This paper suggests explanations for otherwise seemingly unexplained data about elementary particles and cosmology. The explanations have bases in coordinate-based modeling and in integer-based characterizations for s...This paper suggests explanations for otherwise seemingly unexplained data about elementary particles and cosmology. The explanations have bases in coordinate-based modeling and in integer-based characterizations for some catalogs. One catalog features properties—including charge, mass, and angular momentum—of objects. Another catalog features all known and some possible elementary particles. Assumptions include that multipole-expansion mathematics has uses regarding long-range interactions, such as gravity, and that nature includes six isomers of all elementary particles other than long-range-interaction bosons. One isomer associates with ordinary matter. Five isomers are associated with dark matter. Multipole notions help explain large-scale aspects such as the rate of expansion of the universe.展开更多
The formation of galaxies with warm dark matter is approximately adiabatic. The cold dark matter limit is singular and requires relaxation. In these lecture notes, we develop, step-by-step, the physics of galaxies wit...The formation of galaxies with warm dark matter is approximately adiabatic. The cold dark matter limit is singular and requires relaxation. In these lecture notes, we develop, step-by-step, the physics of galaxies with warm dark matter, and their formation. The theory is validated with observed spiral galaxy rotation curves. These observations constrain the properties of the dark matter particles.展开更多
We try to bridge the gap between the theory of linear density-velocity-gravitational perturbations in the early universe, and the relaxed galaxies we observe today. We succeed quantitatively for dark matter if dark ma...We try to bridge the gap between the theory of linear density-velocity-gravitational perturbations in the early universe, and the relaxed galaxies we observe today. We succeed quantitatively for dark matter if dark matter is warm. The density runs of baryons and of dark matter of relaxed galaxies are well described by hydro-static equations. The evolution from initial linear perturbations to final relaxed galaxies is well described by hydro-dynamical equations. These equations necessarily include dark matter velocity dispersion. If the initial perturbation is large enough, the halo becomes self-gravitating. The adiabatic compression of the dark matter core determines the final core density, and provides a negative stabilizing feedback. The relaxed galaxy halo may form adiabatically if dark matter is warm. The galaxy halo radius continues to increase indefinitely, so has an ill-defined mass.展开更多
Based on the recently developed numerical approach to understand the formation and the chemical evolution of the milky-way galaxy in the solar neighborhood we study the influence of the supernova type SN Ia rates on t...Based on the recently developed numerical approach to understand the formation and the chemical evolution of the milky-way galaxy in the solar neighborhood we study the influence of the supernova type SN Ia rates on the galactic chemical evolution. Supernova SN Ia plays an important role in producing the iron inventory of the galaxy. We also study the dependence of the chemical evolution on the star formation rate prevailing during the initial one billion years of the evolution of the galaxy. This era marks the formation of the galactic halo and the thick disk. A comparison of the elemental abundance distributions of the dwarf stars in the solar neighborhood is made among the various models simulated in the present work. In order to explain the majority of the observed elemental evolutionary trends, specifically those related with the galactic evolution of iron and oxygen, it would be essential to incorporate a major component of prompt SN Ia to the galactic evolution. The prompt SN Ia would produce significant fraction of SN Ia within the initial ~100 million years from the time of star formation. The essential requirement of prompt SN Ia would result in a significant enhancement of SN Ia rates during the earliest epoch of the galaxy. The elemental evolutionary trends also favor an enhancement in the star formation rate during the initial one billion years of the galaxy at least by a factor of three compared to the trend prevailing during the latter evolutionary time of the galaxy.展开更多
