相关论文: HI and Cosmology: What We Need To Know
The question of whether intelligent life exists elsewhere is one of the fundamental unknowns about our Universe. Over the past decade more than 200 extra-solar planets have been discovered, providing new urgency for addressing this question…
Observations at long wavelengths, in the wide interval from a few to 1000 micron, are essential to study diffuse media in galaxies, including all kinds of atomic, ionic and molecular gases and dust grains. Hence they are particularly suited…
Cosmic background radiation, both diffuse and discrete in nature, produced at different cosmic epochs before and after recombination, provides key information on the evolution of cosmic structures. We discuss the main classes of sources…
In the quest for precision cosmology, one must ensure that the cosmology is accurate as well. We discuss figures of merit for determining from observations whether the dark energy is a cosmological constant or dynamical, with special…
The Universe is not completely homogeneous. Even if it is sufficiently so on large scales, it is very inhomogeneous at small scales, and this has an effect on light propagation, so that the distance as a function of redshift, which in many…
Cosmological observations offer unique and robust avenues for probing the fundamental nature of dark matter particles-they broadly test a range of compelling theoretical scenarios, often surpassing or complementing the reach of terrestrial…
Understanding the Universe's origins and evolution remains one of the most fundamental challenges in modern cosmology. This white paper explores three key science priorities in this field: unravelling the physics of cosmic inflation,…
Fluctuations in high-redshift cosmic 21-cm radiation provide a new window for observing unconventional effects of high-energy physics in the primordial spectrum of density perturbations. In scenarios for which the initial state prior to…
We review some of the major contributions that the Square Kilometer Array (SKA) will provide for Cosmology. We discuss the SKA measurements of the equation of state parameter for dark energy from Baryonic Acoustic Oscillations (BAO), of the…
Line intensity mapping (LIM) proposes to efficiently observe distant faint galaxies and map the matter density field at high redshift. Building upon the formalism in the companion paper, we first highlight the degeneracies between cosmology…
This year marks the 20th anniversary of the effective beginning of large, systematic redshift surveys of galaxies. These surveys have had a major impact on observational cosmology and on our current understanding of large-scale structures…
The explanation of the accelerated expansion of the Universe poses one of the most fundamental questions in physics and cosmology today. If the acceleration is driven by some form of dark energy, one can try to constrain the parameters…
Cosmography is a phenomenological and relatively model-independent approach to cosmology, where physical quantities are expanded as a Taylor series in the cosmological redshift, or in related variables. Here we apply this methodology to…
The SKA is a unique instrument to open a window on many aspects of galaxy formation and evolution which can be examined in our Local Universe. Here I will focus on the outermost regions of galaxies which can be observed with sufficient…
The Square Kilometre Array (SKA) will transform our understanding of the role of the cold, atomic gas in galaxy evolution. The interstellar medium (ISM) is the repository of stellar ejecta and the birthsite of new stars and, hence, a key…
The three-dimensional distribution of astronomical objects observed in redshift space significantly differs from the true distribution since the distance to each object cannot be determined by its redshift $z$ only; for $z \ll 1$ the…
Studies of the cosmic dark ages ($30 \lesssim z \lesssim 150$) using the highly redshifted 21 cm line of neutral hydrogen offer unparalleled amounts of cosmological information, and recent years have seen the refinement of concepts for such…
Line-intensity mapping (LIM) provides a promising way to probe cosmology, reionization and galaxy evolution. However, its sensitivity to cosmology and astrophysics at the same time is also a nuisance. Here we develop a comprehensive…
Large inhomogeneities in neutral hydrogen in the universe can be detected at redshifts $z \leq 10$ using the redshifted 21cm line emission from atomic hydrogen. This paper reviews the expected evolution of neutral hydrogen and presents…
Emission lines in hydrogen can be used to measure the approximate redshift of the reionization of the universe. This is an important measurement given the lack of a convincing theoretical prediction of this epoch. There is a rapid change in…