Related papers: Cosmological Conductive/Cooling Fronts as Lyman Al…
The Lya emission line of HI is intrinsically the brightest feature in the spectrum of astrophysical nebulae, making it a very attractive observational tool with which to survey galaxies. Moreover as a UV resonance line, Lya possesses…
I continue my study of the low-z Lyman alpha cloud population. Previously I showed how galaxy catalogs are used to attribute relative degrees of isolation to those clouds found in HST/GHRS spectra. I find that there exist two distinct…
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…
An astrosphere is a vast, tailed bubble-like volume around a star, formed through the interaction between the stellar magnetic field, the stellar wind, and the interstellar medium (ISM). Detecting and characterizing astrospheres are…
We study the influence of the choice of cooling function on the formation of molecular clouds in high-resolution three-dimensional simulations of converging flows. We directly compare the results obtained using the simple, parametrized…
We have used STIS aboard HST to search for Lyman-alpha (Lya) absorption in the outer regions of nine nearby (cz<6000 km/s) galaxies using background QSOs and AGN as probes. The foreground galaxies are intercepted between 26 and 199 h-1 kpc…
[Abridged] The detection of the rotational lines of CO in proto-galaxies in the early Universe provides one of the most promising ways of probing the fundamental physical properties of a galaxy, such as its size, dynamical mass, gas…
We have performed a detailed statistical study of the evolution of structure in a photoionized intergalactic medium (IGM) using analytical simulations to extend the calculation into the mildly non-linear density regime found to prevail at z…
We examine the Ly-alpha absorber population at z<0.3 detected in spectra of the QSOs PG0953+415 and H1821+643 taken with the Space Telescope Imaging Spectrograph aboard the Hubble Space Telescope. We compare their statistical properties to…
We develop a comprehensive theoretical model for Lyman-alpha emission, from the scale of individual Lyman-alpha emitters (LAEs) to Lyman-alpha halos (LAHs), Lyman-alpha blobs (LABs), and Lyman-alpha filaments (LAFs) of the diffuse cosmic…
We investigate the metal species associated with the Ly$\alpha$ forest in the eBOSS quasar spectra. Metal absorption lines are revealed in the stacked spectra from cross-correlating the selected Ly$\alpha$ absorbers in the forest and the…
An upper limit to the importance of local sources of radiation compared to the cosmic background in cosmological absorption systems is derived, as a simple consequence of the conservation of surface brightness. The limit depends only on the…
We pay particular attention to the high end of the $\lya$ optical depth distribution of a quasar spectrum. Based on the flux distribution (Miralda-Escud\'e et al 1996), a simple yet seemingly cosmological model -differentiating statistic,…
We present a detailed calculation of the propagation of AGN-like ionizing radiation through the intergalactic space. We model the ionization state of absorbing clouds, and show that the universe will be more opaque above $4\,$Ryd than…
It is suggested that a significant fraction of the low column-density absorption features seen in the spectra of quasars are produced in pressure-confined tidal debris, that was built up in small groups and clusters of galaxies over a…
The intergalactic medium (IGM) is believed to contain the majority of baryons in the universe and to trace the same dark matter structure as galaxies, forming filaments and sheets. Lya absorbers, which sample the neutral component of the…
We study the kinematics of the gaseous cosmic web at high redshift with Lyman alpha forest absorption in multiple QSO sightlines. Using a simple analytic model and a cosmological hydrodynamic simulation we constrain the underlying…
We present detailed predictions for the properties of Ly-alpha-emitting galaxies in the framework of the Lambda-CDM cosmology, calculated using the semi-analytical galaxy formation model GALFORM. We explore a model which assumes a top-heavy…
We present STIS 7km/s resolution data of the Ly-a forest toward PKS0405-123 (z=0.574). We make two samples. The strong sample (60 systems) has column density logNHI>13.3 over 0.002<z<0.423, and the weak sample (44) has logNHI>13.1 at…
Lyman-$\alpha$(Ly$\alpha$) forest in the spectra of distant quasars encodes the information of the underlying cosmic density field at smallest scales. The modelling of the upcoming large and high-fidelity forest data using cosmological…