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.
Galaxies are not islands in the cosmos. While globally the universe expands—driven by the mysterious "dark energy"—locally, galaxies cluster through gravitational interactions, forming the cosmic web held together by dark ...
Astronomy
Jan 7, 2025
0
78
Physicists have proposed a solution to a long-standing puzzle surrounding the GD-1 stellar stream, one of the most well-studied streams within the galactic halo of the Milky Way, known for its long, thin structure, and unusual ...
Astronomy
Jan 7, 2025
6
99
A new study in published in Physical Review Letters analyzes the most complete set of galaxy clustering data to test the ΛCDM model, revealing discrepancies in the formation of cosmic structures in the universe, hinting at ...
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 ...
Astronomy
Jan 1, 2025
0
339
Using the James Webb Space Telescope (JWST), an international team of astronomers has detected a new grand-design spiral galaxy as part of the PANORAMIC survey. The newfound galaxy, named Zhúlóng, is extremely massive and ...
This NASA/ESA Hubble Space Telescope image features the spiral galaxy NGC 2566, which sits 76 million light-years away in the constellation Puppis. A prominent bar of stars stretches across the center of this galaxy, and ...
Astronomy
Dec 23, 2024
0
83
The missing ingredient for cooking up stars in the same way you might steam your Christmas pudding has been spotted for the first time by astronomers. Much like a pressure cooker has a weight on top of its lid to keep the ...
Astronomy
Dec 19, 2024
1
156
Astronomers have discovered an important piece of the puzzle of how supermassive black holes were able to grow so quickly in the early universe: a special kind of active galactic nucleus so distant that its light has taken ...
Astronomy
Dec 18, 2024
0
197
NASA researchers have discovered a perplexing case of a black hole that appears to be "tipped over," rotating in an unexpected direction relative to the galaxy surrounding it. That galaxy, called NGC 5084, has been known ...
Astronomy
Dec 18, 2024
0
115
Scientists have spotted a massive black hole in the early universe that is "napping" after stuffing itself with too much food. Like a bear gorging itself on salmon before hibernating for the winter, or a much-needed nap after ...
Astronomy
Dec 18, 2024
9
330
