Zone of Avoidance
Zone of Avoidance or ZOA for short (in German for "Zone of Avoidance") is a zone in the sky where galaxies are only weakly visible in the optical spectrum or not at all. This zone forms around the galactic equator of the Milky Way . Although the Zone of Avoidance received little attention for a long time, it has been a separate field of research in astronomy since the 1990s . To understand the local universe, it is necessary to know which galaxies are in the vicinity of our Milky Way are located. The cause of the Zone of Avoidance is due to the dust that is inside the Milky Way.
The first thing Proctor referred to in 1878 was a "Zone of few Nebulae" in the General Catalog of Nebulae . Carl Charlier next drew attention to this zone in 1922 when he was studying the data in the New General Catalog . Harlow Shapley was the first to attempt to define the zone in 1961. Shapley found that in the Lick Survey and Harvad Survey there is a zone with fewer than 5 galaxies per square degree , while elsewhere there is 54 galaxies per square degree. During this period, established the term Zone of Avoidance, as astronomers avoided this zone (Engl. Avoid ) because there was insufficient data in this area. In the 1980s, the Uppsala General Catalog , the ESO Uppsala Catalog and the Morphological Catalog of Galaxies , with a few adjustments, a new sky-spanning catalog emerged.
Individual evidence
- ^ A b Renée C. Kraan-Korteweg: The Universe behind the Milky Way . In: The Astronomy and Astrophysics Review . May 24, 2000. arxiv : astro-ph / 0005501 . bibcode : 2000A & ARv..10..211K . doi : 10.1007 / s001590000011 .