“A small, mysterious galaxy 44 million light-years away is finally yielding up its secrets. Revealed last year to have a shockingly low amount of dark matter, the galaxy NGC 1052-DF4 posed a significant challenge to our models of galaxy formation.
Those models yet live another day. According to new research, NGC 1052-DF4 is indeed lacking in dark matter – but only because another nearby galaxy nicked it.
The dark matter isn’t there because it’s already been removed, We found that the gravitational pull from the nearby massive galaxy NGC1035 is removing its stars – and dark matter.
Using the IAC80 Telescope, the Gran Telescopio Canarias, and the Hubble Space Telescope, they detected stars being pulled out of DF4, consistent with an interaction with the much larger spiral galaxy NGC 1035. This process, whereby a larger body gravitationally “disrupts” a smaller one, is known as tidal disruption.”
References:
The scientific Research:
The Galaxy “Missing Dark Matter” NGC 1052-DF4 is Undergoing Tidal Disruption
Mireia Montes et al.
Published 2020 November 26
The American Astronomical Society.
The Astrophysical Journal, Volume 904, Number 2
Abstract:
The existence of long-lived galaxies lacking dark matter represents a challenge to our understanding of how galaxies form. Here, we present evidence that explains the lack of dark matter in one such galaxy: NGC 1052-DF4. Deep optical imaging of the system has detected tidal tails in this object caused by its interaction with its neighboring galaxy NGC 1035. As stars are more centrally concentrated than dark matter, tidal stripping will remove a significant percentage of dark matter before affecting the stars of the galaxy. Only 7% of the stellar mass of the galaxy is in the tidal tails, suggesting that the stars of NGC 1052-DF4 are only now starting to be affected by the interaction, while the percentage of remaining dark matter is ≤ 1% . This naturally explains the low content of dark matter inferred for this galaxy and reconciles these types of galaxies with our current models of galaxy formation.
https://iopscience.iop.org/article/10.3847/1538-4357/abc340
https://www.sciencealert.com/we-now-know-why-this-tiny-galaxy-has-almost-no-dark-matter
The draft version of the research