Galactic Pressure Cooker: magnetic Fields Key to Star formation?
Imagine a cosmic pressure cooker, where the ingredients are gas and dust, and the resulting dish is a dazzling display of newborn stars.That’s the intriguing analogy used by astronomers to describe a groundbreaking finding: magnetic fields might potentially be the missing ingredient in the recipe for efficient star formation within merging galaxies.
For years, scientists have theorized about the role of magnetic fields in galactic evolution. Now,an international team led by Dr. David Clements of Imperial College London has found compelling evidence supporting this theory. Their research, published in the Monthly Notices of the Royal Astronomical society, reveals the presence of meaningful magnetic fields within the core of Arp 220, a pair of merging galaxies.
“This is the first time we’ve found evidence of magnetic fields in the core of a merger,” explains Dr. Clements. “But this discovery is just a starting point. We now need better models, and to see what’s happening in other galaxy mergers.”
Dr. Clements further elaborated on the significance of this discovery using a relatable analogy: “If you want to cook up a lot of stars (Christmas puddings) in a short period of time you need to squeeze lots of gas (or ingredients) together. This is what we see in the cores of mergers. But then, as the heat from young stars (or your cooker) builds, things can boil over, and the gas (or pudding mixture) gets dispersed,” he said. “To stop this happening, you need to add something to hold it all together — a magnetic field in a galaxy, or the lid and weight of a pressure cooker.”
The research team utilized the Submillimeter Array (SMA) on Maunakea, Hawaii, to peer deep into Arp 220, one of the brightest objects in the extragalactic far-infrared sky. The SMA’s ability to capture millimeter-wavelength light provided a unique window into the galaxy’s core, revealing the presence of these crucial magnetic fields.Arp 220, a result of two gas-rich spiral galaxies colliding, exhibits intense starburst activity, making it an ideal subject for this study.
this discovery sheds light on a long-standing mystery in astronomy: why some galaxies form stars at a much faster rate than others. The magnetic fields, it seems, act as a binding force, preventing the star-forming gas from dispersing as it heats up. While theoretical models have hinted at this possibility, this is the first observational evidence confirming the presence of these fields in a merging galaxy.
The team plans to use the Atacama Large Millimeter/submillimeter Array (ALMA) to expand their research, searching for similar magnetic fields in other ultraluminous infrared galaxies.This next phase of research promises to further illuminate the role of magnetic fields in the evolution of some of the most luminous galaxies in the universe.