I present a large set of high resolution simulations, called CosmicGrowth Simulations, which were generated with either 8.6 billion or 29 billion particles. As for the nominal cosmological model that can match nearly ...I present a large set of high resolution simulations, called CosmicGrowth Simulations, which were generated with either 8.6 billion or 29 billion particles. As for the nominal cosmological model that can match nearly all observations on cosmological scales, I have adopted a flat Cold Dark Matter(CDM) model with a cosmological constant Λ(ΛCDM). The model parameters have been taken either from the latest result of the WMAP satellite(WMAP ΛCDM) or from the first year's result of the Planck satellite(Planck ΛCDM). Six simulations are produced in the ΛCDM models with two in the Planck model and the others in the WMAP model. In order for studying the non-linear evolution of the clustering, four simulations were also produced with 8.6 billion particles for the scale-free models of an initial power spectrum P(k) ∝ k^n with n = 0,-1,-1.5 or-2.0. Furthermore, two radical CDM models(XCDM) are simulated with 8.6 billion particles each. Since the XCDM have some of the model parameters distinct from those of the ΛCDM models, they must be unable to match the observations, but are very useful for studying how the clustering properties depend on the model parameters. The Friends-of-Friends(FoF) halos were identified for each snapshot and subhalos were produced by the Hierarchical Branch Tracing(HBT) algorithm. These simulations form a powerful database to study the growth and evolution of the cosmic structures both in theory and in observation.展开更多
The recent discovery of gravitational waves has revolutionized our understanding of many aspects regarding how the universe works. The formation of galaxies stands as one of the most challenging problems in astrophysi...The recent discovery of gravitational waves has revolutionized our understanding of many aspects regarding how the universe works. The formation of galaxies stands as one of the most challenging problems in astrophysics. Regardless of how far back we look in the early universe, we keep discovering galaxies with supermassive black holes lurking at their centers. Many models have been proposed to explain the rapid formation of supermassive black holes, including the massive accretion of material, the collapse of type III stars, and the merger of stellar mass black holes. Some of these events give rise to the production of gravitational waves that could be detected by future generations of more sensitive detectors. Alternatively, the existence of these supermassive black holes can be explained in the context of primordial black holes. In this paper we discuss the various models of galaxy formation shedding light on the role that gravitational waves can play to test of the validity of some of these models. We also discuss the prospect of primordial black holes as a seeding constituent for galaxy formation.展开更多
A Viable scenario for globula r cluster formation is suggested in CDM model.In this scenario the smaller scale fluctuations superpo sed on proto-galaxy will form proto-dwarf-galaxies. In their multi-phase ISM the warm...A Viable scenario for globula r cluster formation is suggested in CDM model.In this scenario the smaller scale fluctuations superpo sed on proto-galaxy will form proto-dwarf-galaxies. In their multi-phase ISM the warm clouds,which are thermally stable and gravitationally marginally stable with appropriate masses and metallicities, might be the proper progenitors of GCs.In the virialization of a proto-galaxy,these dwarf galaxies will acquire kinetic energy and collide with each other. As strong external disturbances. these collisions will cause a short timescale thermal instability,and further stimulate gravitational instability which is necessary for the transformation of progenitors into GCs.展开更多
The manner the galaxy accretes matter, along with the star formation rates at different epochs, influences the evolution of the stable isotopic inventories of the galaxy. A detailed analysis is presented here to study...The manner the galaxy accretes matter, along with the star formation rates at different epochs, influences the evolution of the stable isotopic inventories of the galaxy. A detailed analysis is presented here to study the dependence of the galactic chemical evolution on the accretion scenario of the galaxy along with the star formation rate during the early accretionary phase of the galactic thick disk and thin disk. Our results indicate that a rapid early accretion of the galaxy during the formation of the galactic thick disk along with an enhanced star formation rate in the early stages of the galaxy accretion could explain the majority of the galactic chemical evolution trends of the major elements. Further, we corroborate the recent suggestions regarding the formation of a massive galactic thick disk rather than the earlier assumed low mass thick disk.展开更多
