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Interacting Galaxies Group Arp 194

Interacting Galaxies Group Arp 194

To commemorate the Hubble Space Telescope's 19 years of historic, trailblazing science, the orbiting telescope has photographed a peculiar system of galaxies known as Arp 194. This interacting group contains several galaxies, along with a "cosmic fountain" of stars, gas, and dust that stretches over 100,000 light-years.

The northern (upper) component of Arp 194 appears as a haphazard collection of dusty spiral arms, bright blue star-forming regions, and at least two galaxy nuclei that appear to be connected and in the early stages of merging. A third, relatively normal, spiral galaxy appears off to the right. The southern (lower) component of the galaxy group contains a single large spiral galaxy with its own blue star-forming regions.

However, the most striking feature of this galaxy troupe is the impressive blue stream of material extending from the northern component. This "fountain" contains complexes of super star clusters, each one of which may contain dozens of individual young star clusters. The blue color is produced by the hot, massive stars which dominate the light in each cluster. Overall, the "fountain" contains many millions of stars.

These young star clusters probably formed as a result of the interactions between the galaxies in the northern component of Arp 194. The compression of gas involved in galaxy interactions can enhance the star-formation rate and give rise to brilliant bursts of star formation in merging systems.

Hubble's resolution shows clearly that the stream of material lies in front of the southern component of Arp 194, as evidenced by the dust that is silhouetted around the star-cluster complexes. It is therefore not entirely clear whether the southern component actually interacts with the northern pair.

The details of the interactions among the multiple galaxies that make up Arp 194 are complex. The shapes of all the galaxies involved appear to have been distorted, possibly by their gravitational interactions with one another.

Arp 194, located in the constellation Ursa Major, resides approximately 600 million light-years away from Earth. It contains some of the many interacting and merging galaxies known in our relatively nearby universe. These observations were taken in January of 2009 with the Wide Field Planetary Camera 2. Images taken through blue, green, and red filters were combined to form this picturesque image of galaxy interaction.

About the Object

  • R.A. Position
    R.A. PositionRight ascension – analogous to longitude – is one component of an object's position.
    11h 57m 55.29s
  • Dec. Position
    Dec. PositionDeclination – analogous to latitude – is one component of an object's position.
    36° 23' 19.99"
  • Constellation
    ConstellationOne of 88 recognized regions of the celestial sphere in which the object appears.
    Ursa Major
  • 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.
    600 million light-years or 184 megaparsecs
  • Dimensions
    DimensionsThe physical size of the object or the apparent angle it subtends on the sky.
    This image is 76 arcseconds (220,000 light-years or 68,000 parsecs) wide.

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 Hubble images were created from HST data from proposal 11956: K. Noll, Z. Levay, M. Mutchler, L. Frattare, M. Livio, W. Januszewski, C. Christian, F. Hamilton, and H. Bond (Hubble Heritage Team/STScI).
  • Instrument
    InstrumentThe science instrument used to produce the data.
    HST>WFPC2
  • Exposure Dates
    Exposure DatesThe date(s) that the telescope made its observations and the total exposure time.
    January 14-19, 2009, Exposure Time: 4.7 hours
  • Filters
    FiltersThe camera filters that were used in the science observations.
    F450W (B), F606W (V), and F814W (I)
  • Object Name
    Object NameA name or catalog number that astronomers use to identify an astronomical object.
    Arp 194
  • Object Description
    Object DescriptionThe type of astronomical object.
    Interacting galaxy system
  • Release Date
    April 21, 2009
  • Science Release
    Hubble Celebrates Its 19th Anniversary with a “Fountain of Youth”
  • Credit
    NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

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Interacting Galaxies Group Arp 194
Color Info
Color InfoA brief description of the methods used to convert telescope data into the color image being presented.

The image is a composite of separate exposures made by the WFPC2 instrument on the Hubble Space Telescope. Three filters were used to sample broad wavelength ranges. The color results from assigning different hues (colors) to each monochromatic image. In this case, the assigned colors are: Blue: F450W (B) Green: F606W (V) Red: F814W (I)

Compass and Scale
Compass and ScaleAn astronomical image with a scale that shows how large an object is on the sky, a compass that shows how the object is oriented on the sky, and the filters with which the image was made.

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Details

Last Updated
Mar 28, 2025
Contact
Media

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