This review briefly discusses the use of UV absorption lines in the spectra of low-redshift QSOs for the study of the physical conditions, metallicity, and baryonic content of the low−z IGM, with emphasis on implications for the missing baryons problem. Current results on the statistics and baryonic content of intervening, low−z O VI and Lyα absorption-line systems are presented with some comme...

We present Chandra observations of two radio-quiet QSOs, PG 2302+029 and PG 1254+047. PG2302+029 has an ultra high-velocity UV absorption system (∼ −56, 000 km s), while PG 1254+047 is a Broad Absorption Line (BAL) QSO with detached troughs. Both objects are X-ray weak, consistent with the known correlation between αox and the strength of the UV absorption lines. The data suggest that there is ...

This talk discusses the unified X-ray/UV absorption models in AGN. I will first review the models and discuss how they offer an unique opportunity to probe the near nuclear environment of AGNs. Recently, however, the validity of these models has been questioned by a number of authors. I will discuss these papers and argue that the data/ models presented in them do NOT contradict the unified X-r...

(Oxy)nitride materials have attractive properties directly related to the role played by nitrogen. A commonly used synthesis method consists of the thermal nitridation of an oxide precursor in flowing ammonia. As a consequence of the anionic N3-/O2substitution results an increase in the covalent character, illustrated by a shift of the absorption edge towards higher wavelength values. Thus, oxy...

We present soft X-ray results from observations with Chandra (HETGS) of the Seyfert I AGN NGC 4593 and Mrk 509. We discuss the photoionized outflows associated with Seyfert I AGN in terms of their absorption spectral signatures and discuss their kinematics, column density and ionization state. We discuss the link between UV and X-ray absorbers in Mrk 509 (which was simultaneously observed with ...

We measure the 2-point correlation function, ξAG, between galaxies and quasar absorption line systems at z < 1, using the dataset of Morris & Jannuzi (2006) on 16 lines-of-sight (LOS) with UV spectroscopy and galaxy multi-object spectroscopy (paper I). The measurements are made in 2D redshift space out to π = 20h Mpc (comoving) along the LOS and out to σ = 2h Mpc projected; as a function of HI ...