                        Astronomy Picture of the Day

    Discover the cosmos! Each day a different image or photograph of our
      fascinating universe is featured, along with a brief explanation
                    written by a professional astronomer.

                              2024 September 27

                    Stellar Streams in the Local Universe
                 Image Credit: David Martinez Delgado et al.

   Explanation: The twenty galaxies arrayed in these panels are part of an
   ambitious astronomical survey of tidal stellar streams. Each panel
   presents a composite view; a deep, inverted image taken from publicly
   available imaging surveys of a field that surrounds a nearby massive
   galaxy image. The inverted images reveal faint cosmic structures, star
   streams hundreds of thousands of light-years across, that result from
   the gravitational disruption and eventual merger of satellite galaxies
   in the local universe. Such surveys of mergers and gravitational tidal
   interactions between massive galaxies and their dwarf satellites are
   crucial guides for current models of galaxy formation and cosmology. Of
   course, the detection of stellar streams in the neighboring Andromeda
   Galaxy and our own Milky Way also offers spectacular evidence for
   ongoing satellite galaxy disruption within our more local galaxy group.

                    Tomorrow's picture: eclipse at sunset
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Phillip Newman Specific rights apply.
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                           NASA Science Activation
                             & Michigan Tech. U.

