Related papers: QSO Absorption Line Systems
This paper reviews selected aspects of the growth of cosmological structure, covering the following general areas: (1) expected characteristics of linear density perturbations according to various candidate theories for the origin of…
The origin and evolution of structure in the Universe is one of the major questions occupying astronomers today. An understanding of the Lyalpha absorbers seen in QSO spectra is an important part of this program since such absorbers can be…
Recent highly sensitive detections of line emission from extended gas in the local universe demonstrate the feasibility of detecting H$\alpha$ emitting galactic halos out to $z\sim1$. We determine the form of the surface brightness vs.…
Gas-rich galaxies are selected efficiently via quasar absorption lines. Recently, a new perspective on such absorption-selected systems has opened up by studying the molecular gas content of absorber host galaxies using ALMA CO emission…
Models for the formation of galaxies and clusters of galaxies require strong feedback in order to explain the observed properties of these systems. We investigate whether such feedback has observational consequences for the intergalactic…
The physical state of the intergalactic medium can be probed in great detail with the intervening absorption systems seen in quasar spectra. The properties of the Hydrogen absorbers depend on many cosmological parameters, such as the…
Key absorption features in the spectra of massive quiescent galaxies reveal a wealth of information about their stellar populations and, in some cases, the properties of gas within and around them. With the spectroscopic capabilities of…
Intrinsic emission and absorption lines of QSOs provide several independent probes of the metal abundances in QSO environments. They indicate that the metallicities are typically solar or higher out to redshifts z > 4. These results support…
Understanding how galaxies evolved from the early Universe through cosmic time is a fundamental part of modern astrophysics. In order to study this evolution it is important to sample the galaxies at various times in a consistent way…
In this article we discuss the importance of high-resolution absorption spectroscopy for our understanding of the distribution and physical nature of the gaseous circumgalactic medium (CGM) that surrounds the Milky Way. Observational and…
The study of the morphology of galaxies is important in order to understand the formation and evolution of galaxies and their sub-components as a function of luminosity, environment, and star-formation and galaxy assembly over cosmic time.…
Randomly oriented flattened spheroids have been used to describe a broad range of astrophysical phenomena. Here we use this geometric approach to derive equations representing lines of sight through quasar absorption clouds to constrain…
(Sub-)millimeter spectral lines can be used not only to understand the chemical complexity and enrichment history of an observed portion of our Galaxy, but with spectrally resolved lines, they reveal the physical conditions, dynamics, and…
We present results of surveys for high redshift field galaxies selected by their having produced detectable absorption in the spectra of background QSOs. Such surveys, in essence selected by gas cross-section rather than by flux density,…
Galactic accretion interacts in complex ways with gaseous halos, including galactic winds. As a result, observational diagnostics typically probe a range of intertwined physical phenomena. Because of this complexity, cosmological…
It is possible to distinguish ``intrinsic'' absorption systems (gas clouds within the quasar environment) from ``intervening'' systems (gas clouds unrelated to the quasar phenomenon) by considering certain observational properties. We find…
We use a gaseous model and a semi-analytical approach to study the evolution of a super-massive central gaseous object (a super-massive star, (SMS from now on) in an AGN and its evolution by interactions with the surrounding stellar system.…
Modern theories of galaxy formation predict that galaxies impact on their gaseous surroundings, playing the fundamental role of regulating the amount of gas converted into stars. While star-forming galaxies are believed to provide feedback…
Gamma-ray line observations provide a versatile tool for studies of nucleosynthesis processes and supernova physics. In particular, the observation of radioactive species in the interstellar medium probes recent nucleosynthesis activity on…
The spectrum emitted by the Broad Emission Line Regions of Active Galactic Nuclei can measure the luminosity of the central object and the chemical composition of the interstellar medium in a very young galaxy, and so constrain the…