An international team of scientists has solved one of the biggest cosmic mysteries. For years, why some galaxies stop forming new stars and turn into cosmic graveyards has baffled astronomers. They contain all the necessary ingredients to form new stars. So, why do they become dark and lifeless? Scientists liken it to having deserts in clouded regions where you would expect rain and vegetation. The reason is galactic warming.
What causes galactic warming?
Astronomers led by Edmond Cheung of the University of Tokyo have discovered a new class of galaxies called “red geysers.” The supermassive black holes at the center of such galaxies drive interstellar winds so energetic and hot that new stars just can’t form. These winds heat up the ambient gas, preventing the galaxy from cooling and condensing into stars.
Kevin Bundy, the co-author of the study, says galaxies begin as star-forming machines with a combination of gas and gravity that are key ingredients for star formation. The gravitational pull of the supermassive black hole at the center of the galaxy provides force to trigger the formation of new stars. But many a times galaxies that should be pumping out stars turn dormant.
Galactic warming has lasting consequences
Scientists used the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey to look at a distant galaxy called Akira that is nearly dormant. Cheung said Akira is a fine example of a red geyser galaxy. Akira was pulling away gas from its companion galaxy Tetsuo to fuel its supermassive black hole winds. Mechanical energy from the winds was enough to heat up the ambient gas in Akira, preventing the formation of new stars. Both Akira and Tetsuo are famous Japanese manga characters.
Findings of the study were published in the journal Nature. Just like global warming here on Earth, galactic warming has lasting consequences like rendering galaxies unable to form new stars.