Chance Alignment Masks Second Galaxy Hiding Out Behind Another

What scientists once believed to be one galaxy is in fact two, new data reveals.

According to observations gathered by the National Science Foundation's Karl. G. Jansky Very Large Array (VLA), a previously unidentified galaxy has been hiding out behind one known as UGC 10288, disguising itself as a massive jet springing forth from the closer of the two.

UGC 10288 is located 100 million light years away. A spiral, it appears as a thin line from Earth. Lying directly behind it and some 7 billion light years from us, is the newly discovered galaxy, seen in blue. The jets seen in the picture and captured using the VLA originate from this galaxy.

According to the researchers behind the new discovery, while earlier radio images made the pair of galaxies appear as one fuzzy blob, radio data from the VLA helped to reveal key distinguishing details.

"We can use the radio waves from the background galaxy, coming through the nearer one, as a way to measure the properties of the nearer galaxy," said Judith Irwin, of Queen's University, Canada, lead author of a recent paper on the findings published in the Astronomical Journal.

Infrared observations made by NASA's Spitzer Space Telescope and Wide-field Infrared Survey Explorer (WISE), appearing in yellow and orange, respectively, also helped to differentiate between the two. Spitzer, for example, helped to confirm an arc-like formation reaching 11,000 light years into space above the disk.

Irwin was aided by an international team of scientists, which included astronomers from North America, India and Europe, all of whom are members of the "Continuum Halos in Nearby Galaxies -- an EVLA Survey" (CHANG-ES) consortium.