Astronomers have discovered new evidence for the properties of giant high-energy gas bubbles that lie far above and below the center of the Milky Way galaxy. In a recently published study Nature Astronomy A team led by Ohio State University scientists has succeeded in showing that the shells of these structures, dubbed “eRosita bubbles” after they were discovered by the eRosita X-ray telescope, are more complex than previously thought.

Although they bear a striking resemblance to Fermi bubbles in shape, eRosita bubbles are larger and more energetic than their counterparts. The study’s lead author and former Ohio resident Anjali Gupta said it offers a fascinating opportunity to examine the history of star formation, known collectively as “galactic bubbles” because of their size and location, and to uncover new clues about how the Milky Way formed. He’s a state postdoctoral fellow who is currently a professor of astronomy at Columbus State College.

These bubbles are found in the gas surrounding galaxies in a region called the periphery of the galaxy.

“Our goal was to learn more about the galactic environment, which is a crucial place for understanding how our galaxy formed and evolved,” Gupta said. Said. “Most of the regions we studied were in the bubble region, so we wanted to see how different the bubbles were compared to regions far from the bubbles.”

Previous studies have suggested that these bubbles are heated by the effect of gas escaping from the galaxy, but the main findings of this paper show that the temperature of the gas inside the bubbles is not significantly different from the temperatures outside.

“We were surprised to find that the temperature inside and outside the bubble zone was the same,” Gupta said. Said. The study also shows that these bubbles are very bright not because they are hotter than their surroundings, but because they are filled with extremely dense gas.

Gupta and Smita Mathur, study co-authors and professors of astronomy at Ohio State, conducted their analysis using observations made by the Suzaku satellite, a joint mission of NASA and the Japan Aerospace Exploration Agency.

By analyzing 230 archival observations made between 2005 and 2014, the researchers were able to characterize the diffuse emission (electromagnetic emission from very low-density gas) of galactic bubbles as well as other hot gases surrounding them.

Although the origin of these bubbles is debated in the scientific literature, this study is the first to begin addressing it, Mathur said. As the team found abundant non-solar neon-oxygen and magnesium-oxygen ratios in the envelopes, their results strongly suggest that galactic bubbles were initially formed by nuclear star-forming activity or energy input provided by massive stars and other species. . It is not caused by astrophysical phenomena and the activity of a supermassive black hole.

“Our data support the theory that these bubbles are most likely formed by intense star formation at the center of the galaxy, as opposed to black hole activity that occurs at the center of the galaxy,” Mathur said. Said. To further investigate the implications of their discovery for other aspects of astronomy, the team hopes to use new data from other future space missions to continue characterizing the properties of these bubbles and find new ways to analyze the data they already have. . .

“Scientists really need to understand the formation of bubble structure, so we can better limit the temperature and emission rates we’re looking for by using different techniques to improve our models,” Gupta said. Said.

Other co-authors were Joshua Kingsbury and Sanskriti Das from Ohio State and Yair Krongold from the National Autonomous University of Mexico.