We investigate the fabric of spacetime, its ability to stretch, curve, and expand. Through our continuous studies of accretion disks located at the core of galaxies, it is our conclusion that these disks are separate ...We investigate the fabric of spacetime, its ability to stretch, curve, and expand. Through our continuous studies of accretion disks located at the core of galaxies, it is our conclusion that these disks are separate from the host galaxy stellar disk. Our research has also determined that the radius of accretion disks in spiral galaxies follow a consistent ratio according to the circumference of their adjacent supermassive black hole based on its Schwarzchild radius. We present evidence suggesting that galactic accretion disks are a key element to understand galaxy formation and can provide a precise calculation to how much the fabric of space will stretch. Once the degree of the elasticity of spacetime was established, we applied these measurements to the size of the universe at 380,000 years of age based on the imagery of the cosmic microwave background. This calculation provided us with the maximum diameter the universe will reach, an exact time when the universe will stop expanding, and where we are today within that timeline.展开更多
星系形成的半解析模型是理解星系形成中的重子物理过程的重要方法,但存在显著的缺点:物理参数太多,调控过程复杂。MCMC(Markov chain Monte Carlo)方法是现代统计计算中最重要的算法之一,通过MCMC方法可以得到星系形成半解析模型中众多...星系形成的半解析模型是理解星系形成中的重子物理过程的重要方法,但存在显著的缺点:物理参数太多,调控过程复杂。MCMC(Markov chain Monte Carlo)方法是现代统计计算中最重要的算法之一,通过MCMC方法可以得到星系形成半解析模型中众多物理参数的有效范围。简要介绍了半解析模型的主要物理过程和MCMC方法,综述了近年来MCMC方法在星系形成半解析模型中的应用和成果。这些结果表明MCMC方法对于限制半解析模型有很好的作用,对更好地理解星系形成中的物理过程起到促进作用。展开更多
文摘This paper suggests explanations for otherwise seemingly unexplained data about elementary particles and cosmology. The explanations have bases in coordinate-based modeling and in integer-based characterizations for some catalogs. One catalog features properties—including charge, mass, and angular momentum—of objects. Another catalog features all known and some possible elementary particles. Assumptions include that multipole-expansion mathematics has uses regarding long-range interactions, such as gravity, and that nature includes six isomers of all elementary particles other than long-range-interaction bosons. One isomer associates with ordinary matter. Five isomers are associated with dark matter. Multipole notions help explain large-scale aspects such as the rate of expansion of the universe.
文摘The formation of galaxies with warm dark matter is approximately adiabatic. The cold dark matter limit is singular and requires relaxation. In these lecture notes, we develop, step-by-step, the physics of galaxies with warm dark matter, and their formation. The theory is validated with observed spiral galaxy rotation curves. These observations constrain the properties of the dark matter particles.
文摘We try to bridge the gap between the theory of linear density-velocity-gravitational perturbations in the early universe, and the relaxed galaxies we observe today. We succeed quantitatively for dark matter if dark matter is warm. The density runs of baryons and of dark matter of relaxed galaxies are well described by hydro-static equations. The evolution from initial linear perturbations to final relaxed galaxies is well described by hydro-dynamical equations. These equations necessarily include dark matter velocity dispersion. If the initial perturbation is large enough, the halo becomes self-gravitating. The adiabatic compression of the dark matter core determines the final core density, and provides a negative stabilizing feedback. The relaxed galaxy halo may form adiabatically if dark matter is warm. The galaxy halo radius continues to increase indefinitely, so has an ill-defined mass.
文摘Based on the recently developed numerical approach to understand the formation and the chemical evolution of the milky-way galaxy in the solar neighborhood we study the influence of the supernova type SN Ia rates on the galactic chemical evolution. Supernova SN Ia plays an important role in producing the iron inventory of the galaxy. We also study the dependence of the chemical evolution on the star formation rate prevailing during the initial one billion years of the evolution of the galaxy. This era marks the formation of the galactic halo and the thick disk. A comparison of the elemental abundance distributions of the dwarf stars in the solar neighborhood is made among the various models simulated in the present work. In order to explain the majority of the observed elemental evolutionary trends, specifically those related with the galactic evolution of iron and oxygen, it would be essential to incorporate a major component of prompt SN Ia to the galactic evolution. The prompt SN Ia would produce significant fraction of SN Ia within the initial ~100 million years from the time of star formation. The essential requirement of prompt SN Ia would result in a significant enhancement of SN Ia rates during the earliest epoch of the galaxy. The elemental evolutionary trends also favor an enhancement in the star formation rate during the initial one billion years of the galaxy at least by a factor of three compared to the trend prevailing during the latter evolutionary time of the galaxy.
