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In astronomy, the intracluster medium (or ICM) is the superheated gas present at the center of a galaxy cluster. This plasma is heated to temperatures of between roughly 10 and 100 million Kelvin and consists mainly of ionised hydrogen and helium, containing most of the baryonic material in the cluster. The ICM strongly emits X-ray radiation. For other uses, see Astronomy (disambiguation). ...
Galaxy groups and clusters are super-structures in the spread of galaxies of the cosmos. ...
For other uses, see Plasma. ...
For other uses, see Kelvin (disambiguation). ...
// An ion is an atom, group of atoms, or subatomic particle with a net electric charge. ...
This article is about the chemistry of hydrogen. ...
General Name, symbol, number helium, He, 2 Chemical series noble gases Group, period, block 18, 1, s Appearance colorless Standard atomic weight 4. ...
In particle physics, the baryons are a family of subatomic particles including the proton and the neutron (collectively called Greek barys, meaning heavy, as they are heavier than the other main groups of particles. ...
In the NATO phonetic alphabet, X-ray represents the letter X. An X-ray picture (radiograph) taken by Röntgen An X-ray is a form of electromagnetic radiation with a wavelength approximately in the range of 5 pm to 10 nanometers (corresponding to frequencies in the range 30 PHz...
Comparison of the Chandra image of the X-ray emission from the intracluster medium in the core of the Abell 2199 galaxy cluster against the optical emission of the galaxies (from the Digitized Sky Survey). Image File history File links Size of this preview: 800 × 543 pixelsFull resolution‎ (1,206 × 819 pixels, file size: 101 KB, MIME type: image/jpeg) File historyClick on a date/time to view the file as it appeared at that time. ...
Image File history File links Size of this preview: 800 × 543 pixelsFull resolution‎ (1,206 × 819 pixels, file size: 101 KB, MIME type: image/jpeg) File historyClick on a date/time to view the file as it appeared at that time. ...
The Chandra X-ray Observatory is a satellite launched on STS-93 by NASA on July 23, 1999. ...
In the NATO phonetic alphabet, X-ray represents the letter X. An X-ray picture (radiograph) taken by Röntgen An X-ray is a form of electromagnetic radiation with a wavelength approximately in the range of 5 pm to 10 nanometers (corresponding to frequencies in the range 30 PHz...
The Digitized Sky Survey (DSS) is a digital version of several photographic atlases of the night sky, and an ongoing project to produce more digital versions of photographic astronomical datasets. ...
Heating
The ICM is heated to high temperatures by the gravitational energy released by the formation of the cluster from smaller structures. Kinetic energy gained from the gravitational field is converted to thermal energy by shocks. The high temperature ensures that the elements present in the ICM are ionised. Light elements in the ICM have all the electrons removed from their nuclei. Energy of two or more masses (or other forms of energy-momentum) gravitationally interacting with each other. ...
The cars of a roller coaster reach their maximum kinetic energy when at the bottom of their path. ...
A gravitational field is a model used within physics to explain how gravity exists in the universe. ...
In thermal physics, thermal energy is the energy portion of a system that increases with its temperature. ...
Introduction The shock wave is one of several different ways in which a gas in a supersonic flow can be compressed. ...
// An ion is an atom, group of atoms, or subatomic particle with a net electric charge. ...
Properties The electron (also called negatron, commonly represented as e−) is a subatomic particle. ...
Plural: nuclei In chemistry and physics, the nucleus (atomic nucleus) is the collection of protons and neutrons in the center of an atom that carries the bulk of the atoms mass and positive charge. ...
Composition The ICM is composed primarily of ordinary baryons (mainly ionised hydrogen and helium). This plasma is enriched with heavy elements, such as iron. The amount of heavy elements relative to hydrogen (known as metallicity in astronomy) is roughly a third of the value in the sun. Most of the baryons in the cluster (80-95%) reside in the ICM, rather than in the luminous matter, such as galaxies and stars. However, most of the mass in a galaxy cluster consists of dark matter. Combinations of three u, d or s-quarks with a total spin of 3/2 form the so-called baryon decuplet. ...
For other uses, see Iron (disambiguation). ...
The globular cluster M80. ...
Sol redirects here. ...
For other uses, see Dark matter (disambiguation). ...
Although the ICM on the whole contains the bulk of a cluster's baryons, it is not very dense, with typical values of 10-3 particles per cubic centimeter. The mean free path of the particles is roughly 1016 m, or about one lightyear. For sound waves in an enclosure, the mean free path is the average distance the wave travels between reflections off of the enclosures walls. ...
The strong gravitational field of clusters means that they can retain even elements created in high-energy supernovae. Studying the composition of the ICM at varying redshift (which results in looking at different points back in time) can therefore give a record of element production in the universe if they are typical[1]. For other uses, see Supernova (disambiguation). ...
This article is about the physical phenomenon. ...
Observing As the ICM is so hot, it mostly emits X-ray radiation by the bremsstrahlung process and X-ray emission lines from the heavy elements. These X-rays can be observed using an X-ray telescope. Depending on the telescope, maps of the ICM can be made (the X-ray emission is proportional to the density of the ICM squared), and X-ray spectra can be obtained. The brightness of the X-rays tells us about the density of the gas. The spectra allow temperature and metallicity of the ICM to be measured. In the NATO phonetic alphabet, X-ray represents the letter X. An X-ray picture (radiograph) taken by Röntgen An X-ray is a form of electromagnetic radiation with a wavelength approximately in the range of 5 pm to 10 nanometers (corresponding to frequencies in the range 30 PHz...
(help· info), (from the German bremsen, to brake and Strahlung, radiation, thus, braking radiation), is electromagnetic radiation produced by the acceleration of a charged particle, such as an electron, when deflected by another charged particle, such as an atomic nucleus. ...
A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range, compared with the nearby frequencies. ...
ROSAT image of X-ray fluorescence of, and occultation of the X-ray background by, the Moon. ...
In most modern usages of the word spectrum, there is a unifying theme of between extremes at either end. ...
The density of the ICM rises towards the centre of the cluster with a strong peak. In addition, the temperature of the ICM typically drops to 1/2 or 1/3 of the outer value in the central regions. The metallicity rises from the outer region towards the centre. In some clusters (e.g. the Centaurus cluster) the metallicity of the gas can rise above that of the sun. The Centaurus Cluster (A3526) is a cluster of hundreds of galaxies, located in approximately 170 millions of light years away in the Centaurus constellation. ...
Cooling flow As the ICM in the core of many galaxy clusters is dense, it emits a lot of X-ray radiation (the emission is proportional to the density-squared). In the absence of heating, the ICM should be cooling. As it cools, hotter gas will flow in to replace it. This is known as a cooling flow. The cooling flow problem is the lack of evidence of cooling of the ICM. A cooling flow[1] occurs according to the theory that the intracluster medium (ICM) in the centres of galaxy clusters should be rapidly cooling at the rate of tens to thousands of solar masses per year. ...
See also Galaxy groups and clusters are super-structures in the spread of galaxies of the cosmos. ...
Intergalactic space is the physical space between galaxies. ...
References - ^ Loewenstein, Michael. Chemical Composition of the Intracluster Medium, Carnegie Observatories Centennial Symposia, p.422, 2004.
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