JUN 22, 2021 10:07 AM PDT

An Unusual Galaxy Without Dark Matter

WRITTEN BY: Carmen Leitch

Even though we still cannot detect dark matter, many researchers are confident that exists. It seems to act as a kind of glue that binds galaxies together and exerts a powerful influence on the conventional matter that we can detect easily. It's also been suggested that dark matter is an essential part of galaxies. But new research has identified a galaxy that does not bear any of the standard hallmarks of dark matter. This ultra-diffuse galaxy (UDG) is called NGC1052-DF2 (DF2), and scientists believe that the galaxy, which is at a distance of about 22.1 +/-1.2 megaparsecs, does not contain dark matter.

NGC1052-DF2 / Credit: NASA, ESA, Z. Shen and P. van Dokkum (Yale University), and S. Danieli (Institute for Advanced Study)

"Determining an accurate distance to DF2 has been key in supporting our earlier results," said study co-leader Shany Danieli, a NASA Hubble Fellow at the Institute for Advanced Study. "The new measurement reported in this study has crucial implications for estimating the physical properties of the galaxy, thus confirming its lack of dark matter."

This work is based on data collected during  40 orbits of NASA's Hubble Space Telescope. The findings have been reported in Astrophysical Journal Letters.

"We went out on a limb with our initial Hubble observations of this galaxy in 2018," noted study co-leader Pieter van Dokkum of Yale University. The team's 2018 research used  "surface brightness fluctuations" to measure distance.  "I think people were right to question it because it's such an unusual result. It would be nice if there were a simple explanation, like a wrong distance. But I think it's more fun and more interesting if it actually is a weird galaxy."

In 2019, the team measured the distance between D2 and a neighbor, UDG NGC1052-DF4 (DF4), which also suggested that there wasn't any dark matter. This study has confirmed that research and has refined their initial measurements; the galaxies are probably a bit further apart than the scientists first thought, which actually strengthens the case that there's no dark matter there.

The motion of stars in DF2 and DF4 can be explained solely by stellar mass, which indicates that there is no unseen force - like dark matter - acting on the bodies. Finding galaxies that lack dark matter might help us learn more about it, and how galaxies grow.

DF2 and DF4 are both about the size of the Milky Way but they only contain about one percent of the mass the Milky Way holds. They are ultra-diffuse, and they also have a large amount of especially luminous globular clusters.

"There's a saying that extraordinary claims require extraordinary evidence, and the new distance measurement strongly supports our previous finding that DF2 is missing dark matter," said study co-leader Zili Shen of Yale University. "Now it's time to move beyond the distance debate and focus on how such galaxies came to exist."

Sources: AAAS/Eurekalert! via Institute for Advanced Study, Astrophysical Journal Letters

About the Author
Bachelor's (BA/BS/Other)
Experienced research scientist and technical expert with authorships on over 30 peer-reviewed publications, traveler to over 70 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
SEP 09, 2022
Space & Astronomy
Perseverance Likes Green Sand with Red Sand
Perseverance Likes Green Sand with Red Sand
In an array of studies, one published in Science Advances and two published in Science, a large international team of re ...
OCT 16, 2022
Space & Astronomy
NASA's Chandra X-ray Telescope Provides a New Perspective for James Webb Space Telescopes Images
NASA's Chandra X-ray Telescope Provides a New Perspective for James Webb Space Telescopes Images
In the summer of 2022, NASA’s James Webb Space Telescope (JWST) released its very first images to the public. Now, ...
NOV 16, 2022
Space & Astronomy
Where Did the Planets Go?
Where Did the Planets Go?
A new study published in the Astrophysical Journal Letters presents a solution to some mysterious patterns that have sho ...
NOV 23, 2022
Space & Astronomy
JWST Images a Star in the Midst of Formation
JWST Images a Star in the Midst of Formation
This image can easily be mistaken for a planetary nebula, but it is actually an image of a young star in the midst of fo ...
DEC 20, 2022
Space & Astronomy
Astronomers Have Found the Best Evidence of "Water Worlds" To Date
Astronomers Have Found the Best Evidence of "Water Worlds" To Date
A recent paper published in Nature Astronomy presents a detailed study of the planetary system Kepler-138 and has found ...
JAN 09, 2023
Space & Astronomy
Saturn's Walnut-Shaped Iapetus | Solar System Moons
Saturn's Walnut-Shaped Iapetus | Solar System Moons
We recently explored Saturn's moon, Pan, and its unique, food-like features that emanate from gathering dust via Saturn' ...
Loading Comments...