Related papers: High resolution study of associated C IV absorptio…

The C IV doublet in the UV has long been associated with accretion in T Tauri stars. However, it is still unclear where and how the lines are formed. Here, we present a new C IV line model based on the currently available accretion shock…

We study the transverse clustering properties of high matter density peaks as traced by high column density absorption systems (either Lyman limit systems characterized by N(HI)> 2 x 10^{17} cm^{-2} or CIV systems with W_{r}> 0.5 A) at…

We present high resolution (R = 114,000) ultraviolet measurements of the interstellar absorption line profiles of the CIV (1550 A) high ionization doublet recorded towards the nearby B2Ve star HD 158427 (d~74pc). These data, which were…

In this paper, we report on two C IV narrow absorption systems emerging from the spectrum of the quasar SDSS J095254.10 +021932.8, which are located at $z_{\rm abs}=2.0053$ and $z_{\rm abs}=1.8011$, respectively. These features have…

We present spectra of QSOs 1343+266 A B, covering Ly-beta to C~IV emission at 2\AA~resolution, and find further evidence that this system is not gravitationally lensed. We see, however, a large number of Ly-alpha and some C~IV absorption…

Results of a careful analysis of the highly ionized absorption systems, observed over the redshift range 2.198--2.2215 in the zem=2.24 HDFS-QSO J2233-606, are presented. Strong OVI and NeVIII absorptions are detected. Most of the lines show…

The size and mass of two circum-galactic medium (CGM) clouds in the halo (impact parameter = 65 kpc) of a nearby late-type galaxy, MGC-01-04-005 ($cz = 1865$ km/s), are investigated using a close triplet of QSO sight lines (the "LBQS…

We present HST STIS observations of four quasar pairs with redshifts 0.84<z_em<1.56 and angular separation 2-3 arcmin corresponding to ~ 1-1.5 h^-1_50 Mpc transverse proper distance at z ~ 0.9. We study the distribution of velocity…

We present both phenomenological and more physical photoionization models of the Chandra HETG spectra of the Seyfert-1 AGN NGC 4051. We detect 40 absorption and emission lines, encompassing highly ionized charge states from O, Ne, Mg, Si, S…

Associated absorption lines (AALs) in quasar spectra are valuable probes of the gas kinematics and physical conditions in quasar environments. The host galaxies are by definition in an active evolution stage that might involve large-scale…

We report the discovery of two damped Ly-alpha absorption-line systems (DLAs) near redshift z=1 along a single quasar sightline (Q1727+5302) with neutral hydrogen column densities of N(HI) = (1.45\pm0.15)\times10^{21} and…

(Abridged) Our deep multiwavelength campaign on NGC 5548 revealed an unusually strong X-ray obscuration. The resulting dramatic decrease in incident ionizing flux allowed us to construct a comprehensive physical, spatial and temporal…

We present VLT/UVES spectroscopy of the quasar Q0841+129, whose spectrum shows a proximate damped Lyman-alpha (PDLA) absorber at z=2.47621 and a proximate sub-DLA at z=2.50620, both lying close in redshift to the QSO itself at…

During an extensive multiwavelength campaign that we performed in 2013-14 the prototypical Seyfert 1 galaxy NGC 5548 has been found in an unusual condition of heavy and persistent obscuration. The newly discovered "obscurer" absorbs most of…

We present the results of ALMA observations in $^{12}$CO($J=2-1$), $^{13}$CO($J=2-1$), and C$^{18}$O($J=2-1$) lines and 1.3 mm continuum emission toward a massive ($\sim 10^6 M_{\odot}$) giant molecular cloud associated with the giant H II…

We report on the analysis of a multiphase Lyman limit system (LLS) at $z=0.39047$ identified towards the background quasar FBQS J0209-0438. The O VI doublet lines associated with this absorber have a different profile from the low…

(Abridged) The archetypal Seyfert 1 galaxy NGC 5548 was observed in 2013-2014 in the context of an extensive multiwavelength campaign, which revealed the source to be in an extraordinary state of persistent heavy obscuration. We re-analyzed…

We report the detection of highly-ionized gas at z~0 seen in resonant UV and X-ray absorption lines toward the z=0.03 blazar Mkn 421. A total of 13 X-ray and 3 UV lines were measured (or upper limits derived), including three lines in the…

We report ultraviolet spectra of Galactic high-velocity clouds (HVCs) in Complex C, taken by the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope (HST), together with new 21-cm spectra from the Green Bank Telescope. The wide…

We present the detection and analysis of a weak low-ionization absorber at $z = 0.12122$ along the blazar sightline PG~$1424+240$, using spectroscopic data from both $HST$/COS and STIS. The absorber is a weak Mg II analogue, with incidence…