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Hubble’s new data explains the missing dark matter



Hubble's new data explains the missing dark matter

This image shows the sky around the ultra-diffuse galaxies NGC 1052-DF4 and NGC 1052-DF2. It is created from images that are part of Digitazed Sky Survey 2. NGC 1052-DF2 is basically invisible in this image. In 2018, an international team of researchers using the NASA / ESA Hubble Space Telescope and several other observatories discovered for the first time a galaxy in our space neighborhood that lacks most of its dark matter. This discovery of the galaxy NGC 1052-DF2 was a surprise to astronomers, as it was understood that dark matter (DM) is a key ingredient in current models for the formation and evolution of galaxies. In fact, without the presence of DM, the primary gas will not have enough gravitational attraction to begin to collapse and form new galaxies. A year later, another galaxy that leaked dark matter, NGC 1052-DF4, was discovered, further sparking intense debate among astronomers about the nature of these objects. New Hubble data is now being used to explain the cause of the missing dark matter in NGC 1052-DF4, which is 45 million light-years away, providing further evidence of tidal interference. By studying the distribution of light and globular clusters in the galaxy, astronomers have concluded that the gravitational forces of the neighboring galaxy NGC 1035 are taking dark matter from NGC 1052-DF4 and are now tearing the galaxy apart. Credit: ESA / Hubble, NASA, Digitazed Sky Survey 2 Recognition: Davide de Martin

New data from NASA / ESA’s Hubble Space Telescope provide further evidence of tidal destruction in the galaxy NGC 1052-DF4. This result explains a previous discovery that this galaxy lacks most of its dark matter. By studying the distribution of light and globular clusters in the galaxy, astronomers have concluded that the gravitational forces of the neighboring galaxy NGC 1035 are taking dark matter from NGC 1052-DF4 and are now tearing the galaxy apart.


In 2018, an international team of researchers using the NASA / ESA Hubble Space Telescope and several other observatories discovered for the first time a galaxy in our space neighborhood that lacks most of its dark matter. This discovery of the galaxy NGC 1052-DF2 was a surprise to astronomers, as it was understood that dark matter (DM) is a key ingredient in current models for the formation and evolution of galaxies. In fact, without the presence of DM, the primary gas will not have enough gravitational attraction to begin to collapse and form new galaxies. A year later, another galaxy that missed dark matter was discovered, NGC 1052-DF4, which further sparked intense debate among astronomers about the nature of these objects.

New Hubble data is now being used to explain the cause of the missing dark matter in NGC 1052-DF4, which is 45 million light-years away. Mireya Montes of the University of New South Wales in Australia leads an international team of astronomers to study the galaxy using deep optical images. They found that the missing dark matter could be explained by the effects of tidal disturbances. The gravitational forces of the neighboring massive galaxy NGC 1035 rupture NGC 1052-DF4. During this process, dark matter is removed, while the stars feel the effects of interacting with another galaxy at a later stage.

So far, the removal of dark matter in this way remains hidden from astronomers, as it can only be observed with the help of extremely deep images, which can reveal extremely weak features. “We used Hubble in two ways to find that NGC 1052-DF4 was interacting,” Montes explained. “This includes studying the light of the galaxy and the distribution of globular clusters in the galaxy.”

Thanks to Hubble’s high resolution, astronomers can identify the population of the galaxy’s globular clusters. The Gran Telescopio Canarias 10.4-meter telescope and the IAC80 telescope in the Canary Islands, Spain, were also used to supplement Hubble’s observations through further data research.

Hubble's new data explains the missing dark matter

This image represents the region around the galaxy NGC 1052-DF4, made by the IAC80 telescope at the Teide Observatory in Tenerife. The figure highlights major galaxies in the field of view, including NGC 1052-DF4 (center of the image) and its neighbor NGC 1035 (center-left). Credit: M. Montes et al.

“It’s not enough to just spend a lot of time observing the object, but careful handling of the data is vital,” said team member Raul Infante-Sainz of the Canary Institute of Astrophysics in Spain. “So it was important to use not just one telescope / instrument, but several (both terrestrial and space) to conduct this study. With Hubble’s high resolution, we can identify globular clusters, and then use GTC photometry to obtain the physical properties. . “

Spherical clusters are thought to form in episodes of intense star formation that form galaxies. Their compact size and brightness make them easily noticeable, and therefore they are good tracking properties of their host galaxy. Thus, by studying and characterizing the spatial distribution of clusters in NGC 1052-DF4, astronomers can develop an idea of ​​the current state of the galaxy itself. The alignment of these clusters suggests that they have been “removed” from their host galaxy, and this supports the conclusion that a tidal disorder is occurring.

By studying the light of the galaxy, astronomers also found evidence of tidal tails formed by material moving away from NGC1052-DF4 – further supporting the conclusion that this is a destructive event. Further analysis concludes that the central parts of the galaxy remain intact and only ∼ 7% of the galaxy’s stellar mass is in these tidal tails. This means that dark matter, which is less concentrated than the stars, was previously mostly and largely removed from the galaxy, and now the outer stellar component is beginning to separate.

“This result is a good indicator that while the dark matter of the galaxy is evaporating from the system, the stars are only now beginning to suffer from the mechanism of destruction,” explained team member Ignacio Trujillo of the Canary Institute of Astrophysics in Spain. “Over time, NGC1052-DF4 will be cannibalized by the large system around NGC1035, with at least some of their stars floating freely in deep space.”

The discovery of evidence to support the mechanism of the destruction of tides as an explanation for the galaxy’s missing dark matter has not only solved an astronomical mystery, but has also eased astronomers. Without it, scientists will face the need to reconsider our understanding of the laws of gravity.

“This discovery combines existing knowledge about how galaxies form and evolve with the most favorable cosmological model,” Montes added.

These results are published in Astrophysical Journal.


Physicists explain the mysterious deficit of dark matter in the pair of galaxies


More info:
The galaxy “Missing Dark Matter” NGC1052-DF4 undergoes tidal destruction arXiv: 2010.09719 [astro-ph.GA] arxiv.org/abs/2010.09719

Provided by ESA / Hubble Information Center

Quote: Hubble’s new data explains missing dark matter (2020, November 26), retrieved on November 26, 2020 from https://phys.org/news/2020-11-hubble-dark.html

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