Astronomers discover five rare galaxies 'interacting with each other'

A group of five ‘dwarf’ galaxies that are ‘interacting with each other’ have been discovered by astronomers about 117 million light years away from Earth

Dwarf galaxies contain a few billion stars, whereas standard galaxies have hundreds of billions, giving them low mass and luminosity.

The newly found galaxies are blue, gas-rich and actively forming new stars.

They were given the designations D1 to D5, with D3 and D4 displaying indications of mutual tidal interactions, which implies that their respective gravitational forces are tugging on each other and altering the shapes of the galaxies. 

D3 and D4 have formed ‘tidal tails,’ which are slim, elongated areas consisting of stars and interstellar gas that extend outwards and away from the location where the galaxies are colliding.

It is highly uncommon for dwarf galaxies to appear in groups as studies suggest less than five percent of dwarf galaxies are neighbors with another. 

Thus, there is less an a 0.004 percent chance that a dwarf galaxy would be so close to four others.

Despite those incredibly low odds, ‘We have identified a distinct group of dwarf galaxies, with all five members aligned along a straight line in the celestial plane and three sharing a common rotational direction,’ the researchers wrote in their report.

The discovery of this exceedingly unique group is forcing scientists to question the prevailing model of our universe, but should also help scientists better understand how dwarf galaxies form and evolve. 

The group of dwarf galaxies, designated D1 through D5, is exceedingly rare

A team of researchers led by the Yonsei University in Seoul, South Korea, discovered the dwarf galaxy group by analyzing data from various astronomical surveys that continually scan space looking for new discoveries.

These surveys use telescopes to observe millions of celestial objects in deep space, creating enormous, highly detailed maps of the universe.

The researchers’ analysis revealed the presence of the group of dwarf galaxies, isolated together in deep space.

They estimated the total dynamical mass – or the mass of an object inferred from its movement relative to other objects – of the group to be roughly 60.2 billion times the mass of our sun, the study found. 

Their individual masses vary widely. The largest group member, galaxy D2, has a stellar mass of approximately 275 million solar masses. 

The least massive, D4, has a stellar mass of only 14.7 million solar masses.

For comparison, our galaxy – the Milky Way – has a stellar mass of about 1.5 trillion solar masses, according to NASA.

The researchers published their findings in The Astrophysical Journal Letters on November 19. 

They were designated from D1 to D5, and two of them – D3 and D4 – are showing signs of mutual tidal interactions , which means their respective gravitational forces are pulling on each other and distorting the galaxies’ shapes 

Dwarf galaxies only contain a few billion stars , whereas standard galaxies have hundreds of billions. This is irregular dwarf galaxy NGC 6822 - which is not part of the newly found group

Dwarf galaxies only contain a few billion stars , whereas standard galaxies have hundreds of billions. This is irregular dwarf galaxy NGC 6822 – which is not part of the newly found group

To find five dwarf galaxies grouped together in a near-straight line, with most of them rotating in the same direction, is so unusual that it challenges predictions made by the prevailing model of how the universe formed.

That model, called Lambda cold dark matter (LCDM), suggests that dark matter causes disordered groupings of galaxies.

By that logic, galaxies are not expected to have a preferred alignment. The five dwarf galaxies, however, are aligned in a configuration that is ‘not frequently seen in CDM simulations,’ study lead author Sanjaya Paudel of Yonsei University in South Korea told Space.com.

What’s more, the fact that three of the five galaxies share the same direction of rotation – as shown by DESI observations – suggests that they formed from the same cloud of gas. This further contradicts the LCDM model. 

‘Why do they have the same rotation?’ said Paudel. ‘They must have a connection with each other – that would be a very strong question that cannot be explained by the ΛCDM model.’ 

As of now, this discovery yields more questions than answers. But future studies could soon confirm whether the galaxies’ unlikely configuration is a chance projection or a real physical arrangement, the researchers stated in their report.

Additionally, studying these five dwarf galaxies could help scientists better understand how such objects form and evolve.

Astronomers believe dwarf galaxies were created by gravitational forces in the early stages of the creation of larger galaxies, or as a result of collisions between galaxies that eject streams of material out into space. 

Dwarf galaxies are thought to be important for important in scientists’ understanding of the overall evolution of galaxies, according to the European Space Agency. 

Those that lack a defined shape – known as ‘irregular’ dwarf galaxies – are considered similar to the earliest galaxies that populated the Universe. Thus, studying them offers a glimpse into ancient cosmological history.  

More than 20 known dwarf galaxies orbit the Milky Way. But they are locationally and gravitationally separate from each other, not grouped together. 

Leave a Reply

Your email address will not be published. Required fields are marked *

You May Also Like

Attorney for Hannah Kobayashi criticizes photo sent to sister as part of ‘green card marriage’ investigation

THE lawyer representing the family of missing Hannah Kobayashi has called out…

Attack with firebomb injures two at crowded Australian synagogue

In an early morning incident at a synagogue in Melbourne’s Jewish community,…

Urgent Search for 6 Men in Baltimore Bridge Collapse Ends with Final Victim Found After 43 Days

Plunged into complete darkness due to a power outage, the crew of…

Search is ongoing for shooter in mask who killed insurance company CEO named Brian Thompson

Investigators are going through clues discovered at the location of the deadly…

Parents in Georgia Face Charges for Allowing Teens to Drink at Home and Drive Under the Influence

A teenager and two parents are facing felonies in connection to a…

Authorities Investigating Murder of 5-Year-Old Autistic Boy

An investigation is underway by Oregon authorities into the disappearance and death…

New Clues Emerge in Investigation of UnitedHealthcare CEO’s Murder

Investigators are reportedly working with limited forensic evidence in Wednesday’s shooting of…

Former head girl attempts to claim £4.2m estate and 7-bed home by forging headmistress’ will, loses court case against family

A DISGRACED ex-head girl who forged her headmistress’ will to pocket her…

Disturbing sight: Russian diplomat smiles during UN discussion of mother and 3 daughters killed by Putin’s missiles

This disturbing incident captured a Russian official smirking while hearing about the…

James Dyson criticizes Labour’s Budget as damaging to the UK economy

SIR James Dyson has attacked Labour’s Budget as an “act of self-harm”…

Actor from Outlander allegedly assaulted a woman in a hotel room while she was unconscious, then was confronted by a co-star according to court testimony

During his testimony today, a television actor stated that he had acted…

University-educated parents starve son to death, bury him in garden – Explore their unconventional lifestyle and disturbing beliefs

When Naiyahmi Yasharahyalah was arrested, she was so thin and frail she…