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The categories of dark matter are set with respect to the size of a protogalaxy (an object that later evolves into a dwarf galaxy): dark matter particles are classified as cold, warm, or hot if their FSL is much smaller (cold), similar to (warm), or much larger (hot) than a protogalaxy.
GN-z11 is a high-redshift galaxy found in the constellation Ursa Major.It is among the farthest known galaxies from Earth ever discovered. [5] [6] The 2015 discovery was published in a 2016 paper headed by Pascal Oesch and Gabriel Brammer (Cosmic Dawn Center).
The listed objects currently include most objects in the asteroid belt and moons of the giant planets in this size range, but many newly discovered objects in the outer Solar System are missing, such as those included in the following reference. [58] Asteroid spectral types are mostly Tholen, but some might be SMASS.
As of 21 May 2015, WISE-J224607.57-052635.0-20150521 is the most luminous galaxy discovered and releases 10,000 times more energy than the Milky Way galaxy, although smaller. Nearly 100 percent of the light escaping from this dusty galaxy is Infrared radiation.
In March 2019, astronomers reported that the virial mass of the Milky Way Galaxy is 1.54 trillion solar masses within a radius of about 39.5 kpc (130,000 ly), over twice as much as was determined in earlier studies, suggesting that about 90% of the mass of the galaxy is dark matter.
The galaxy has an uncertain morphology. Based on the "total" aperture at the K-band, Phoenix A has an angular diameter of 16.20 arcseconds, corresponding to a large isophotal diameter of 206.1 kiloparsecs (672,200 light-years), making it one of the largest known galaxies discovered from Earth. [3] Phoenix A also contains vast amounts of hot gas.
Abell 2744, nicknamed Pandora's Cluster, is a giant galaxy cluster resulting from the simultaneous pile-up of at least four separate, smaller galaxy clusters that took place over a span of 350 million years, and is located approximately 4 billion light years from Earth. [1] The galaxies in the cluster make up less than five percent of its mass. [1]
A dark or "ultra diffuse" galaxy is an extremely-low-luminosity galaxy. It may be the same size as the Milky Way, but have a visible star count only one percent of the Milky Way's. Multiple mechanisms for producing this type of galaxy have been proposed, and it is possible that different dark galaxies formed by different means. [102]