The spectacular barred spiral galaxy NGC 6872, long ranked among the biggest observed stellar systems, spans more than 522,000 light-years, making it more than five times the size of our Milky Way galaxy, they said.
They made the determination by analyzing archival data from NASA's Galaxy Evolution Explorer mission, now operated by the California Institute of Technology in Pasadena, Calif.
"Without GALEX's ability to detect the ultraviolet light of the youngest, hottest stars, we would never have recognized the full extent of this intriguing system," lead scientist Rafael Eufrasio, a research assistant at NASA's Goddard Space Flight Center in Greenbelt, Md., told a meeting of the American Astronomical Society meeting in Long Beach, Calif.
The researchers studied the galaxy using archival data from the European Southern Observatory's Very Large Telescope, the Two Micron All Sky Survey, and NASA's Spitzer Space Telescope, as well as data from GALEX.
NGC 6872 is located 212 million light-years from Earth in the southern constellation of Pavo.