Aero-Terms are designed to be a daily reminder of the terms,
names, acronyms and explanations of the unique language that
populates the aviation world. Aerospace, sport aviation, fixed
wing, helo, you name it... it's all fair game.
Aero-Terms should serve as a quick but intriguing reminder of
the terms you may use every day, or an introduction to an aspects
of the Aero-World you may not yet be familiar with. ANN also
encourages readers to go beyond the FMI link, and further research
any intriguing terms.
A luminous giant elliptical galaxy typically found near the
center of a cluster of galaxies. D galaxies are similar in
appearance to ordinary ellipticals, but their brightness declines
more slowly with distance from the center, making them look as if
they have diffuse halos (the "D" stands for "diffuse".) A CD galaxy
is even bigger and brighter and is found centrally located in a
rich cluster of galaxies. CD galaxies are believed to have grown so
large through galaxy mergers. Indeed, several CD galaxies are
observed to have multiple galactic nuclei, as if they are still in
the process of cannibalizing smaller systems.