What is Zone of Avoidance?
[[File:Milky Way infrared.jpg|thumb|333px|The Milky Way hides galaxies behind it from our view]] The '''Zone of Avoidance''' (ZOA) is the area of the night sky that is obscured by our own [[galaxy]], the [[Milky Way]]. [[Dust]] and [[star]]s in the plane of the Milky Way (the [[galactic plane]]) block our view of about 20% of the sky at [[wikt:visible|visible]] [[wavelength]]s. As a result, optical galaxy catalogues are usually very incomplete close to the galactic plane. ==Modern developments== In more recent years, many projects have attempted to bridge the gap in our knowledge caused by the Zone of Avoidance. However, the effects of the Zone drops at longer wavelengths, such as the [[infrared]], and the Milky Way is effectively [[transparency|transparent]] at [[radio]] wavelengths. Surveys in the infrared have given us a more complete picture of the extragalactic sky. Indeed, two very large nearby galaxies, [[Maffei 1]] and [[Maffei 2]], were discovered in the Zone of Avoidance by [[Paolo Maffei]] by their infrared emission in 1968. Even so, about 10% of the sky remains difficult to survey because extragalactic objects (for example, distant galaxies) can be confused with stars in the Milky Way. Projects to survey the Zone of Avoidance at radio wavelengths have detected many galaxies that could not be detected in the infrared. Examples of galaxies detected from their HI emission include [[Dwingeloo 1]] and [[Dwingeloo 2]]. Important superclusters of galaxies lying hidden or partly hidden by ZOA are The [[Great Attractor]] and the [[Norma Cluster]]. ==References== {{reflist}} *{{cite journal | title = The Universe behind the Milky Way | url = https://archive.org/details/arxiv-astro-ph0005501 | journal = The Astronomy and Astrophysics Review | date = May 24, 2000 | volume = 10 | issue = 3 | pages = 211–261 | arxiv = astro-ph/0005501 |doi = 10.1007/s001590000011 | s2cid = 14760994 | last1 = Kraan-Korteweg | first1 = Ren&#x000E9;e C. | last2 = Lahav | first2 = Ofer | bibcode = 200