基金supported by the National Natural Science Foundation of China(Grant Nos.11320101002,11533006,and 11621303)the National Program on Key Basic Research Project(Grant No.2015CB857003)
文摘I present a large set of high resolution simulations, called CosmicGrowth Simulations, which were generated with either 8.6 billion or 29 billion particles. As for the nominal cosmological model that can match nearly all observations on cosmological scales, I have adopted a flat Cold Dark Matter(CDM) model with a cosmological constant Λ(ΛCDM). The model parameters have been taken either from the latest result of the WMAP satellite(WMAP ΛCDM) or from the first year's result of the Planck satellite(Planck ΛCDM). Six simulations are produced in the ΛCDM models with two in the Planck model and the others in the WMAP model. In order for studying the non-linear evolution of the clustering, four simulations were also produced with 8.6 billion particles for the scale-free models of an initial power spectrum P(k) ∝ k^n with n = 0,-1,-1.5 or-2.0. Furthermore, two radical CDM models(XCDM) are simulated with 8.6 billion particles each. Since the XCDM have some of the model parameters distinct from those of the ΛCDM models, they must be unable to match the observations, but are very useful for studying how the clustering properties depend on the model parameters. The Friends-of-Friends(FoF) halos were identified for each snapshot and subhalos were produced by the Hierarchical Branch Tracing(HBT) algorithm. These simulations form a powerful database to study the growth and evolution of the cosmic structures both in theory and in observation.
文摘The recent discovery of gravitational waves has revolutionized our understanding of many aspects regarding how the universe works. The formation of galaxies stands as one of the most challenging problems in astrophysics. Regardless of how far back we look in the early universe, we keep discovering galaxies with supermassive black holes lurking at their centers. Many models have been proposed to explain the rapid formation of supermassive black holes, including the massive accretion of material, the collapse of type III stars, and the merger of stellar mass black holes. Some of these events give rise to the production of gravitational waves that could be detected by future generations of more sensitive detectors. Alternatively, the existence of these supermassive black holes can be explained in the context of primordial black holes. In this paper we discuss the various models of galaxy formation shedding light on the role that gravitational waves can play to test of the validity of some of these models. We also discuss the prospect of primordial black holes as a seeding constituent for galaxy formation.
基金Project supported by the National Natural Science Foundation of China
文摘A Viable scenario for globula r cluster formation is suggested in CDM model.In this scenario the smaller scale fluctuations superpo sed on proto-galaxy will form proto-dwarf-galaxies. In their multi-phase ISM the warm clouds,which are thermally stable and gravitationally marginally stable with appropriate masses and metallicities, might be the proper progenitors of GCs.In the virialization of a proto-galaxy,these dwarf galaxies will acquire kinetic energy and collide with each other. As strong external disturbances. these collisions will cause a short timescale thermal instability,and further stimulate gravitational instability which is necessary for the transformation of progenitors into GCs.
文摘The manner the galaxy accretes matter, along with the star formation rates at different epochs, influences the evolution of the stable isotopic inventories of the galaxy. A detailed analysis is presented here to study the dependence of the galactic chemical evolution on the accretion scenario of the galaxy along with the star formation rate during the early accretionary phase of the galactic thick disk and thin disk. Our results indicate that a rapid early accretion of the galaxy during the formation of the galactic thick disk along with an enhanced star formation rate in the early stages of the galaxy accretion could explain the majority of the galactic chemical evolution trends of the major elements. Further, we corroborate the recent suggestions regarding the formation of a massive galactic thick disk rather than the earlier assumed low mass thick disk.
文摘We investigate the fabric of spacetime, its ability to stretch, curve, and expand. Through our continuous studies of accretion disks located at the core of galaxies, it is our conclusion that these disks are separate from the host galaxy stellar disk. Our research has also determined that the radius of accretion disks in spiral galaxies follow a consistent ratio according to the circumference of their adjacent supermassive black hole based on its Schwarzchild radius. We present evidence suggesting that galactic accretion disks are a key element to understand galaxy formation and can provide a precise calculation to how much the fabric of space will stretch. Once the degree of the elasticity of spacetime was established, we applied these measurements to the size of the universe at 380,000 years of age based on the imagery of the cosmic microwave background. This calculation provided us with the maximum diameter the universe will reach, an exact time when the universe will stop expanding, and where we are today within that timeline.
文摘星系形成的半解析模型是理解星系形成中的重子物理过程的重要方法,但存在显著的缺点:物理参数太多,调控过程复杂。MCMC(Markov chain Monte Carlo)方法是现代统计计算中最重要的算法之一,通过MCMC方法可以得到星系形成半解析模型中众多物理参数的有效范围。简要介绍了半解析模型的主要物理过程和MCMC方法,综述了近年来MCMC方法在星系形成半解析模型中的应用和成果。这些结果表明MCMC方法对于限制半解析模型有很好的作用,对更好地理解星系形成中的物理过程起到促进作用。
