After billions of years wandering in the proverbial wilderness, two galaxies, Pisces A and B, are returning to cosmic civilization.
Recently, the Hubble Space Telescope caught a glimpse of the two galaxies, having made their way into a much denser collection of galaxies — a hub of cosmic activity astronomers are calling the “big city.”
The wilderness the two galaxies wandered in from is called the Local Void. The lonely region spans some 150 million light-years.
Their return to civilization — which actually began about 100 million years ago — triggered a burst of creativity. A plethora of young blue stars suggests the two galaxies are birthing new stars at an accelerated clip. Researchers suspect the uptick in star formation was fueled by big city’s denser supply of intergalactic gas.
“These Hubble images may be snapshots of what present-day dwarf galaxies may have been like at earlier epochs,” lead researcher Erik Tollerud, an astronomer at the Space Telescope Science Institute in Baltimore, said in a news release. “Studying these and other similar galaxies can provide further clues to dwarf galaxy formation and evolution.”
Though it is difficult to predict, researchers say the two galaxies’ star formation could soon slow. If the dwarf galaxies get pulled into orbit around a larger galaxy, their gas supply is likely to be cut off.
“The galaxies could even probably stop forming stars altogether, because they will stop getting new gas to make stars,” Tollerud said. “So they will use up their existing gas. But it’s hard to tell right now exactly when that would happen, so it’s a reasonable guess that the star formation will ramp up at least for a while.”
The story of the two loner galaxies was detailed in a new paper published in the Astrophysical Journal.