Related papers: Atomic Data Revisions for Transitions Relevant to …
We update the online SpectroWeb database of spectral standard reference stars with 1178 oscillator strength values of atomic absorption lines observed in the optical spectrum of the Sun and Procyon (Alpha CMi A). The updated line oscillator…
A broad array of interstellar absorption features that appear in the ultraviolet spectra of bright sources allows us to measure the abundances and ionization states of many important heavy elements that exist as free atoms in the…
We present results of a blind search for Galactic HI 21-cm absorption lines toward 19130 radio sources, using 390 pointings of MALS, each pointing centered on a source brighter than 200 mJy. We detected 3640 HI absorption features. This…
We examine the absorption line spectra of a sample of 31 luminous (M_UV=-23) Lyman break galaxies at redshift z~6 using data taken with the FOCAS and OSIRIS spectrographs on the Subaru and GTC telescopes. For two of these sources we present…
The circumgalactic medium (CGM) remains one of the least constrained components of galaxies and as such has significant potential for advancing galaxy formation theories. In this work, we vary the extragalactic ultraviolet background for a…
Molecular line data for the rotational transitions of a number of astrophysically interesting species have been collected and are made publically available through the www. These data, including energy levels, statistical weights, Einstein…
Gas flows in and out of galaxies through their circumgalactic medium (CGM) are poorly constrained and direct observations of this faint, diffuse medium remain challenging. We use a sample of five $z$ $\sim$ 1-2 galaxy counterparts to Damped…
To characterize the absorption properties of this circumgalactic medium (CGM) and its relation to the LG we present the so-far largest survey of metal absorption in Galactic high-velocity clouds (HVCs) using archival ultraviolet (UV)…
Low-ionization metal absorption lines provide a primary probe of cool gas in and around galaxies. We confront observations of metal-line absorption in quasar spectra with predictions from the IllustrisTNG cosmological simulation in order to…
The origin of warm ions in the circum-galactic medium (CGM) surrounding massive galaxies remains a mystery. In this paper, we argue that a significant fraction of the observed warm-ion columns may arise in the intergalactic medium (IGM)…
Fundamental atomic transition parameters, such as oscillator strengths and wavelengths, play a key role in modelling and understanding the chemical composition of stars in the universe. Despite the significant work under way to produce…
Recent observations suggest molecular line ratios in millimeter and submillimeter bands may be a good tool to reveal the long-standing question on the origin of energy sources in obscured active galaxies -- AGN and/or starburst.…
We present the target selection, observations, and data reduction and analysis process for a program aimed at discovering numerous, weak (equivalent width < 100 mA) Lya absorption lines in the local Universe (0.003 < z < 0.069). The purpose…
The filamentary network of intergalactic medium (IGM) gas that gives origin to the Lyman-alpha forest in the spectra of distant quasars encodes information on the physics of structure formation and the early thermodynamics of diffuse…
We present an absorption-line survey of optically thick gas clouds -- Lyman Limit Systems (LLSs) -- observed at high dispersion with spectrometers on the Keck and Magellan telescopes. We measure column densities of neutral hydrogen NHI and…
In recent years, the study of the Milky Way has significantly advanced due to extensive spectroscopic surveys of its stars, complemented by astroseismic and astrometric data. However, it remains disjoint from recent advancements in…
We present new simulations of Lyman-$\alpha$ (Ly$\alpha$) intensity maps that include Ly$\alpha$ radiative transfer in the intergalactic medium (IGM) and all significant sources of Ly$\alpha$ photons. The sources considered include…
The Magellanic Stream, a tidal tail of diffuse gas falling onto the Milky Way, formed by interactions between the Small and Large Magellanic Clouds, is primarily composed of neutral atomic hydrogen (HI). The deficiency of dust and the…
Determining when and how the first galaxies reionized the intergalactic medium (IGM) promises to shed light on both the nature of the first objects and the cosmic history of baryons. Towards this goal, quasar absorption lines play a unique…
The sky-averaged (global) 21-cm signal is a powerful probe of the intergalactic medium (IGM) prior to the completion of reionization. However, it has so far been unclear that even in the best case scenario, in which the signal is accurately…