What we thought was an ordinary spiral galaxy not far from the Milky Way has revealed a hidden surprise.
About 56 million light-years away, NGC 4632 is surrounded by a giant ring of gas that surrounds the galaxy at a highly oblique angle to the galaxy. galaxy plane. Why didn’t I notice it until now? It is invisible in most of the electromagnetic spectrum and only appears when you stare at the sky with a radio telescope.
This discovery may place NGC 4632 in a class of extremely rare galaxies known as . polar ring galaxy – but it also suggests that these galaxies may not be as rare as we think. If anything, NGC 4632 may mean we’ve been looking at them the wrong way.
“This discovery suggests that 1 to 3 percent of nearby galaxies may have gaseous polar rings, which is much more than optical telescopes suggest. Polar rings Galaxies may be more common than previously thought.” says astrophysicist Nathan Degg. from Queen’s University, Canada.
“Although this is not the first time astronomers have observed a polar ring galaxy, NGC 4632 is the first observed with ASKAP, and we may see more galaxies in the future.”
A polar ring galaxy is exactly what its name suggests. A galaxy with a ring of material such as dust, gas, or stars that orbits around or near the galactic pole. That is, perpendicular to the galactic plane.
They usually have glowing rings slanted like a torus and look quite spectacular. von braun space station.
I don’t know how they got that way, but Two current strong candidates.
The first is that matter moves along the cosmic web through intergalactic space, eventually reaching orbit around a galaxy and forming part of it.
A second, more commonly accepted explanation is that the ring is composed of material gravitationally swallowed from another galaxy that interacted closely with the polar ring galaxy.
Interestingly, it tends to be galactic. lenticular and oval A type with a polar ring. These are fuzzy, unstructured galaxies without the distinct spiral arms seen in galaxies like the Milky Way.
![](https://www.sciencealert.com/images/2023/09/ngc-4632.jpg)
Optical observation reveals a surrounding polar ring Approximately 0.5% A view of a nearby lenticular galaxy. However, there is more to the universe than our limited human eyes can see.
Still, Degu and an international team of astronomers didn’t necessarily expect there to be a hidden polar ring around spiral galaxy NGC 4632.
It appeared in data collected by the wide-field ASKAP L-band legacy all-sky blind survey (wallaby) was conducted using the Australian Square Kilometer Array Pathfinder, a powerful radio telescope array located in the Western Australian desert. WALLABY’s goal is to study hundreds of thousands of galaxies in the southern sky and map their gas distribution.
“NGC 4632 is one of two polar ring galaxies identified from the 600 galaxies mapped in the first small-scale WALLABY survey.” Astronomer Berber Kolibalski says: He holds a PhD from the Australian Commonwealth Scientific and Industrial Research Organization (CSIRO).
“Over 200,000 hydrogen-rich galaxies are expected to be revealed using ASKAP in the coming years, including many more rare galaxies like these galaxies with polar rings. This includes galaxies.”
![](https://www.sciencealert.com/images/2023/09/NGC-4650A.jpg)
NGC 4632 doesn’t immediately tell us how polar galaxies form their rings. But it, along with the second polar spiral galaxy the team discovered, NGC6156 – suggests that there may be a large population out there that we have yet to discover.
It may also suggest that the formation mechanism of polar spiral galaxies is different from that of previously confirmed polar galaxies.
The research team hopes that further observations will shed more light on these mysterious objects. This should reveal whether the type of ring (gaseous or star-filled) is related to the structure of the host galaxy. Let’s also take a closer look at NGC 4632 and NGC 6156.
“Better observations and more sophisticated models for both galaxies will allow us to constrain the parameters of the ring’s progenitor (if it actually formed by merger or approach). ” researchers write.
“Understanding whether these are due to interactions or gas accretion will provide constraints on galaxy formation and evolution.”
This study Royal Astronomical Society Monthly Notices.