Spark
Loading...

Merger Features: Tidal Tails, Bridges, and Interaction Evidence

A tidal tail is a thin, elongated region of stars and interstellar gas that extends into space from a galaxy. Tidal tails occur as a result of galactic tide forces between interacting galaxies. Examples of galaxies with tidal tails include the Tadpole Galaxy and the Mice Galaxies. Tidal forces can eject a significant amount of a galaxy's gas into the tail; within the Antennae Galaxies, for example, nearly half of the observed gaseous matter is found within the tail structures. The phenomena now referred to as tidal tails were first studied extensively by Fritz Zwicky in 1953.

Figures (5)

The Tadpole Galaxy, image taken by the Hubble Space Telescope's ACS.
NGC 3921 is an interacting pair of disc galaxies in the late stages of its merger.[3]
ESO 239-2, an interacting pair of galaxies located 550 million light-years in the constellation of Grus. These galaxies are currently in the last stages of merging which the end result would be an elliptical galaxy.[4]
SDSSCGB 10389, a trio of galaxies merging into a single object[15]
Example of computer simulation of Milky Way and Andromeda collision[16]

Key Points

  • Tidal tails are a common outcome of gravitational interactions between disk galaxies.
  • The majority of starburst galaxies are in the midst of a merger or close encounter with another galaxy.
  • At these redshifts, the 100 micrometer infrared emission is observed at sub-millimeter wavelengths, making this wavelength range favorable for detecting distant ULIRGs.

Terms

Tap a term for a plain-language explanation.

Sources & licensing(4)