Spiral galaxies, of which our own galaxy, the Milky Way, is an example, are one of many types of galaxies that exist in the universe, being first described by famed astronomer Edwin Hubble. Being quite common in our own neck of the woods, spiral galaxies have become some of the most recognizable galaxies, and in the latest find by astronomers, the largest known spiral galaxy has been discovered.
An international team consisting of researchers from the Catholic University of America, NASA's Goddard Space Flight Center, the University of Sao Paulo, Brazil, and the European Southern Observatory in Chile discovered the new spiral galaxy, the NGC 6872, using data from the Galaxy Evolution Explorer (Galex) satellite, according to the researchers, purely by chance.
Previous research had established that the NGC 6872 was among some of the largest spiral galaxies observed, but a “freak” cosmic occurrence, in which a lens-shaped galaxy, the IC 4970, crashed into the spiral galaxy, has now made the NGC 6872 the largest known spiral galaxy.
Detailing their findings at the 221st American Astronomical Society annual meeting, which was recently held in California, the researchers said that from their observations they have determined that the NGC 6872 is so massive that it could potentially hold five of our own Milky Ways within it. Located in the Parvo constellation, some 212 million light years away from Earth, the NGC 6872 has a flurry of star forming activity going on within it, with the researchers discovering young stars forming in the galaxy’s spiral arms and much older ones in the galaxy’s central disc with the lenticular galaxy, the IC 4970, adding even more stars to the spiral galaxy.
Speaking about the find, one of the researchers, Rafael Eufrasio, said, "I was not looking for the largest spiral - it just came as a gift," adding, "It's been known to be among the largest for two decades, but it's much larger than we thought. The galaxy that collided with the [central disc of NGC 6872] splashed stars all over the place - 500,000 light-years away."
Mr. Eufrasio added that the discovery of the NGC 6782 not only meant that the largest observed spiral galaxy had been discovered, but also increased the number of known “galaxy smash ups,” as with the NGC 6782 and the IC 4970, "it shows the evolution of galaxies in the larger context of the Universe - how the large galaxies we had before were accreted from small clumps in the early Universe. We're just seeing one example of two interacting galaxies but in the past that happened much more often - that's how the big [spiral galaxy] discs we have were probably formed. Putting that in a larger context, it's a very cool system.”