Kiso 5639 is just a tadpole when it comes to galaxies, but it’s a real firecracker in a picture unveiled by the Hubble Space Telescope’s science team just in time for the Fourth of July.
Today’s image emphasizes the galaxy’s blazing head and its long, star-studded tail in shades of red, purple and blue that’d be well-suited for a fireworks display. The colors represent the different wavelengths that were picked up by Hubble’s Wide Field Camera 3 and UVIS imager during viewing opportunities in February and July of 2015. (A version of the picture released by the European Space Agency’s Hubble team isn’t quite as colorful.)
KIso 5639, which lies 82 million light-years away in the northern constellation Ursa Major, is an elongated type of galaxy known as a tadpole. The tadpole’s bright head marks a frenzy of starbirth, thought to be sparked by intergalactic gas that’s raining down on one end of the galaxy as it drifts through space. About 10 percent of all galaxies in the early universe are tadpoles, but few such galaxies have been seen nearby.
“I think Kiso 5639 is a beautiful, up-close example of what must have been common long ago,” Vassar College astronomer Debra Elmegreen said in today’s news release. “The current thinking is that galaxies in the early universe grow from accreting gas from the surrounding neighborhood. It’s a stage that galaxies, including our Milky Way, must go through as they are growing up.”
Elmegreen and other members of an international research team chose Kiso 5639 (also known as LEDA 36252) out of 10 nearby tadpole galaxies for a Hubble close-up. In a paper accepted for publication by the Astrophysical Journal, the team reports that the clusters of stars in the galaxy’s head have an average age of less than 1 million years, and masses that are up to six times as heavy as the stars in the rest of the galaxy.
The astronomers suggest that the fireworks started up when Kiso 5639 encountered a huge filament of intergalactic gas, and that other parts of the galaxy may light up like the skies on the Fourth of July as they spin through the same filament.
In addition to Debra Elmegreen, the authors of “Hubble Space Telescope Observations of Accretion-Induced Star Formation in the Tadpole Galaxy Kiso 5639” include Bruce Elmegreen, Jorge Sanchez Almeida, Casiana Muñoz-Tuñón, Mercedes Filho, Jairo Mendez-Abreu, John Gallagher, Marc Rafelski and Daniel Ceverino.