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Survey of Andromeda’s Satellite Galaxies

Telescope image with infographic overlays. At top left the text reads, Hubble Space Telescope, Survey of Andromeda's Satellite galaxies. A large field of galaxies take up the left three-quarters. This portion shows hundreds scattered across the black background of space. Most are tiny white dots. Thirty-six tiny galaxies are circled in yellow. Four have labels. From top to bottom, left to right: NGC 185, NGC 147, NGC 205 (M110), NGC 221 (M32). NGC 221 appears slightly lower than a larger, angled oblong galaxy, which is labeled Andromeda Galaxy (M31). Along the right is a column separated into four boxes, each a zoomed in portrait of the labeled galaxies. From top to bottom: NGC 185 looks like a dim blue haze that takes up most of the frame; NGC 147 like a small, very dim oval, with scattered dots nearby; NGC 221 is large and bright white, and takes up most of the box; NGC 205 is not quite as large as NGC 221, and is pinker, with larger dots throughout the frame.

This is a wide-angle view of the distribution of known satellite galaxies orbiting the large Andromeda galaxy (M31), located 2.5 million light-years away. The Hubble Space Telescope was used to study the entire population of 36 mini-galaxies circled in yellow. Andromeda is the bright spindle-shaped object at image center. All the dwarf galaxies seem to be confined to a plane, all orbiting in the same direction. The wide view is from ground-based photography. Hubble's optical stability, clarity, and efficiency made this ambitious survey possible. Hubble close up snapshots of four dwarf galaxies are on image right. The most prominent dwarf galaxy is M32 (NGC 221), a compact ellipsoidal galaxy that might be the remnant core of a larger galaxy that collided with Andromeda a few billion years ago.

About the Object

  • R.A. Position
    R.A. PositionRight ascension – analogous to longitude – is one component of an object's position.
    00:42:44
  • Dec. Position
    Dec. PositionDeclination – analogous to latitude – is one component of an object's position.
    +41:16:09
  • Constellation
    ConstellationOne of 88 recognized regions of the celestial sphere in which the object appears.
    Andromeda
  • Distance
    DistanceThe 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.
    2.537 million light-years

About the Data

  • Data Description
    Data 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 pullout image of NGC 185 was created from Hubble data from proposal 15336 (A. Ferguson).

  • Instrument
    InstrumentThe science instrument used to produce the data.
    NGC 185: WFC3/UVIS
  • Exposure Dates
    Exposure DatesThe date(s) that the telescope made its observations and the total exposure time.
    NGC 185: September 2019
  • Filters
    FiltersThe camera filters that were used in the science observations.
    F606W, F814W
  • Object Name
    Object NameA name or catalog number that astronomers use to identify an astronomical object.
    Andromeda Galaxy and surroundings
  • Object Description
    Object DescriptionThe type of astronomical object.
    Spiral Galaxy
  • Release Date
    February 27, 2025
  • Science Release
    NASA’s Hubble Provides Bird’s-Eye View of Andromeda Galaxy’s Ecosystem
    Read the release
  • Credit
    Image: NASA, ESA, DSS2, Alessandro Savino (UC Berkeley), Joseph DePasquale (STScI), Akira Fujii

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Telescope image with infographic overlays. At top left the text reads, Hubble Space Telescope, Survey of Andromeda's Satellite galaxies. A large field of galaxies take up the left three-quarters. This portion shows hundreds scattered across the black background of space. Most are tiny white dots. Thirty-six tiny galaxies are circled in yellow. Four have labels. From top to bottom, left to right: NGC 185, NGC 147, NGC 205 (M110), NGC 221 (M32). NGC 221 appears slightly lower than a larger, angled oblong galaxy, which is labeled Andromeda Galaxy (M31). Along the right is a column separated into four boxes, each a zoomed in portrait of the labeled galaxies. From top to bottom: NGC 185 looks like a dim blue haze that takes up most of the frame; NGC 147 like a small, very dim oval, with scattered dots nearby; NGC 221 is large and bright white, and takes up most of the box; NGC 205 is not quite as large as NGC 221, and is pinker, with larger dots throughout the frame.
Color Info
Color InfoA brief description of the methods used to convert telescope data into the color image being presented.

These images were acquired by the WFC3 instrument on the Hubble Space Telescope. The color results from assigning different hues (colors) to a monochromatic (grayscale) image. In this case, the assigned colors are: Cyan: F606W, Orange: F814W.

Related Images & Videos

A wide-angle view of the distribution of 36 satellite galaxies orbiting the large Andromeda galaxy, which resembles bees swarming around a hive.

The Distribution of Satellite Galaxies around M31

This animation begins with a view of the neighboring Andromeda galaxy. We zoom through a scattering of foreground stars and enter the inky blackness of intergalactic space. We cross 2.5 million light-years to reach the Andromeda system, consisting of 36 dwarf satellite galaxies...

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Details

Last Updated
Mar 18, 2025
Contact
Media

Claire Andreoli
NASA’s Goddard Space Flight Center
Greenbelt, Maryland
claire.andreoli@nasa.gov

Image Credit

NASA, ESA, DSS2, Alessandro Savino (UC Berkeley), Joseph DePasquale (STScI), Akira Fujii

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