JWST Captures Unprecedented Detail of Colliding Dwarf Galaxies, Offering Clues to Early Universe Formation
WASHINGTON – New images from the James Webb Space Telescope (JWST) reveal a spectacular view of two dwarf galaxies, NGC 4490 and NGC 4485, currently undergoing a cosmic collision approximately 24 million light-years from Earth. The observations are providing astronomers with valuable insights into the formation and evolution of galaxies in the early universe.
Dwarf galaxies, characterized by thier low mass, high gas content, and minimal metal composition, are considered analogous to the first galaxies. The interaction between NGC 4490 and NGC 4485 is marked by a prominent gas bridge, a flow of young stars, and ongoing gravitational reshaping of both galaxies.
The European Space Agency (ESA) released the JWST images, showcasing NGC 4490 dominating the left side of the frame with dust and young stars, while NGC 4485 shines on the top right. A luminous bridge of gas and dust connects the two, speckled with bluish clusters of new stars contrasting with the reddish glow of warm interstellar dust.ESA notes that this interaction is triggering a surge in star formation.
“Aside from the Milky Way’s two dwarf companions, the Large and Small Magellanic Clouds, this is the closest known system of interacting dwarf galaxies, where astronomers can directly observe gas bridges and their stellar populations,” ESA officials stated.
While previously studied with the Hubble Telescope, JWST’s infrared capabilities have revealed previously unseen details, including the fine structure of gas flowing between the galaxies and individual stars within them. Researchers are now able to map the locations of stars of different ages, tracing the timeline of the galactic interaction.
Analysis suggests NGC 4490 and NGC 4485 passed very closely approximately 200 million years ago.During this encounter, NGC 4490 drew gas from NGC 4485, forming the visible gas bridge and initiating a wave of star formation, some of which occurred as recently as 30 million years ago.
“By capturing the history of the cosmic dance of NGC 4490 and NGC 4485, Webb reveals new details about how dwarf galaxies interact, giving us a picture of how small galaxies grow and evolve,” ESA added.
