Related papers: Lost Baryons at Low Redshift
We discuss physical properties and baryonic content of broad Ly alpha absorbers (BLAs) at low redshift. These absorption systems, recently discovered in high-resolution, high-signal to noise quasar absorption line spectra, possibly trace…
A soft X-ray excess has been claimed to exist in and around a number of galaxy clusters and this emission has been attributed to the warm-hot intergalactic medium that may constitute most of the baryons in the local universe. We have…
The missing baryon problem may now be resolved, but the exact location and physical properties of the diffuse component remains unclear. This problem could be tractable, but requires the combination of new galaxy redshift surveys with new…
This paper presents an analysis of XMM X--ray spectra of the quasar 1ES 1553+113, in search for absorption lines from the intervening warm--hot intergalactic medium. A search for OVII, OVIII and NeIX resonance absorption lines was performed…
At redshifts z >~ 2, most of the baryons reside in the smooth intergalactic medium which is responsible for the low column density Lyman-alpha forest. This photoheated gas follows a tight temperature-density relation which introduces a…
The intergalactic medium (IGM) is the dominant reservoir of baryons at all cosmic epochs. We investigate the evolution of the IGM from z=2-0 in 48 Mpc/h, 110-million particle cosmological hydrodynamic simulations using three prescriptions…
We describe an extensive FUSE survey of highly ionized oxygen in the vicinity of the Milky Way that serves as an example of the type of study that would be desirable for other galactic systems. Understanding the origin of hot gas in the…
We present an analysis of the Lyman alpha forests of five quasar spectra in the near UV. Properties of the intergalactic medium (IGM) at an intermediate redshift interval (0.9 < z < 1.9) are studied. The amount of baryons in the diffuse…
The relation between high redshift galaxies and QSO absorption systems is discussed in the context of hierarchical galaxy formation. It is demonstrated that imprints of the reionization history of the universe are detectable in the…
Most of the baryons in the low-redshift universe reside in a warm/hot component which is difficult to detect with standard absorption/emission line techniques. We propose to use quasar refractive scintillation as an useful, complementary…
Observations of the cosmic microwave background indicate that baryons account for 5% of the Universe's total energy content. In the local Universe, the census of all observed baryons falls short of this estimate by a factor of two.…
We present an analysis of the large-scale galaxy distribution around two possible warm-hot intergalactic medium (WHIM) absorption systems reported along the Markarian 421 sightline. Using the Sloan Digital Sky Survey, we find a prominent…
The relationship between galaxies and the state/chemical enrichment of the warm-hot intergalactic medium (WHIM) expected to dominate the baryon budget at low-z provides sensitive constraints on structure formation and galaxy evolution…
The backbone of the large-scale structure of the Universe is determined by processes on a cosmological scale and by the gravitational interaction of the dominant dark matter. However, the mobile baryon population shapes the appearance of…
In this contribution, I review the current observational evidence for the existence of filaments of Warm-Hot Intergalactic Medium (WHIM). In particular, I first focus on the controversial issue of the identification of the $z\sim 0$ highly…
We present a high resolution (R~500) X-ray spectrum of the bright quasar H1821+643 (z=0.297), obtained in a 470 ksec Chandra observation. We search for X-ray absorption by highly ionized metal species, OVII and OVIII in particular, at the…
We expand on the recently reported detections of the gamma-ray resonant absorption along the line of sight toward gamma-ray bright quasars (QSOs), like 3C279. We propose to use this novel gamma-ray absorption method to study the Dark Matter…
In recent years, the autocorrelation of the hydrogen Lyman-{\alpha} forest has been used to observe the baryon acoustic peak at redshift 2 < z < 3.5 using tens of thousands of QSO spectra from the BOSS survey. However, the interstellar…
This thesis explores the missing baryon problem in a computational context. An overview of the problem is given, along with a discussion regarding the relevance of the Circumgalactic Medium (CMG) and cosmological Zoom-in simulations. The…
In a $\Lambda$CDM cosmology, galaxy formation is a globally inefficient process: it is often the case that far fewer baryons are observed in galaxy disks than expected from the cosmic baryon fraction. The location of these "missing baryons"…