CO-0.40-0.22 is a high velocity compact

gas cloud An interstellar cloud is generally an accumulation of gas, plasma, and dust in our and other galaxies. Put differently, an interstellar cloud is a denser-than-average region of the interstellar medium, the matter and radiation that exists in t ...

near the centre of the Milky Way. It is 200 light years away from the centre in the central molecular zone. The cloud is in the shape of

ellipse In mathematics, an ellipse is a plane curve surrounding two focus (geometry), focal points, such that for all points on the curve, the sum of the two distances to the focal points is a constant. It generalizes a circle, which is the special ty ...

. The differences in the velocity, termed velocity dispersion, of the gas is unusually high at 100 km/s. The velocity dispersion was once thought to be due to an intermediate-mass black hole (IMBH) with a mass of about 100,000 solar masses. However, observations with the Atacama Large Millimeter/submillimeter Array suggested the evidence for a cloud-cloud collision. Subsequent theoretical studies of the gas cloud and nearby IMBH candidates have re-opened the possibility, though no observational evidence for existence of an IMBH has been reported. The molecular cloud has a mass of 4,000

solar mass The solar mass () is a standard unit of mass in astronomy, equal to approximately . It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxies and black holes. It is approximately equal to the mass ...

es. It is located at −0.40°, −0.22° galactic longitude and latitude. The cloud is 0.2° away from Sgr C to the galactic southeast. The gas is moving away from Earth at speeds ranging from 20 to 120 km/s. The spectral lines of carbon monoxide reveal that the gas is dense, and warm and fairly opaque. The gas cloud includes carbon monoxide and

hydrogen cyanide Hydrogen cyanide, sometimes called prussic acid, is a chemical compound with the formula HCN and structure . It is a colorless, extremely poisonous, and flammable liquid that boils slightly above room temperature, at . HCN is produced on an ...

molecules. Other molecules detected via microwave spectroscopy include

cyanoacetylene Cyanoacetylene is an organic compound with formula or . It is the simplest cyanopolyyne. Cyanoacetylene has been detected by spectroscopic methods in interstellar clouds, in the coma of comet Hale–Bopp and in the atmosphere of Saturn's m ...

cyclopropenylidene Cyclopropenylidene, or ''c''-C3H2, is a partially aromatic molecule belonging to a highly reactive class of organic molecules known as carbenes. On Earth, cyclopropenylidene is only seen in the laboratory due to its reactivity. However, cyclopr ...

methanol Methanol (also called methyl alcohol and wood spirit, amongst other names) is an organic chemical and the simplest aliphatic alcohol, with the formula C H3 O H (a methyl group linked to a hydroxyl group, often abbreviated as MeOH). It is a ...

, silicon monoxide, sulfur monoxide,

carbon monosulfide Carbon monosulfide is a chemical compound with the formula CS. This diatomic molecule is the sulfur analogue of carbon monoxide, and is unstable as a solid or a liquid, but it has been observed as a gas both in the laboratory and in the interstel ...

Thioformaldehyde Thioformaldehyde is the organosulfur compound with the formula CH2S. This compound is very rarely observed because it oligomerizes to 1,3,5-trithiane, which is a stable colorless compound with the same empirical formula. Despite its instability ...

, Hydrogen isocyanide,

Formamide Formamide is an amide derived from formic acid. It is a colorless liquid which is miscible with water and has an ammonia-like odor. It is chemical feedstock for the manufacture of sulfa drugs and other pharmaceuticals, herbicides and pesticide ...

, and ions H₂N⁺ and HCO⁺. The name followed the precedent set by CO-0.02-0.02, which is another high velocity compact cloud in the central molecular zone. Another example of this naming convention is CO–0.30–0.07.

References

{{Reflist Molecular clouds Sagittarius (constellation) Intermediate-mass black holes