Polar Ring Galaxy NGC 660’s a Cosmic Anomaly

A single odd galaxy in a group of around a dozen or so extremely rare, bizarre island universes 

This new Hubble image shows a peculiar galaxy known as NGC 660, located around 45 million light-years away from us. 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. Unfortunately, NGC 660’s polar ring cannot be seen in this image, but has plenty of other features that make it of interest to astronomers – its central bulge is strangely off-kilter and, perhaps more intriguingly, it is thought to harbour exceptionally large amounts of dark matter. In addition, in late 2012 astronomers observed a massive outburst emanating from NGC 660 that was around ten times as bright as a supernova explosion. This burst was thought to be caused by a massive jet shooting out of the supermassive black hole at the centre of the galaxy.
The polar ring of NGC 660 isn’t visible in this Hubble Space Telescope image, but its central bulge looks strangely tilted. Astronomers are more interested in large amounts of invisible dark matter they think could be hidden within it. Studying the formation of its polar ring during galactic interactions and mergers has provided knowledge and understanding of the shape of dark matter halos around galaxies. 

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.  

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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

A large, elliptical galaxy about 300 million light years from Earth.
Astronomers studying dark matter halos observe galaxies like NGC 4555 because it hasn’t interacted much with other galaxies, which makes it easier to dark matter they started with. Chandra has shown this galaxy is embedded in a cloud of 10-million-degree Celcius gas (left) with a diameter of 40,000 light-years, more than twice that of NGC 4445. (left). A dark matter halo ten times the combined mass of the stars in the galaxy (right) and 300 times the mass of the gas cloud would be required to gravitationally hold it. is difficult to determine how much dark matter they originally possessed. Chandra’s observations of NGC 4555 confirms that an isolated, elliptical galaxy can possess a dark matter halo of its own.

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. 

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Polar Ring Galaxy NGC 660 Credit: AstronomyTrek

 

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

Discover NASA

Learn more about galaxies types here

Read about the unique stellar object called the Red Rectangle.

Fly on the icy blue wings of the Hen 2-437.

Read about the recent observation of gravitational waves by LIGO.

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