Galaxies are gravitationally bound, large-scale astrophysical systems composed primarily of dark matter, stars, stellar remnants, gas, and dust, often embedded in extended dark matter halos. They exhibit diverse morphologies, including spiral, elliptical, and irregular types, and span mass scales from roughly 10⁷ to over 10¹² solar masses. Their internal dynamics are governed by gravity and angular momentum distribution, with baryonic components organized into disks, bulges, and halos, and frequently hosting central supermassive black holes. Galaxies are fundamental units of cosmic structure formation, participating in hierarchical assembly, mergers, and interactions within larger environments such as groups, clusters, and filaments of the cosmic web.
Using ESA's XMM-Newton satellite, astronomers from Stanford University and elsewhere have conducted deep X-ray observations of a nearby galaxy known as NGC 3221. The new observational campaign detected a faint active galactic ...
A team of astronomers from the International Center for Radio Astronomy Research (ICRAR) has released new data from an extensive galaxy evolution survey that found a galaxy's "neighborhood" plays a major role in how it changes ...
Astronomy
Nov 25, 2025
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In the early 1930s, Swiss astronomer Fritz Zwicky observed galaxies in space moving faster than their mass should allow, prompting him to infer the presence of some invisible scaffolding—dark matter—holding the galaxies together. ...
Astronomy
Nov 25, 2025
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An expanding universe complicates this picture just a little bit, because the universe absolutely refuses to be straightforward. Objects are still emitting light, and that light takes time to travel from them over to here, ...
Astronomy
Nov 24, 2025
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The European Space Agency's Euclid mission—designed to map the geometry of the dark universe with unprecedented precision—continues to deliver its first scientific insights. The Euclid Consortium has published a fresh set ...
Astronomy
Nov 20, 2025
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Tracking down black holes at the center of dwarf galaxies has proven difficult. In part it is because they have a tendency to "wander" and are not located at the galaxy's center. There are plenty of galaxies that might contain ...
Astronomy
Nov 19, 2025
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Using the Atacama Large Millimeter/submillimeter Array (ALMA), an international team of astronomers has inspected a distant galaxy designated MACS0416_Y1. Results of the observations, presented Nov. 11 on the arXiv pre-print ...
All motion is relative. That simple fact makes tracking the motion of distant objects outside our galaxy particularly challenging. For example, there has been a debate among astronomers for decades about the path that one ...
Astronomy
Nov 18, 2025
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Using the Two-meter Twin Telescope (TTT3), Spanish astronomers have conducted deep optical imaging of an isolated dwarf galaxy known as NGC 6789. Results of the new observations, presented November 10 on the arXiv preprint ...
Quasars acting as strong gravitational lenses are among the rarest finds in astronomy. Out of nearly 300,000 quasars cataloged in the Sloan Digital Sky Survey, only twelve candidates were identified, and just three confirmed. ...
Astronomy
Nov 17, 2025
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