Related papers: X-ray Absorption by the Low-redshift Intergalactic…
The circumgalactic medium (CGM) around galaxies is believed to record various forms of galaxy feedback and contain a significant portion of the "missing baryons" of individual dark matter halos. However, clear observational evidence for the…
With the Chandra X-ray Telescope we have detected a zero-redshift OVII He-alpha absorption line along the sight line toward 3C 273. This line detection is highly significant, with a signal-to-noise ratio (S/N) of 6.4. We explore two models,…
We present a survey for metal absorption systems traced by neutral oxygen over $3.2 < z < 6.5$. Our survey uses Keck/ESI and VLT/X-Shooter spectra of 199 QSOs with redshifts up to 6.6. In total we detect 74 O I absorbers, of which 57 are…
The low-redshift Ly-alpha forest of absorption lines provides a probe of large-scale baryonic structures in the intergalactic medium, some of which may be remnants of physical conditions set up during the epoch of galaxy formation. We…
Observations with the Swift satellite of X-ray afterglows of more than a hundred gamma ray bursts (GRBs) with known redshift reveal ubiquitous soft X-ray absorption. The directly measured optical depth \tau at a given observed energy is…
Observations from the HUT and the HST have recently detected HeII absorption along the lines of sight to two high redshift quasars. We use cosmological simulations with gas dynamics to investigate HeII absorption in the cold dark matter…
The distribution of neutral hydrogen in the intergalactic medium (IGM) is currently explored at low-z by means of UV spectroscopy of quasars. We propose an alternative approach based on UV colours of quasars as observed from GALEX surveys.…
X-ray absorption of high-redshift quasars is enigmatic, because it remains unclear where in the universe the absorbing gas is. If absorption occurs near the high-z host, it could help us understand early stages of galaxy formation. If it is…
We determined oxygen and iron abundances of the interstellar medium (ISM) using K-shell (O) and L-shell (Fe) X-ray photo-ionization edges towards Ultra luminous X-ray sources (ULXs). We determine the hydrogen column densities (n_H) towards…
Recent STIS and FUSE observations have detected OVI absorption lines at low redshift that are not clearly associated with any galactic system. In this paper, we argue that these lines are due to metal enriched hot gas in the intergalactic…
We characterize the properties of the intergalactic medium (IGM) around a sample of galaxies extracted from state-of-the-art hydrodynamical simulations of structure formation in a cosmological volume of 25 Mpc comoving at $z\sim 2$. The…
The problem of missing baryons in the local universe remains an open question. One propose alternative is that at low redshift missing baryons are in the form of the Warm Hot Intergalactic Medium (WHIM). In order to test this idea, we…
In hierarchical cosmogonies at redshift three the matter content of a typical present-day galaxy is dispersed over several individual clumps embedded in sheet-like structures, often aligned along filaments. We have used hydrodynamical…
We present HST/STIS and FUSE spectra of the QSO PG 1211+143 (z_em = 0.081) and a galaxy survey of the surrounding field. This sightline shows two strong intergalactic absorption systems at cz ~ 15,300 and 19,300. This sightline addresses…
The intracluster medium (ICM) in the far outskirts (r $>$ 2-3 R$_{200}$) of galaxy clusters interfaces with the intergalactic medium (IGM) and is theorized to comprise diffuse, multiphase gas. This medium may hold vital clues to clusters'…
A key assumption in quasar absorption line studies of the circumgalactic medium (CGM) is that each absorption component maps to a spatially isolated "cloud" structure that has single valued properties (e.g. density, temperature,…
The Intergalactic Medium (IGM) contains $>$50% of the baryonic mass of the Universe, yet the mechanisms responsible for keeping the IGM ionized has not been fully explained. Hence, we investigate ion abundances from the largest blind QSO…
We have analyzed the properties of metals in the high redshift intergalactic medium using a novel objective pixel optical depth technique on a sample of extremely high signal-to-noise Keck HIRES and ESI spectra of 26 quasars between…
Using hydrodynamic simulations we compute the metal enrichment history of the intergalactic medium (IGM). We show that galactic superwind (GSW) feedback can transport metals to the IGM and that the properties of simulated metal absorbers…
We investigate the absorption structure of the oxygen in the interstellar medium by analyzing {\it XMM}-Newton observations of the low mass X-ray binary Sco X-1. We use simple models based on the O {\sc i} atomic cross section from…