The Fornax Galaxy Cluster, which contains distorted dwarf galaxies in its collection. Image Credit: ESO
The Milky Way Galaxy has a coterie of dwarf galaxies around it,. Remarkably, current studies reveal that at least one of the dwarf galaxies near ours, an ancient one called Tucana II, has an astoundingly massive dark matter halo.
Finding Perturbed Dwarf Galaxies
In the so-called “Standard Model” of cosmology, shells or halos of dark matter safeguard galaxies from the gravitational influence of nearby galactic neighbors. When astronomers at the University of Bonn and Saint Andrews in Scotland looked in the neighboring Fornax Cluster, which lies some 62 million light-years away from us, they saw something odd. It contains a variety of dwarf galaxies with distorted, worried shapes. This is odd, specifically if they must be surrounded by dark matter halos.
Ask astronomers about dark matter and one of the important things they discuss is that this invisible, strange “things” penetrates deep space. In particular, it exists in halos surrounding most galaxies. The mass of the halo puts in a strong gravitational impact on the galaxy itself, in addition to on others in the community. Thats practically the standard view of dark matter and its impact on galaxies. There are issues with the idea of those halos. Apparently, some oddly shaped dwarf galaxies exist that appear like they have no halos. How could this be? Do they represent an observationally caused difficulty to the prevailing concepts about dark matter halos?
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The distorted shapes of the dwarf galaxies seen by the team indicate an issue with our understanding of dark matter. The research group points out that its hard to explain these irritated, disrupted shapes of the dwarf galaxies in Fornax if theyre surrounded by dark matter.
Apparently, some strangely shaped dwarf galaxies exist that look like they have no halos. The Milky Way Galaxy has a coterie of dwarf galaxies around it,. Remarkably, recent research studies reveal that at least one of the dwarf galaxies near ours, an ancient one called Tucana II, has an astoundingly massive dark matter halo.
There, dwarf galaxies could be “disturbed” by gravitational tides from neighboring larger ones in the cluster. Tides take place when gravity from one body pulls differently on different parts of another body.
The distorted shapes of the dwarf galaxies seen by the team suggest an issue with our understanding of dark matter. “Such perturbations in the Fornax dwarfs are not expected according to the Standard Model,” said Pavel Kroupa, Professor at the University of Bonn and Charles University in Prague. “This is because, according to that design, the dark matter halos of these dwarfs ought to partially shield them from tides raised by the cluster.”
Discussing Distorted Dwarf Galaxies
One is the internal attributes of the dwarf galaxy. As a rule, galaxies with big sizes however not lots of stars might be quickly disrupted by strong gravitational tides. The same is true for galaxies closer to the core of the cluster.
The group members compared what they saw in the cluster with observations made by the VLT Survey Telescope at the European Southern Observatory. Asencio mentioned that what they found appears to indicate issues with the Standard Model. “The comparison revealed that, if one wishes to explain the observations in the standard design,” she stated, “the Fornax overshadows should currently be ruined by gravity from the cluster center even when the tides it raises on a dwarf are sixty-four times weaker than the dwarfs own self-gravity.”
Not only is this counter-intuitive, she stated, it also opposes previous studies. The group also discovered that the force needed to disrupt a dwarf galaxy has to do with the very same as its self-gravity.
What Does This Mean for the Standard Model?
The research team points out that its tough to discuss these irritated, disturbed shapes of the dwarf galaxies in Fornax if theyre surrounded by dark matter. That suggests that there are no dark matter halos around those galaxies.
Certainly, if what the astronomers discovered is verified, then the Standard Model requires some tweaking. And, there is at least one alternative explanation for the odd galaxy shapes. Its called the MOND design (brief for Modified Newtonian Dynamics). It suggests that Newtons law of universal gravitation need to be modified to account for the observed homes of galaxies. It might be used to explain why misshapen galaxies look the method they do.
According to Hongsheng Zhao, a member of the research group from the University of Saint Andrews, finding disturbed overshadows without dark matter halos is a major obstacle to the existing view. It specifies that galaxies have halos. It appears not all of them do, he points out. “Our outcomes have significant implications for basic physics,” he stated. “We expect to discover more disturbed dwarfs in other clusters, a forecast which other teams must confirm”.
For more details
No trace of dark matter halosThe circulation and morphologies of Fornax Cluster dwarf galaxies suggest they lack dark matterModified Newtonian Dynamics
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