A single odd galaxy in a group of around a dozen or so extremely rare, bizarre island universes
Space news (galactic interactions: rare galaxy types; polar ring galaxies) – 45 million light-years from Earth, swimming in the cosmic seas of the constellation Pisces –
One of the most enigmatic objects discovered during the human journey to the beginning of space and time, polar ring galaxies are a cosmic anomaly. Containing a belt of gas and stars orbiting its center that it tore from another galaxy during a collision around one billion years ago, polar ring galaxies are composed of two distinct systems. One of the rarest and oddest galaxy types classified, astronomers study the formation mechanisms of polar ring galaxies in order to try to grasp more knowledge and understanding of the evolution of galaxies.
NGC 660 is classified as a “polar ring galaxy”, meaning that it has a belt of gas and stars around its centre that it ripped from a near neighbour during a clash about one billion years ago. The first polar ring galaxy was observed in 1978 and only around a dozen more have been discovered since then, making them something of a cosmic rarity. Credit: Gemini North Telescope
Studying dark matter halos
The study of the formation history of unique polar-ring spiral galaxy NGC 660 has been even more useful in the detection and shape of the galaxy’s otherwise unseen dark matter halo. The only island universe of this kind detected, so far, a team of astronomers at the Paris Observatory has been studying the formation of its polar ring during interactions and mergers between galaxies. In order to gain insight into the shape of dark matter halos around the thousands of galaxies viewed during our journey.
The disk of NGC 660 has a flat rotation curve and a rising polar ring astronomers find intriguing and rather puzzling. Scientists are studying its flatness and haven’t reached a conclusion, but they have determined it has a massive polar ring. It does raise a few difficulties in measuring the polar ring and disk velocities since they can’t be measured at the same radius. But astronomers have observed this in previous dark matter studies using polar ring galaxies.
NGC 660’s also of interest to astronomers because late in 2012 they observed a massive burst emanating from this polar ring galaxy. An energetic outburst estimated to be nearly ten times as bright as a supernova event, they attribute to a massive jet shooting out of the supermassive black hole believed to reside at its core. This island universe’s a one-of-a-kind galaxy astronomers study looking for clues to its unique structure and formation history. A uniqueness that both intrigues and puzzles their inquisitive natures’.
Learn about the things astronomers have determined about polar ring galaxies here.
Learn more about dark matter.
Take the space voyage of the ESA here.
Learn more about galaxies types here.