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NGC 1052-DF2
Hubble Views ‘Ghostly’ Galaxy Lacking Dark Matter
This large, fuzzy-looking galaxy is so diffuse that astronomers call it a “see-through” galaxy because they can clearly see distant galaxies behind it.
The ghostly object, catalogued as NGC 1052-DF2, doesn’t have a noticeable central region, or even spiral arms and a disk, typical features of a spiral galaxy. But it doesn’t look like an elliptical galaxy, either. Even its globular clusters are oddballs: they are twice as large as typical stellar groupings seen in other galaxies.
All of these oddities pale in comparison to the weirdest aspect of this galaxy: NGC 1052-DF2 is missing most, if not all, of its dark matter. An invisible substance that makes up the bulk of our universe, dark matter is the underlying scaffolding upon which galaxies are built. It’s the glue that holds the visible matter in galaxies — stars and gas — together.
The galaxy contains at most 1/400th the amount of dark matter that astronomers had expected. But how it formed is a complete mystery.
The galactic oddball is as large as our Milky Way, but it had escaped attention because it contains only 1/200th the number of stars as our galaxy. Given the object’s large size and faint appearance, astronomers classify NGC 1052-DF2 as an ultra-diffuse galaxy.
Based on the colors of its globular clusters, NGC 1052-DF2 is about 10 billion years old. It resides about 65 million light-years away.
The image was taken Nov. 16, 2016, by Hubble’s Advanced Camera for Surveys.
About the Object
- R.A. PositionR.A. PositionRight ascension – analogous to longitude – is one component of an object's position.02:41:46.728
- Dec. PositionDec. PositionDeclination – analogous to latitude – is one component of an object's position.-08:24:09.871
- ConstellationConstellationOne of 88 recognized regions of the celestial sphere in which the object appears.Cetus
- DistanceDistanceThe physical distance from Earth to the astronomical object. Distances within our solar system are usually measured in Astronomical Units (AU). Distances between stars are usually measured in light-years. Interstellar distances can also be measured in parsecs.The galaxy is 62 million light-years away from Earth.
- DimensionsDimensionsThe physical size of the object or the apparent angle it subtends on the sky.Image is 2.5 arcmin across (about 45,000 light-years)
About the Data
- Data DescriptionData DescriptionProposal: A description of the observations, their scientific justification, and the links to the data available in the science archive.
Science Team: The astronomers who planned the observations and analyzed the data. "PI" refers to the Principal Investigator.The HST observations include those from program 14644 (P. van Dokkum) - InstrumentInstrumentThe science instrument used to produce the data.ACS/WFC
- Exposure DatesExposure DatesThe date(s) that the telescope made its observations and the total exposure time.16 Nov 2016
- FiltersFiltersThe camera filters that were used in the science observations.F606W, F814W
- Object NameObject NameA name or catalog number that astronomers use to identify an astronomical object.NGC 1052-DF2
- Object DescriptionObject DescriptionThe type of astronomical object.Ultra Diffuse Galaxy
- Release DateMarch 28, 2018
- Science ReleaseDark Matter Goes Missing in Oddball Galaxy
- Credit
These images are a composite of separate exposures acquired by the ACS/WFC instrument on the Hubble Space Telescope. Several filters were used to sample narrow wavelength ranges. The color results from assigning different hues (colors) to each monochromatic (grayscale) image associated with an individual filter. In this case, the assigned colors are: Blue: F606W Red: F814W
Related Images & Videos
Hubble Views a Galaxy Lacking Dark Matter
NASA's Hubble Space Telescope took an image of a bizarre, ghostly looking galaxy called NGC 1052-DF2 that astronomers calculate to have little to no dark matter. This is the first galaxy astronomers have discovered to be so lacking in dark matter, which is thought to comprise...
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Claire Andreoli
NASA’s Goddard Space Flight Center
Greenbelt, Maryland
claire.andreoli@nasa.gov
