Related papers: Probing Cosmology with the X-ray Forest
We present a detailed analysis of the galaxy and group distributions around three reported X-ray absorption line systems in the spectrum of the quasar H2356-309. Previous studies associated these absorbers with known large-scale galaxy…
We have measured the distribution function of the flux decrement caused by Lyman alpha forest absorption in a new sample of high resolution QSO spectra. The observations are compared to the results from two simulations of the Lya forest: an…
Simulations predict that shocks from large-scale structure formation and galactic winds have reduced the fraction of baryons in the warm, photoionized phase (the Lya forest) from nearly 100% in the early universe to less than 50% today.…
The intergalactic neutral hydrogen which is responsible for the Lyman alpha forest of quasar absorption is a tracer of much larger amounts of ionised hydrogen. The ionised component has yet to be detected directly, but is expected to…
Hydrodynamic simulations of growth of cosmic structure suggest that 30-50% of the total baryons at z=0 may be in a warm-hot intergalactic medium (WHIM) with temperatures ~10^5-10^7K. The O VI \lambda \lambda 1032, 1038 absorption line…
The warm-hot intergalactic medium (WHIM) at temperatures 1E5-1E7 K is believed to contain 30-50% of the baryons in the local universe. However, all current X-ray detections of the WHIM at redshifts z>0 are of low statistical significance…
This paper presents initial results of a systematic search for resonance X-ray absorption lines from H-like O VIII and He-like O VII caused by the intervening warm-hot intergalactic medium (WHIM). The search is based on far ultra-violet…
The baryon fraction in galaxy clusters is one of the most direct way to constrain $\omo$. The baryonic fraction is estimated to be in the range fb = (0.15 - 0 .20) h^{-3/2} which is several times higher than expected from the observed light…
More than three quarters of the baryonic content of the Universe resides in a highly diffuse state that is difficult to observe, with only a small fraction directly observed in galaxies and galaxy clusters. Censuses of the nearby Universe…
Several popular cosmological models predict that most of the baryonic mass in the local universe is located in filamentary and sheet-like structures associated with galaxy overdensities. This gas is expected to be gravitationally heated to…
We present a detailed study of X-ray absorption in the local interstellar medium by analyzing the X-ray spectra of 24 galactic sources obtained with the {\it Chandra} High Energy Transmission Grating Spectrometer and the {\it XMM-Newton}…
Using the full, three-dimensional potential of galaxy cluster halos (drawn from an N-body simulation of the current, most favored cosmology), the distribution of the X-ray emitting gas is found by assuming a polytropic equation of state and…
In this paper we review the current predictions of numerical simulations for the origin and observability of the warm hot intergalactic medium (WHIM), the diffuse gas that contains up to 50 per cent of the baryons at z~0. During structure…
We derive analytic lower bounds on the cosmic baryon density by requiring that the high-redshift IGM contain enough neutral hydrogen to produce the observed \lya absorption in quasar spectra. The key theoretical assumption is that absorbing…
The Circumgalactic Medium (CGM) of late-type galaxies is characterized using UV spectroscopy of 11 targeted QSO/galaxy pairs at z < 0.02 with the Hubble Space Telescope Cosmic Origins Spectrograph and ~60 serendipitous absorber/galaxy pairs…
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…
We present the baryon fractions of 2MASS groups and clusters as a function of cluster richness using total and gas masses measured from stacked ROSAT X-ray data and stellar masses estimated from the infrared galaxy catalogs. We detect X-ray…
We present a comprehensive analysis of the X-ray observations obtained from \xmm\, and \chandra\, for a sample of bona-fide Compact Symmetric Objects (CSOs) to investigate their X-ray emission properties. Ultimately, we obtain 32 effective…
We analyze the low-redshift (z~0.2) circumgalactic medium by comparing absorption-line data from the COS-Halos Survey to absorption around a matched galaxy sample from two cosmological hydrodynamic simulations. The models include different…
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…