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This chapter focuses on how gamma-ray bursts (GRBs) are emerging as unique tools in the study of broad areas of astronomy and physics by virtue of their special properties. The unassailable fact about GRBs that makes them such great probes is that they are fantastically bright and so can be seen to the farthest reaches of the observable Universe. In parallel with the ongoing study of GRB events and progenitors, new lines of inquiry have burgeoned: using GRBs as unique probes of the Universe in ways that are almost completely divorced from the nature of GRBs themselves. Topics discussed include studies of gas, dust, and galaxies; the history of star formation; measuring reionization and the first objects in the universe; neutrinos, gravitational waves, and cosmic rays; quantum gravity and the expansion of the universe; and the future of GRBs.

This chapter studies how the n-point correlation functions have proved useful not only as descriptive statistics but also as dynamic variables in the Newtonian theory of the evolution of clustering. It generalizes the functions to mass correlation functions in position and momentum, and derives the BBGKY hierarchy of equations for their evolution. This yields a new way to analyze the evolution of mass clustering in an expanding universe. Of course, the main interest in the approach comes from the thought that the observed galaxy correlation functions may yield useful approximations to the mass correlation functions, so the observations may provide boundary values for the dynamical theory of evolution of the mass correlation functions. The test will be whether one can find a consistent theory for the joint distributions in galaxy positions and velocities.

This chapter begins by providing a brief description of Harlow Shapley's biography and early life. It then discusses Harlow's life as a student of the University of Missouri and Princeton. It narrates his study with Henry Norris Russell about the discovery of approximate mathematical methods for analysing the behaviour of binary stars. It tells of Shapley's efforts to make himself known in other places. It mentions Shapley's other important works such as his guess that RR Lyrae variables might also be standard candles, the distances of the globular clusters, the discovery of the centre of the Milky Way, and finding the Sculptor and Fornax dwarf galaxies. It also tells of the criticisms and oppositions that he encountered.

This chapter examines galaxies in some detail from a largely theoretical perspective. Along the way, one must bear in mind that, although the described progression of events in this chapter is plausible, at this time it is only a conjecture in the minds of theorists that has not yet been confirmed by observational data. This chapter therefore focuses only on the physics that drive these interstellar objects, showing how the earliest dwarf galaxies eventually merged and made bigger galaxies. A present-day galaxy like our own Milky Way was constructed over cosmic history by the assembly of a million building blocks in the form of the first dwarf galaxies.

This chapter studies the presence of “subliminal matter.” The presence of significant mass in subluminal matter was first suggested in the 1930s by the surprisingly large velocities of galaxies in clusters of galaxies. The chapter traces the history of discovery of astronomical evidence of subluminal matter in large clusters of galaxies, in groups of a few or just two galaxies that are close enough that they seem likely to be gravitationally bound, and in individual spiral galaxies. There must be enough mass in spirals to account for the circular velocities of disk stars, and the mass rotationally supported in the disk must be large enough that gravity can form spiral arms, but this mass component cannot be so large that the spiral arms grow to destroy the observed nearly circular motions in the disk. These conditions require that most of the mass in a spiral galaxy is in a stable subluminal massive halo draped around the outskirts of the luminous parts of the galaxy.

This chapter traces the history of the development of ideas on the large-scale structure of the universe. Modern discussions of the nature of the large-scale matter distribution can be traced back to three central ideas. In 1917, Albert Einstein argued that a closed homogeneous world model fits very well into general relativity theory and the requirements of Mach's principle. In 1926, Edwin Hubble showed that the large-scale distribution of galaxies is close to uniform with no indication of an edge or boundary. In 1927, Georges Lemaître showed that the uniform distribution of galaxies fits very well with the pattern of galaxy redshifts. The chapter then assesses several questions. The first is whether the universe really is homogeneous. Could the homogeneity of the universe have been deduced ahead of time from general principles? Or might it be a useful guide to new principles? It also asks how clustering evolves in an expanding universe, what its origin is, and what this reveals about the nature of the universe.

This chapter explores the statistical pattern of the galaxy distribution. It focuses on n-point correlation functions (analogs of the autocorrelation function and higher moments for a continuous function), the descriptive statistics that have proved useful. The approach has also proved useful in many other applications. Of considerable practical importance has been the fact that there is a simple linear equation relating the directly observable angular correlation function to the wanted spatial function. This means the translation from one to the other is fairly easy, and equally important it makes it easy to say how the statistical estimates ought to scale with the depth of the survey and hence to test for possible contamination of the estimates by systematic errors. A third useful result is that the dynamics of the galaxy distribution can be treated in terms of the mass correlation functions: the statistic that proves useful for the reduction of the data may also be useful for the analysis of the theory.

