When a worldwide group of astronomers observed the ultra-diffuse galaxy AGC 114905, they found no proof of Dark Matter at all. They then made a graph that revealed the distance of the gas from the center of the galaxy (x-axis) and the rotational speed of the gas (y-axis), which is a standard way of exposing the impact of dark matter. For beginners, AGC 114905 might have been removed of its dark matter through tidal interaction with neighboring big galaxies. With modified Newtonian characteristics, an alternative theory to cold dark matter, we can not reproduce the motions of the gas within the galaxy.”.
In 2018, a team of Canadian and american astronomers led by Pieter van Dokkum (the Sol Goldman Family Professor of Astronomy at Yale) discovered an ultra-diffuse galaxy (NGC1052– DF2) that was likewise bereft of dark matter.
As the team described in a previous research study, the roadway to this discovery began when Pavel Mancera Piña– a Ph.D. trainee with the University of Groningen and ASTRON and the lead author on both papers– and his colleagues observed six galaxies that appeared to have little or no dark matter. These findings contradicted prevailing theories about dark matter, which specifies that all galaxies (especially ultra-diffuse dwarf galaxies) might not exist without dark matter to hold them together.
Piña and his coworkers were instructed to retake their measurements and utilized the Very Large Array ( VLA) in New Mexico to perform an observation project of one galaxy in specific. This was AGC 114905, a gas-rich, ultra-diffuse dwarf galaxy located about 250 million light-years away in the constellation Pisces. This classification refers to the fact that it is a low luminosity galaxy with far fewer stars than galaxies like ours (in spite of being comparable in size).
Throughout this project, the team gathered information on the rotation of gas in AGC 114905 for 40 hours in between July and October 2020. They then made a graph that showed the distance of the gas from the center of the galaxy (x-axis) and the rotational speed of the gas (y-axis), which is a standard method of revealing the influence of dark matter. This graph revealed that the presence of normal matter alone could discuss the motions of the gas in AGC 114905.
As Piña described in a current Royal Astronomical Society news release:
” This is, naturally, what we hoped and believed for because it confirms our previous measurements. And now the issue stays that the theory anticipates that there must be dark matter in AGC 114905, however our observations say there isnt. The difference in between theory and observation is only getting bigger.”
Simulation of dark matter and gas. Credit: Illustris Collaboration (CC BY-SA 4.0).
As Piña and his colleagues show in their study, there are a number of possible explanations for the absence of dark matter. For beginners, AGC 114905 might have been removed of its dark matter through tidal interaction with surrounding big galaxies. They likewise adjusted the specifications of the Lamba-Cold Dark Matter (? CDM) cosmological model and alternate theories to General Relavity to get worths consistent with their observations. But as Piñan explained, none of it worked:.
” But there are none. And in the most reputed galaxy formation structure, the so called cold dark matter design, we would need to present severe specification worths that are far beyond the normal variety. With modified Newtonian characteristics, an alternative theory to cold dark matter, we can not recreate the motions of the gas within the galaxy.”.
Another possibility they considered was that their estimates of the approximated angle at which they were observing the galaxy were off (which would have altered their conclusions substantially). However Tom Oosterloo (a scientist with ASTRON and a co-author on the paper) suggested, that angle would have “to deviate quite from our estimate before there is space for dark matter again.”.
This is not the very first time astronomers observed a galaxy that appeared to have little or no Dark Matter. In 2018, a group of American and Canadian astronomers led by Pieter van Dokkum (the Sol Goldman Family Professor of Astronomy at Yale) found an ultra-diffuse galaxy (NGC1052– DF2) that was likewise bereft of dark matter. The techniques and measurements used by Piña and his coworkers supplied more robust outcomes.
Hubble picture of NGC 1052-DF2, an ultra-diffuse galaxy that appears to have little or no dark matter. Credit: NASA/ESA/P. van Dokkum (Yale University).
If they again find no traces of Dark Matter, it will confirm that galaxies are out there that defy the? This could be excellent news, as it will use new restrictions on Dark Matter and its function in galactic and cosmic advancement.
To paraphrase Isaac Asimov, the most exciting phrase to hear in science is not Eureka, however Thats amusing ….
Additional Reading: RAS, MRAS.
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The research team was led by scientists from the Kapteyn Astronomical Institute at the University of Groningen and the Netherlands Institute for Radio Astronomy (ASTRON). They were signed up with by astronomers and cosmologists from the University of Durham, Valparaiso University, and the University of Illinois. Their research study findings were accepted for publication and will appear in the Monthly Notices of the Royal Astronomical Society.
One of the greatest cosmological secrets dealing with astrophysicists today is Dark Matter. Given that the 1960s, researchers have actually postulated that this unnoticeable mass accounts for many of the matter in the Universe. While there are still numerous unsolved questions about it– i.e., What is it composed of?
Astrophysicists have actually observed that Dark Matter played a vital role in the development of galaxies and is accountable for keeping them gravitationally bound. Nevertheless, when a global team of astronomers observed the ultra-diffuse galaxy AGC 114905, they discovered no evidence of Dark Matter at all. This discovery might force researchers to review their cosmological designs and the way we look at the Universe if these observations are accurate.
