Related papers: Missing Baryons in the Warm-Hot Intergalactic Medi…
We create stacked composite absorption spectra from Hubble Space Telescope Faint Object Spectrograph data from four quasi-stellar objects to search for absorption lines in the extreme ultraviolet wavelength region associated with LyA forest…
Ultraviolet spectrographs aboard the Hubble Space Telescope (HST) and the Far Ultraviolet Spectroscopic Explorer (FUSE) have proved their value as sensitive probes of the low-density intergalactic medium (IGM) at low redshifts (z < 0.1).…
We present results from an analysis of FUSE and HST/STIS spectroscopy of the z_em=0.57 quasar PKS0405-123. We focus on the intervening metal-line systems identified along the sightline and investigate their ionization mechanism, ionization…
We present an ultraviolet spectroscopic survey of strong H I absorbers in the intergalactic medium, probing their evolution over the last 6-7 Gyr at redshifts $0.24 \leq z \leq 0.84$. We measure column densities $N_{\rm HI} \,( {\rm…
The spectrum of the low-redshift QSO PG0953+415 shows two strong, intervening O VI absorption systems. To study the nature of these absorbers, we have used the Gemini Multiobject Spectrograph to conduct a deep spectroscopic galaxy redshift…
The cosmological missing baryons at z<1 most likely hide in the hot (T$\gtrsim10^{5.5}$ K) phase of the Warm Hot Intergalactic Medium (WHIM). While the hot WHIM is hard to detect due to its high ionisation level, the warm…
High signal-to-noise (S/N) observations of the QSO PKS 0405-123 (zem = 0.572) with the Cosmic Origins Spectrograph from 1134 to 1796 A with a resolution of 17 km s-1 are used to study the multi-phase partial Lyman limit system (LLS) at z =…
Using $HST$/COS observations of the twin quasar lines of sight Q$0107-025$A $\&$ Q$0107-025$B, we report on the physical properties, chemical abundances and transverse sizes of gas in a multiple galaxy environment at $z = 0.399$ across a…
We investigate the relationship between galaxies and metal-line absorption systems in a large-scale cosmological simulation with galaxy formation. Our detailed treatment of metal enrichment and non-equilibrium calculation of oxygen species…
We have initiated a survey of MgII 2796, 2803 absorbers near known galaxies at projected distances rho<~100 h^-1 kpc to a background QSO, in order to constrain the extent and covering fraction of Mg^+ ions around galaxies of different…
We study the high-ionization phase and kinematics of the circumgalactic medium around low-redshift galaxies using a sample of 23 Lyman Limit Systems (LLSs) at 0.08<z<0.93 observed with the Cosmic Origins Spectrograph onboard the Hubble…
We have conducted a systematic survey for intervening OVI absorbers in available echelle spectra of 16 QSOs at z_QSO = 0.17-0.57. These spectra were obtained using HST/STIS with the E140M grating. Our search uncovered a total of 27…
We present an analysis of the galaxy environment and physical properties of a partial Lyman limit system at z = 0.83718 with HI and metal line components closely separated in redshift space ($|\Delta v| \approx 400$ km/s) towards the…
Thermally-broadened Lya absorbers (BLAs) offer an alternate method to using highly-ionized metal absorbers (OVI, OVII, etc.) to probe the warm-hot intergalactic medium (WHIM, T=10^5-10^7 K). Until now, WHIM surveys via BLAs have been no…
Most of cosmic baryons predicted by the big-bang nucleosynthesis has evaded the direct detection. Recent numerical simulations indicate that approximately 30 to 50 percent of the total baryons in the present universe is supposed to take a…
We review the current high-significance X-ray detections of Warm-Hot Intergalactic Medium (WHIM) filaments at z>0 along the lines of sight to the two blazars Mrk 421 (z=0.03) and 1ES 1028+511 (z=0.361). For these WHIM filaments, we derive…
We have analysed a large data set of OVI absorber candidates found in the spectra of 3702 SDSS quasars, focusing on a subsample of 387 AGN sightlines with an average S/N>5.0, allowing for detection of absorbers above rest-frame equivalents…
(Abridged) We present a systematic investigation of physical conditions and elemental abundances in four optically thick Lyman-limit systems (LLSs) at $z=0.36-0.6$ discovered within the Cosmic Ultraviolet Baryon Survey (CUBS). CUBS LLSs…
In Paper I of this series (astro-ph/9911117) we described observations of 15 extragalactic targets taken with the Hubble Space Telescope GHRS/G160M grating for studies of the low-z Lya forest. We reported the detection of 110 Lya absorbers…
We present a new method for probing the physical conditions and metal enrichment of the Intergalactic Medium: the composite spectrum of Ly-alpha forest absorbers. We apply this technique to a sample of 9480 Ly-alpha absorbers with redshift…