Dark matter has always been a perennial mystery to scientists. A new study has unraveled the enigma behind galaxy NGC1052-DF2.
The DF2 or the "galaxy without dark matter" is about the same size as Milky Way but appears as an ultra-diffuse one with fewer stars (100 to 1,000 times lesser) compared to Earth's galaxy.
Apparently, the DF2 is closer to Earth than what was previously thought by astronomers. When the galaxy was discovered last year, scientists estimated its distance at about 65 million light-years away in the constellation Cetus.
Researchers from the Instituto de Astrofísica de Canarias in Tenerife, Spain now claim that the previous assumptions and estimates were anomalous. New calculations and more accurate estimates reveal that the galaxy would be around 42 million light years away.
This significant information places the distance of DF2 as normal and within "the observed trends traced by galaxies with similar characteristics."
The Galaxy Has Dark Matter After All
"With this revised distance, the galaxy appears to be a rather ordinary low surface brightness galaxy with plenty of room for dark matter," the researchers wrote on their study published in the journal Monthly Notices of the Royal Astronomical Society.
When astronomers came across the galaxy last year, they were perplexed by its supposed lack or absence of dark matter. Pieter van Dokkum, an astronomy professor at Yale University whose team published a study about the DF2, said: "finding a galaxy without dark matter is unexpected because this invisible, mysterious substance is the most dominant aspect of any galaxy."
However, IAC scientists led by Ignacio Trujillo used five various methods that include photometry from the Hubble Space Telescope and the Gemini Observatory to recalculate the distance to DF2. Outcome of their observations manifests the same conclusion: the DF2 is closer than previously indicated in studies.
"The results of this work show the fundamental importance of the correct measurement of extragalactic distances. It has always been one of the most challenging tasks in astrophysics: how to measure the distances to objects which are very far away and which we cannot touch," the authors said in a statement.
A more relevant discovery based on the new distant analysis shows that galaxy's total mass of is just half of the mass estimated previously and the mass of its stars is only about a quarter of previously estimated mass. This suggests that a large part of the total mass must be made up of dark matter.
Why Dark Matter Matters?
Dark matter is considered fundamental in the formation of stars. It would be nearly impossible to decipher and study galaxies that are devoid of dark matter in the context of current theories of galaxy formation.
It is said that "invisible dark matter connects galaxies in the universe" but very little is known about it. According to NASA, the universe is composed of roughly 68 percent dark energy while the other 27 percent is dark matter.
The European Organization for Nuclear Research or CERN recently announced the development of an instrument that will probe for dark matter particles. At present, the most powerful particle machine is the Large Hadron Collider in Geneva, Switzerland
