method that does depend on cosmological quantities, including the Universe's expansion speed. The results gave the researchers apparent expansion speeds across the whole sky — revealing that the Universe appears to be moving away from us faster in some directions than others.

The authors of this new study came up with two possible explanations for their results that involve cosmology. One of these explanations is that large groups of galaxy clusters might be moving together, but not because of cosmic expansion. For example, it is possible some nearby clusters are being pulled in the same direction by the gravity of groups of other galaxy clusters. If the motion is rapid enough it could lead to errors in estimating the luminosities of the clusters.

A second possible explanation is that the Universe is not actually the same in all directions. One intriguing reason could be that dark energy — the mysterious force that seems to be driving acceleration of the expansion of the Universe — is itself not uniform. In other words, the X-rays may reveal that dark energy is stronger in some parts of the Universe than others, causing different expansion rates.

Either of these two cosmological explanations would have significant consequences. The astronomical community must perform other scrutinized tests obtaining consistent results every time to truly know if the concept of an isotropic Universe should be reconsidered.

A paper describing these results will appear in the April 2020 issue of the journal Astronomy and Astrophysics and is available online. The authors are Konstantinos Migkas (University of Bonn, Germany), Gerrit Schellenberger (Center for Astrophysics | Harvard & Smithsonian), Thomas Reiprich, Florian Pacaud and Miriam Elizabeth Ramos-Ceja (University of Bonn), and Lorenzo Lovisari (CfA).

NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra's science and flight operations.




Fast Facts for Abell 85:

Scale: Image is about 15 arcminutes (3 million light years) across.
Category: Cosmology/Deep Fields/X-ray Background, Groups & Clusters of Galaxies
Coordinates (J2000): RA 00h 42m 50.7s | Dec -09° 38´ 45"
Constellation: Cetus
Observation Date: 12 pointings between September 2004 through August 2013
Observation Time: 65 hours (2 days 17 hours)
Obs. ID: 4881-4888, 15173, 16264, 15174, 16263
Instrument: ACIS
References: Migkas, K. et al., 2020, A&A; arXiv:2004.03305
Color Code: X-ray: Magenta
Distance Estimate: About 760 million light years (z=0.056)