Hubble telescope's new image captures galactic merger 14.5mn light-years away
NASA's Hubble Space Telescope has captured an image of the irregular dwarf galaxy NGC 5238. This galaxy, located a staggering 14.5 million light-years away from Earth, resides in the constellation Canes Venatici. Despite its seemingly simple, blob-like appearance that resembles an oversized star cluster more than a typical galaxy, NGC 5238's structure is complex and currently under extensive research. Scientists believe that this dwarf galaxy must have gone through a potential galactic merger with another smaller satellite galaxy.
NGC 5238: A galaxy of countless stars and complex structure
The Hubble image reveals a multitude of stars within the galaxy NGC 5238, along with its associated globular clusters. These bright spots, both inside and around the galaxy, are teeming with even more stars. Astronomers theorize that this dwarf irregular galaxy may have had a close encounter with another galaxy as recently as a billion years ago, an event suggested by its distorted shape.
Traces of galactic interaction in NGC 5238's distorted shape
During the theorized interaction between NGC 5238 and another galaxy, their respective star distributions were distorted due to gravitational forces. However, no nearby galaxy could have caused this disturbance, leading astronomers to believe that NGC 5238 consumed a smaller satellite galaxy. The search is now on for traces of this devoured galaxy by examining the population of stars within NGC 5238, a task made possible by Hubble's superior resolution.
Searching for signs of a consumed galaxy
Indicators of the smaller, consumed galaxy within NGC 5238 would include groups of stars with different properties from most of the galaxy's other stars. These differences suggest that these stars were originally formed in a separate galaxy. Another sign would be an abrupt burst of star formation that occurred around the same time as the theorized merger, providing further evidence for this galactic interaction.
Key to understanding galaxy formation and evolution
Despite their miniature size and unremarkable appearance, dwarf galaxies like NGC 5238 play a significant role in our understanding of galaxy formation and evolution. One main theory claims that galaxies formed 'bottom-up' in a hierarchical fashion: small galaxies and star clusters were the first to form out of gas and dark matter. Over time, gravity gradually assembled these smaller objects inside galaxy clusters and superclusters, and shaped the biggest structures we see in the universe today.
