相关论文: Narrow absorption lines with two observations of S…

We report the detection of a zabs=0.3654 associated absorption-line system in the UV spectrum of the CSS quasar 3C48. The absorbing material is blue shifted with respect to the quasar emission-line redshift, zem=0.3700, suggesting an…

Broad absorption lines (BALs) in quasar spectra are prominent signatures of high-velocity outflows, which might be present in all quasars and could be a major contributor to feedback to galaxy evolution. Studying the variability in these…

We carried out a Subaru and UKIRT near infrared imaging survey for H-alpha emitting galaxies around two pair quasar systems (Q0301-005/Q0302-003 and Q2343+125/Q2344+125), and a triple quasar system (KP76/KP77/KP78). Narrow band near…

We present a search for metal absorption line systems at the highest redshifts to date using a deep (30h) VLT/X-Shooter spectrum of the z = 7.084 quasi-stellar object (QSO) ULAS J1120+0641. We detect seven intervening systems at z > 5.5,…

[Abridged] We present 23 quasar absorption line systems selected by the MgII doublet with W_r(2796)>0.3 Ang over the redshift range 0.4<z<1.2. The kinematics are studied at ~6 km/s resolution to a 5-sigma detection threshold of 0.015 Ang.…

We report the discovery of rapid variations of a high-velocity Mg ii broad absorption line (BAL) trough in the quasar SDSS J133356.02+001229.1 (zem ~ 0.9197). Vivek et al. (2012a) revealed the emergence and subsequent near disappearance of…

The z=0.9902 system along the quasar PG 1634+706 line of sight is a strong MgII absorber (W(2796)>0.3A) with only weak CIV absorption (it is ``CIV-deficient''). To study this system, we used high-resolution spectra from both HST/STIS…

We present nebular emission associated with 198 strong Mg II absorbers at 0.35 $\le z \le$ 1.1 in the fibre spectra of quasars from the Sloan Digital Sky Survey. Measured [O II] luminosities (L$_{[O II]}$) are typical of sub-L$^{\star}$…

The incidence rate of Mg II absorbers per unit redshift path (dN/dz) towards quasar sightlines has been used to probe the interaction between quasar jets and surrounding gas clouds. Studies using core- and lobe-dominated samples found a…

The study of high-redshift bright quasars is crucial to gather information about the history of galaxy assembly and evolution. Variability analyses can provide useful data on the physics of the quasar processes and their relation with the…

We performed spectroscopic observations of the small-separation lensed quasar SDSS J1001+5027, whose images have an angular separation $\theta \sim 2.^{\!\!\prime\prime}86$, and placed constraints on the physical properties of gas clouds in…

Broad absorption lines (BALs) in quasar spectra identify high velocity outflows that likely exist in all quasars and could play a major role in feedback to galaxy evolution. The variability of BALs can help us understand the structure,…

We present initial results from the first systematic survey for MgII quasar absorption lines at z > 2.5. Using infrared spectra of 46 high-redshift quasars, we discovered 111 MgII systems over a path covering 1.9 < z < 6.3. Five systems…

First results from a study of high ionization absorption properties in roughly 30 Mg II absorption selected galaxies are presented. We have tested for correlations of Mg II, C IV, Si IV, N V, and O VI equivalent widths with the galaxy…

A few percent of quasars show strong associated MgII absorption, with velocities (v_off) lying within a few thousand km/s from the quasar systemic redshift. These associated absorption line systems (AALs) are usually interpreted as…

We report the detection of OVI 1031,1037 and NV 1238,1242 absorption in a system of "mini-broad" absorption lines (mini-BALs) previously reported to have variable CIV 1548,1550 in the quasar PG0935+417. The formation of these lines in an…

We present a time-variability analysis of 29 broad absorption line quasars (BALQSOs) observed in two epochs by the Sloan Digital Sky Survey (SDSS). These spectra are selected from a larger sample of BALQSOs with multiple observations by…

We present 21 examples of C IV Broad Absorption Line (BAL) trough disappearance in 19 quasars selected from systematic multi-epoch observations of 582 bright BAL quasars (1.9 < z < 4.5) by the Sloan Digital Sky Survey-I/II (SDSS-I/II) and…

We present observations of probable line-of-sight acceleration of a broad absorption trough of C IV in the quasar SDSS J024221.87+004912.6. We also discuss how the velocity overlap of two other outflowing systems in the same object…

We present a catalog of intervening MgII quasar absorption-line systems in the redshift interval 0.36 <= z <= 2.28. The catalog was built from Sloan Digital Sky Survey Data Release Four (SDSS DR4) quasar spectra. Currently, the catalog…