This chapter presents the full relativistic analysis of the evolution of mass clustering. The full relativistic theory is needed to deal with three important aspects of density irregularities in the early universe. First, when the pressure is high the relativistic active gravitational mass and inertial mass associated with pressure affect the dynamics. Second, when the mean density is high, a fluctuation of even modest fractional amount containing a modest mass can have a large effect on the space curvature. One is thus led to deal with the interaction of speculations on the nature of the mass distribution and of the geometry in the early universe. Third, the horizon shrinks to zero at the time of the big bang: the seed fluctuations out of which galaxies might form were larger than the horizon and so were not in causal connection reckoned from the time of the big bang. Of course, this curious point applies as well to the homogeneous background: it was somehow contrived that all parts of the universe now visible were set expanding with quite precise uniformity even though an observer could not have discovered this much before the present epoch.

Results from the LHC can expand our knowledge of the early stages of the universe. The connection between the world of particle physics and the structure of our universe is probably one of the most profound results of modern science, which captivates the imagination of anyone who is confronted with its wonders. This chapter describes this connection, explaining how the process of inflation could be at the origin of the cosmological properties we observe today. The empirical evidence in favour of dark matter is by now overwhelming. This still unknown form of matter could be made of some new kind of particle that can be produced at the LHC. This chapter presents the case of dark matter at the LHC and the ways in which the new form of matter could be discovered. It explains what dark energy is and its potential impact on the naturalness problem.

Computer simulators offer a powerful approach for studying complex physical systems. We consider their use in current practice and the role of external uncertainty in bridging the gap between the properties of the model and of the system. The interpretation of this uncertainty analysis raises questions about the role and meaning of the Bayesian approach. We summarize some theory which is helpful to clarify and amplify the role of external specifications of uncertainty, and illustrate some of the types of calculation suggested by this approach.

Chapter 3 introduces to the political, social and cultural opportunities for the extreme right in Germany, Italy and the United States, pointing at the mix of similarities and differences between the three countries. As the authors explain, Germany and Italy were chosen within a ‘most similar’ logic, where the cases under examination share similarities in most of their characteristics, but some differences in our set of dependent variables (the frames, networks and actions of the extremist right), which are then explained by some contextual differences. The addition of the rather different case of the US extreme right aimed at testing the generalizability of some descriptive and causal inferences that emerged in the previous comparison.

This chapter examines why in the early 1980s cosmologists co-opted the astronomers' subluminal mass and the particle physicists' nonbaryonic matter in what became known as the standard cold dark matter, or sCDM, cosmological model. The letter “s” might be taken to mean that the model was designed to be simple (as it was) but it instead signified “standard,” not because it was established but because it came first. A large part of the cosmology community soon adopted variants of the sCDM model as bases for exploration of how galaxies might have formed in the observed patterns of their space distribution and motions, and for analyses of the effect of galaxy formation on the angular distribution of the sea of thermal radiation. This widespread adoption was arguably overenthusiastic, because it was easy to devise other models, less simple to be sure, that fit what we knew at the time. And it was complicated by the nonempirical feeling that space sections surely are flat.

This chapter describes the essential aspects of the modern cosmological paradigm for understanding the formation of the first galaxies in the Universe. The basic question that cosmology attempts to answer is: What is the composition of the Universe and what initial conditions generated the observed structures in it? The first galaxies were shaped, more than any other class of astrophysical objects, by the pristine initial conditions and basic constituents of the Universe. This chapter shows how studying the formation process of the first galaxies could reveal unique evidence for new physics that has so far remained veiled in older galaxies by complex astrophysical processes.

This chapter examines the intergalactic medium (IGM). Although much of astronomy focuses on the luminous material inside galaxies, the majority of matter today—and the vast majority at z > 6—actually lies outside these structures, in the IGM. This material ultimately provides the fuel for galaxy and cluster formation and—because it is much less affected by the complex physics of galaxies—offers a cleaner view of the underlying physical processes of structure formation and of fundamental cosmology. The chapter thus takes up the study on the properties of the IGM, especially during the era of the first galaxies (when the IGM underwent major changes).

This chapter investigates a number of specific observational probes of the high-redshift Universe. It examines the Lyman-α‎ line, an extraordinarily rich and useful—albeit complex—probe of both galaxies and the intergalactic medium (IGM). As established in the previous chapter, young star-forming galaxies can produce very bright Lyman-α‎ emissions. Although the radiative transfer of these photons through their host galaxies is typically very complex, a good starting point is a simple model in which a fraction of stellar ionizing photons are absorbed within their source galaxy, forming embedded H II regions. The resulting protons and electrons then recombine, producing Lyman-α‎ photons. Assuming ionization equilibrium, the rate of these recombinations must equal the rate at which ionizing photons are produced.