November 15, 2013
Astronomers Find That What Was Once Thought To Be One Galaxy Is Actually Two
Alan McStravick for redOrbit.com - Your Universe Online
My fifth grade teacher, Elizabeth Titterton, was responsible for teaching me the order of the planets in our solar system. A simple pneumonic ingrained in me an immutable truth that I carry to this day. "My Very Excellent Mother Just Served Us Nesselrode Pie." Of course, the ‘P’, representing Pluto, has been recast as simply a ‘minor’ planet, somehow stripping me of the concept of absolute truth for the rest of my life.
And the universe and her unending mystery didn’t stop there. We learned this week that a single galaxy, observed for some time, is actually two separate galaxies that have fooled the smartest among us. In what we believed was a single galaxy, astronomers observed what looked like a colossal jet shooting away into the heavens. It turns out, though, this was simply an illusion. Data collected from the Karl G. Jansky Very Large Array (VLA) reveals two distinct galaxies lying one behind the other.
This discovery was made combining radio data from the VLA (shown in blue) with infrared observations from NASAs Spitzer Space Telescope and Wide-field Infrared Survey Explorer (WISE), exhibiting colors of yellow and orange. The visible data in the image shows local starlight in hues of purplish-blue and heated gases in rose.
The closer of the two galaxies, known as UGC 10288, is a mere 100 million light years away from Earth. While it has a spiral shape, we have only observed its thin edge from our vantage point on this planet. The farther galaxy is actually 7 billion light-years away from our planet. In the captured image, one can see two giant jets expelled from this galaxy. One of these jets appears just above the plane of UGC 10288 and was the cause for this astronomical confusion.
Not to fault earlier scientists, previous radio images of the two distinct galaxies appeared as a single fuzzy blob. It required the VLA to unmask the cosmic deception, giving scientists the opportunity to learn facts that were previously unobtainable, regarding the nearer galaxy.
"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, appearing online on November 15, in the Astronomical Journal.
The VLA couldn’t have discovered this new twist on its own. Additional observations from both Spitzer and WISE instructed the observation team of new structures above and below the plane of UGC 10288s disk. Spitzer was responsible for confirming an arc-like feature which rose more than 11,000 light-years above the disk. This was evident in the radio observations.
The team was comprised of an international consortium of astronomers from North America, India and Europe. These scientists belong to a consortium called the “Continuum Halos in Nearby Galaxies – an EVLA Survey,” also known as CHANG-ES.