Effective gravitational interactions of dark matter axions
... Here we dropped the processes which violate axion number. Because such processes are forbidden due to the conservation of energy and three momenta at the first order in HI as long as axions are non-relativistic. ...
... Here we dropped the processes which violate axion number. Because such processes are forbidden due to the conservation of energy and three momenta at the first order in HI as long as axions are non-relativistic. ...
Chapter 17 Galaxies Galaxies Early Observations
... Measuring the Mass of Galaxies • The mass of a galaxy is determined from the modified form of Kepler’s third law • To use this method, one concentrates on some stars or gas on the outer fringes of the galaxy • The semimajor axis distance used in Kepler’s third law is simply half the galaxy’s pre-det ...
... Measuring the Mass of Galaxies • The mass of a galaxy is determined from the modified form of Kepler’s third law • To use this method, one concentrates on some stars or gas on the outer fringes of the galaxy • The semimajor axis distance used in Kepler’s third law is simply half the galaxy’s pre-det ...
Constraining decaying dark matter with neutron stars
... lifetime, but also in the previous late stages of the progenitor star where the dense nuclear ash central core allows the build-up of a χ -distribution, nχ (r ), over time. In previous works we have considered the effect of a self-annihilating DM particle on the internal NS dynamics [12–15] but here ...
... lifetime, but also in the previous late stages of the progenitor star where the dense nuclear ash central core allows the build-up of a χ -distribution, nχ (r ), over time. In previous works we have considered the effect of a self-annihilating DM particle on the internal NS dynamics [12–15] but here ...
Dark Matter, Dark Energy, and the Fate of the Universe
... greater masses than their luminosities would suggest. That is, when he estimated the total mass of stars necessary to account for the overall luminosity of a cluster, he found that it was far less than the mass he measured by studying galaxy speeds. He concluded that most of the ...
... greater masses than their luminosities would suggest. That is, when he estimated the total mass of stars necessary to account for the overall luminosity of a cluster, he found that it was far less than the mass he measured by studying galaxy speeds. He concluded that most of the ...
the galaxy-halo connection from abundance matching: simplicity
... the mass of a dark matter halo is the primary determinant of its properties. detailed tests of the model can test both LCDM and galaxy formation physics Results to date: matching stellar mass/or luminosity to the maximum mass/vmax its halo ever had (current mass(vmax) for central galaxies; mass at a ...
... the mass of a dark matter halo is the primary determinant of its properties. detailed tests of the model can test both LCDM and galaxy formation physics Results to date: matching stellar mass/or luminosity to the maximum mass/vmax its halo ever had (current mass(vmax) for central galaxies; mass at a ...
Metal-Like Gravity and Its Cosmological Applications
... fields [9]-[12]. While such theories successfully explain much of cosmological dynamics within the realm of GR, they failed to explain the source of such a field. In this paper, such a field is presented by modification of gravitational interaction of two types of mass—one is DM particles and the ot ...
... fields [9]-[12]. While such theories successfully explain much of cosmological dynamics within the realm of GR, they failed to explain the source of such a field. In this paper, such a field is presented by modification of gravitational interaction of two types of mass—one is DM particles and the ot ...
Dark Matter, EDM and bariogenesis
... Thomson scattering cross section, σThomson = 8πα2/3me2, changing the mean-free-path length of photons at recombination and leaving distinct signatures in the ...
... Thomson scattering cross section, σThomson = 8πα2/3me2, changing the mean-free-path length of photons at recombination and leaving distinct signatures in the ...
Dark matter
Dark matter is a hypothetical kind of matter that cannot be seen with telescopes but would account for most of the matter in the universe. The existence and properties of dark matter are inferred from its gravitational effects on visible matter, on radiation, and on the large-scale structure of the universe. Dark matter has not been detected directly, making it one of the greatest mysteries in modern astrophysics.Dark matter neither emits nor absorbs light or any other electromagnetic radiation at any significant level. According to the Planck mission team, and based on the standard model of cosmology, the total mass–energy of the known universe contains 4.9% ordinary matter, 26.8% dark matter and 68.3% dark energy. Thus, dark matter is estimated to constitute 84.5% of the total matter in the universe, while dark energy plus dark matter constitute 95.1% of the total mass–energy content of the universe.Astrophysicists hypothesized the existence of dark matter to account for discrepancies between the mass of large astronomical objects determined from their gravitational effects, and their mass as calculated from the observable matter (stars, gas, and dust) that they can be seen to contain. Their gravitational effects suggest that their masses are much greater than the observable matter survey suggests. Dark matter was postulated by Jan Oort in 1932, albeit based upon insufficient evidence, to account for the orbital velocities of stars in the Milky Way. In 1933, Fritz Zwicky was the first to use the virial theorem to infer the existence of unseen matter, which he referred to as dunkle Materie 'dark matter'. More robust evidence from galaxy rotation curves was discovered by Horace W. Babcock in 1939, but was not attributed to dark matter. The first hypothesis to postulate ""dark matter"" based upon robust evidence was formulated by Vera Rubin and Kent Ford in the 1960s–1970s, using galaxy rotation curves. Subsequently, many other observations have indicated the presence of dark matter in the universe, including gravitational lensing of background objects by galaxy clusters such as the Bullet Cluster, the temperature distribution of hot gas in galaxies and clusters of galaxies and, more recently, the pattern of anisotropies in the cosmic microwave background. According to consensus among cosmologists, dark matter is composed primarily of a not yet characterized type of subatomic particle.The search for this particle, by a variety of means, is one of the major efforts in particle physics today.Although the existence of dark matter is generally accepted by the mainstream scientific community, some alternative theories of gravity have been proposed, such as MOND and TeVeS, which try to account for the anomalous observations without requiring additional matter. However, these theories cannot account for the properties of galaxy clusters.