![]() where's all the dark matter? Into the darkĪstronomers have postulated that polar ring galaxies might be created when a larger galaxy eats a smaller one in just the right way. With a bounty of curiosities to delve into, ASKAP then provides an opportunity to help answer some of the Universe's most burning questions. In total, WALLABY hopes to spot upwards of 200,000 galaxies. ![]() "The two polar ring galaxies are just the beginning of a huge project," Professor Koribalski said. The find highlights the promise of ASKAP and its capabilities. If the discovery of the polar rings is confirmed, it also suggests these types of galaxies are much more common than previously thought. "We do need to confirm these fully as being polar," Deg noted. Again, their models seemed to suggest this could be a polar ring, though with less certainty. In this case, the researchers had to look at the speed of the gas moving around the galaxy. It lies about 150 million light-years away and its ring is much less obvious. A polar ring seemed to be the best explanation for the mass of gas surrounding it. ![]() The hydrogen gas from the inner galaxy has also been removed, to bring out the ring shape.įurther computer modelling helped the research team simulate the dynamics of NGC 4632, exploring how the gas moves around. Of the two galaxies, its hydrogen ring is the most obvious.īecause the hydrogen gas is detectable only at radio wavelengths that can't be seen by the human eye, images of NGC 4632, like the one at the top of this article, have been digitally colourised in white. NGC 4632 was first spotted by the survey in 2022 and originally described as a spiral galaxy situated in the Virgo constellation, lying about 56 million light-years away. The WALLABY survey presented an opportunity to study the dynamics of the hydrogen gas surrounding NGC 4632 and NGC 6156 in more detail. "With ASKAP, we see both where the gas is on the sky, but also how fast the gas is moving towards or away from us," Deg said. The hydrogen signal provides a way to map the structure of gas inside and outside of galaxies and can offer clues about how that gas moves. The two potential polar ring galaxies were spotted in the first data release from WALLABY, an all-sky survey that uses ASKAP's 36 antennas to look for a specific type of hydrogen across the universe. They may even help provide a way to understand dark matter, an elusive force that permeates the cosmos. If they are confirmed as polar ring galaxies, they present a way to understand how these curious and rare galaxies form and evolve. "Some spiral galaxies with large warped disks can look like polar rings," said Bärbel Koribalski, an astronomer at CSIRO and co-author on the new study. Though the evidence suggests these may be polar rings, the researchers are quick to point out the stunning structures could have other explanations. Estimates from previous research suggest they make up about only 0.1 percent of galaxies.įinding two in a sample of 600 galaxies was a total surprise, Deg said. One of the most famous examples, NGC 4650a, was imaged by the Hubble telescope in 1999.īut they are tough to find. Polar ring galaxies typically appear as a central disk of stars, gas and dust enclosed by a second, perpendicular ring - like a frisbee zipping through a hula hoop. The potential discovery of two polar ring galaxies, led by Deg, was published in the journal Monthly Notices of the Royal Astronomical Society. "These are some of the most spectacular looking galaxies that we see," Deg said. Searching through a catalogue of more than 600 galaxies, Nathan Deg stumbled upon two that seemed perfectly gift-wrapped.ĭr Deg, an astrophysicist from Queen's University in Ontario, Canada, was analysing data from the Australian Square Kilometre Array Pathfinder (ASKAP) telescope array in Western Australia, when he was struck by the characteristics of galaxies NGC 4632 and NGC 6156.Ī ribbon of thick hydrogen gas surrounding the galaxies was the first hint he may have found an exceedingly rare and beautiful type of cosmic structure, known as a polar ring galaxy. CSIRO/ASKAP radio telescope, NAOJ/Subaru Telescope Manitoba), Nathan Deg (Queen's University) & WALLABY Survey. A colourised radio telescope image of the central disk of NGC 4632 surrounded by a thick band of hydrogen gas (white).
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