New data from NASA / ESA Hubble Space Telescope provides further evidence of tidal disruption in the Galaxy NGC 1052-DF4. This result explains previous discoveries that this galaxy is missing most of its dark matter. By studying the light and globular cluster distribution of galaxies, astronomers have concluded that the gravitational forces of the neighboring galaxy NGC 1035 have stripped the black matter from NGC 1052-DF4 and are now tearing the galaxy apart. This image, made up of images that form part of Digitized Sky Survey 2, shows the sky around NGC 1052-DF4. Credit: ESA / Hubble, NASA, Digitized Sky Survey 2; Acknowledgment: David D. Martin
Using an international team of researchers in 2018 NASA/ ESA Hubble Space Telescope And many other observations uncovered, for the first time, a galaxy in our cosmic neighborhood that is missing most of its dark matter. This discovery of the Galaxy NGC 1052-DF2 came as a surprise to astronomers, as they realized that dark matter is a major component in current models of galaxy formation and evolution. In fact, without the presence of dark matter, there would be a lack of gravitational pull in the primordial gas and the beginning of the formation of new galaxies. A year later, another galaxy that missed a dark object was found, NGC 1052-DF4, which sparked intense discussions among astronomers about the nature of these objects.
Now, new Hubble data has been used to explain the reason behind the missing dark object in NGC 1052-DF4, which is 45 million light years away. Miria Montes of the University of New South Wales in Australia led an international team of astronomers to study the galaxy with the help of deep optical imaging. They discovered that the missing dark matter could be explained by the effects of tidal disruption. The gravitational forces of the neighboring giant Galaxy NGC 1035 are tearing apart NGC 1052-DF4. During this process, the dark matter is removed, while the stars experience the effects of interaction with another galaxy at a later stage.
Until now, removing dark matter in this way has been hidden from astronomers, as it can only be observed using extremely deep ND images that can reveal extremely dizzy characteristics. “We used Hubble in two ways to find out if NGC 1052-DF4 was experiencing an interaction,” Montes explained. “This includes the study of the galaxy’s distribution of light and galactic clusters.”
This image represents the region around the Galaxy NGC 1052-DF4, taken by the IAC 80 Telescope at the Tenerife Observatory in Tenerife, Spain. This figure highlights major galaxies in the field of view, including NGC 1052-DF4 (center of image) and its neighbor NGC 1035 (center left). Credit: M. Montes et al.
Thanks to Hubble’s high resolution, astronomers were able to identify the galaxy’s globular cluster population. The 10.4-meter Gran Telescopio Canaria (GTC) telescope and the IAC 80 telescope were used in the Canary Islands of Spain to supplement Hubble’s observations through further study of the data.
“It’s not enough to just spend a lot of time inspecting the budget, but the data needs to be treated carefully,” explained Raul Infante-Szanz, a member of the team at the Instituto de Stroffsica de Caneria in Spain. “So it was important for us to use not just one telescope / instrument, but several (ground- and space-based) to carry out this research. From Hubble’s high resolution, we can identify global clusters, and then from GTC photometry we obtain physical properties. “
Globular clusters form in episodes of intense star formation that shape galaxies. Their compact size and luminosity make them easily observable, and so they can better detect the properties of their host galaxy. Thus, by studying and characterizing the spatial distribution of clusters in NGC 1052-DF4, astronomers can develop insights into the current state of the galaxy. The configuration of these clusters suggests that they are being “stripped” from their host galaxy, and this supports the conclusion that tides are being disrupted.
By studying the galaxy’s light, astronomers have also found evidence of tidal tails, which form material moving away from NGC 1052-DF4. This further supports the conclusion that this is a disruption event. Additional analysis has revealed that the central parts of the galaxy remain untouched and only 7% of the galaxy’s stars are hosted in these tidal tails. This means that the dark matter, which is less concentrated than the stars, was previously and preferably stripped from the galaxy, and is now beginning to be stripped of the outer stellar component as well.
“This result is a good indicator that, when the dark matter of the galaxy evaporated from the system, the stars are now subject to a disruption system,” explained Ignacio Trujillo, a member of Spain’s Instituto de Astrofísica de Caneria. “Over time, NGC 1052-DF4 could be alerted by the vast system surrounding NGC 1035, at least some of their stars will be floating freely in deep space.”
The search for evidence to support the mechanism of tidal collapse, as the revelation for the galaxy’s missing dark matter has not only solved the astronomical riddle, but also brought a sigh of relief to astronomers. Without it, scientists would have to improve our understanding of the laws of gravity.
“These findings reconcile existing knowledge of how constellations form and evolve with a highly favorable cosmological model,” Montes added.
