Ann Arbor Times

A team of researchers from the University of Michigan has discovered a new dwarf galaxy named Andromeda XXXV. This satellite galaxy, found on the outskirts of the Andromeda Galaxy, is considered the smallest and dimmest satellite galaxy observed in this system so far. The discovery was led by Marcos Arias, an undergraduate student at the time, who is now a post-baccalaureate researcher in astronomy and physics.

The finding challenges existing theories about how galaxies evolve and survive through different epochs. "We still have a lot to discover," said Arias. "There are so many things that we still need to learn—even about what’s near to us—in terms of galaxy formation, evolution and structure."

Eric Bell, senior author of the study and professor at U-M's Department of Astronomy, emphasized that these satellite galaxies are significantly smaller than their host galaxies but are fully functional. "These are fully functional galaxies, but they’re about a millionth of the size of the Milky Way," Bell explained.

Andromeda XXXV was discovered using data from massive observational datasets followed by observations with the Hubble Space Telescope. The research team included members from various institutions such as the University of Chicago, Utah Valley University, Vatican Observatory, University of La Serena in Chile, University of Alabama, Montana State University and Leibniz Institute for Astrophysics Potsdam in Germany.

This discovery offers insights into star formation processes within small galaxies like Andromeda XXXV. "Most of the Milky Way satellites have very ancient star populations," said Arias. "What we’re seeing is that similar satellites in Andromeda can form stars up to a few billion years ago—around 6 billion years."

The study also contributes to understanding how star formation stops within these small systems. According to Bell: "With star formation lasting longer in Andromeda’s small companions...we’ve learned something qualitatively new about galaxy formation from them."

The universe's history plays a crucial role in understanding why certain small galaxies like Andromeda XXXV continue forming stars despite adverse conditions expected during certain cosmic periods. However, some questions remain unanswered regarding how such small systems managed prolonged star formation.

"I don’t have an answer," Bell admitted regarding why Andromeda XXXV continued forming stars beyond expectations given its size relative to other known factors affecting galactic development over time.

Organizations like NASA plan future missions aimed at discovering more satellite galaxies which may provide further clarity on these mysteries while researchers remain eager for forthcoming revelations as Arias noted: “It’s the universe,” he said. “There will always be something new to discover.”