All articles tagged with #dwarf galaxies
A comprehensive census of over 8,000 nearby galaxies finds that active galactic nuclei are more common in dwarf galaxies than previously thought—roughly 2–5%—though far less than in mid-sized or large galaxies, suggesting a mass-dependent increase in AGN activity and underscoring the need for improved detection of faint black holes.
A JWST-backed study using gravitational lensing of galaxy cluster Abell 2744 analyzes faint, distant galaxies from the Epoch of Reionization. It finds a drop-off in ultrafaint galaxies—faint-end suppression—contradicting the expectation that there should be many more tiny galaxies. The result implies early radiation heated surrounding gas, preventing star formation in low‑mass halos and challenging the idea that the smallest galaxies powered reionization; however, conclusions depend on the cluster's lens model, and more JWST data across additional clusters are needed to confirm whether this is a universal trend.
A recent study analyzing 12 dwarf galaxies provides strong evidence supporting the existence of dark matter, challenging alternative theories like Modified Newtonian Dynamics (MOND). The findings show that the gravitational fields of these galaxies cannot be explained by visible matter alone, reinforcing the dark matter hypothesis and narrowing the search for its nature.
A study analyzing the smallest and faintest galaxies supports the presence of dark matter over modified gravity theories like MOND, showing that their gravitational behavior cannot be explained by visible matter alone and challenging previous assumptions about galaxy dynamics.
Astronomers discovered a massive, nearly invisible gas bridge and a record-breaking tail connecting two dwarf galaxies, NGC 4532 and DDO 137, located 53 million light-years away, providing insights into galaxy interactions and evolution.
Recent observations from the Hubble and James Webb Space Telescopes suggest that small dwarf galaxies played a crucial role in illuminating the early Universe during cosmic reionization, challenging previous assumptions that larger galaxies and black holes were the primary sources of ionizing radiation. This discovery highlights the importance of low-mass galaxies in shaping the Universe's evolution and opens new avenues for understanding our cosmic origins.
The article reviews the formation, properties, and significance of globular clusters and globular-cluster-like dwarfs in galaxy formation, highlighting their roles in understanding dark matter, galaxy evolution, and the early universe.
A new survey has discovered 355 mini galaxies, nearly tripling the known satellite galaxies around dwarf galaxies, which could provide valuable insights into dark matter and galaxy formation theories. The findings, made possible by the ID-MAGE survey, highlight the importance of small galaxies in understanding the universe's structure and evolution.
New research combining simulations and mathematical modeling suggests the Milky Way may have up to 100 undetected 'orphan' dwarf galaxies orbiting it, which could support the standard Lambda Cold Dark Matter (LCDM) cosmological model and help explain the discrepancy between observed and predicted satellite galaxies.
Astronomers using the JWST have discovered numerous tiny, energetic galaxies from about 800 million years after the Big Bang that likely played a key role in reionizing the universe, challenging previous ideas that larger galaxies or quasars were the main contributors.
The article explores the role of supermassive black holes in anchoring tiny galaxies, highlighting that smaller galaxies tend to be more dark matter dominated and may host supermassive black holes, with some evidence suggesting a connection between black holes and the structure of these faint galaxies, especially in the context of dark matter and galaxy formation.
A study reveals unexpected clustering patterns in dwarf galaxies that challenge the standard Cold Dark Matter model, suggesting dark matter may have complex, self-interacting properties, and highlighting the importance of dwarf galaxies in understanding cosmic structure formation.
A study using JWST and Hubble data reveals that faint dwarf galaxies, rather than massive galaxies or black holes, played a crucial role in the Universe's reionization, shedding light on the cosmic dawn and challenging previous assumptions about early galaxy formation.
NASA Astronaut Don Pettit captured stunning images of the Large and Small Magellanic Clouds, two dwarf galaxies, from the International Space Station (ISS). Despite common misconceptions, stars are visible from space, and Pettit used a homemade tracker to counteract the ISS's rapid movement, allowing for clear photos. His work highlights the challenges of space photography, such as dim stars and rapid motion. Additionally, Pettit shared a video of "cosmic fireflies," which are actually reflections from Starlink satellites, raising concerns about light pollution from satellite megaconstellations.
Astronomers have discovered a rare group of five interacting dwarf galaxies, located 117 million light years away, challenging the prevailing Lambda cold dark matter model of the universe. These galaxies, designated D1 to D5, are aligned in a straight line and show signs of mutual tidal interactions, with some sharing a common rotational direction. This unusual configuration raises questions about galaxy formation and evolution, potentially offering new insights into cosmological history. The findings were published in The Astrophysical Journal Letters.