相关论文: The Form and Evolution of the Clustering of QSO He…

We have analyzed the clustering of C IV and Mg II absorption-line systems on comoving scales from 1 to 16 \hMpc, using an extensive catalog of heavy-element QSO absorbers with mean redshift 2.2 (C IV) and 0.9 (Mg II). For the C IV sample as…

We have analyzed the clustering of C IV absorption line systems in an extensive new catalog of heavy element QSO absorbers. The catalog permits exploration of clustering over a large range in both scale (from about 1 to over 300 Mpc) and…

We examine the line-of-sight clustering of QSO heavy-element absorption-line systems, using a new measure of clustering, called the reduced second moment measure, that directly measures the mean over-density of absorbers. While closely…

We study clustering on very large scales -- from several tens to hundreds of comoving Mpc -- using an extensive catalog of heavy-element QSO absorption-line systems. We find significant evidence that C IV absorbers are clustered on comoving…

We examine the three-dimensional clustering of C IV absorption-line systems, using an extensive catalog of QSO heavy-element absorbers drawn from the literature. We measure clustering by a volume-weighted integral of the correlation…

In Keck HIRES spectra of 9 QSOs we identify a sample of 908 CIV absorber components in 188 systems outside the Lyman forest in the redshift range 1.6 < z < 4.4, with related lines of SiIV, CII, SiII and NV. The properties of the CIV…

Using Voigt-profile-fitting procedures on Keck HIRES spectra of nine QSOs we identify 1099 CIV absorber components clumped in 201 systems outside the Lyman forest over 1.6 < z < 4.4. With associated SiIV, CII, SiII and NV where available we…

We have made a statistically complete, unbiased survey of C IV systems toward a region of high QSO density near the South Galactic Pole using 25 lines of sight spanning $1.5<z<2.8$. Such a survey makes an excellent probe of large-scale…

Using data from the Sloan Digital Sky Survey data release 3 (SDSS DR3) we investigate how narrow (<700km/s) CIV and MgII quasar absorption line systems are distributed around quasars. The CIV absorbers lie in the redshift range 1.6 < z < 4…

We present a high signal-to-noise high resolution spectrum of the radio-quiet QSO HS1700+6416 (z = 2.72). Analysis of the absorption line systems with metals yields the following results. (1) The dense cluster of C IV doublets at 2.432 <…

To investigate the evolution of metal-enriched gas over recent cosmic epochs as well as to characterize the diffuse, ionized, metal-enriched circumgalactic medium (CGM), we have conducted a blind survey for C IV absorption systems in 89 QSO…

We report on the statistics of strong (W_r > 0.15 A) C IV absorbers at z=1.5-3.5 toward high-redshift gamma-ray bursts (GRBs). In contrast with a recent survey for strong Mg II absorption systems at z < 2, we find that the number of C IV…

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,…

We report the detection of a significant clustering signal on scales $\Delta v < 300$ km/s, for a sample of 71 C IV absorbers. This result confirms previous findings and, together with data at lower column density, it points to a trend of…

We aim to study the clustering of metal absorption lines and the structures that they arise in as a function of cosmic time. We focus on C IV and Si IV absorption features that are identified along a given quasar sightline. We exploit the…

We present a clustering analysis of QSOs over the redshift range z=0.3-2.9. We use a sample of 10558 QSOs taken from the preliminary catalogue of the 2dF QSO Redshift Survey (2QZ). The two-point redshift-space correlation function of QSOs…

We use a halo occupation approach to connect MgII absorbers to dark matter halos as a function of redshift. Using the model constructed in Tinker & Chen (2008), we parameterize the conditional probability of an absorber of equivalent width…

With close pairs of quasars at different redshifts, a background quasar sightline can be used to study a foreground quasar's environment in absorption. We used a sample of 17 Lyman limit systems with column density N_HI > 10^19 cm^-2…

We have compiled a new and extensive catalog of heavy-element QSO absorption line systems and analyzed the distribution of absorbers in bright and faint QSOs, to search for gravitational lensing of background QSOs by the matter associated…

We use new observations of very weak CIV absorption lines associated with high-redshift Lyman-alpha absorption systems to measure the high-redshift Lyman-alpha line two-point correlation function (TPCF). These very weak CIV absorption lines…