相关论文: Environments of QSOs at intermediate redshifts
We have conducted an optical study of the environments of seven radio-loud quasars at redshifts 1<z<1.6. In this paper we describe deep B and R band images obtained for fields of $\sim6\times$6 arcmin around these quasars with 3$\sigma$…
We discuss broad- and narrow-band imaging of 7 arcmin fields of 14 QSOs with redshift ~1.1. The narrow-band filters were chosen to detect redshifted [O II] 3727A, and the broad bands are R and I, which correspond to rest wavelengths…
We outline our recently started program to investigate the galaxy environment of QSOs, in particular of radio-quiet objects at intermediate redshifts.
An angular correlation of low significance (2 sigma) is observed between 0.3 < z < 0.5 QSOs and V < 23 galaxies. Overall, the cross-correlation function between 82 intermediate-redshift (0.3 < z < 0.7), X-ray selected QSOs and V < 24…
Deep $B$ and $R$ band images (R<24 and B<25) have been obtained of a field of $\sim 6 \times 6$ arcmin around seven radio-loud quasars with $1<z<1.6$. A statistically significant excess of faint ($22.5<B\le 23.5$ and $22<R\le 23.0$)…
Luminous high-redshift QSOs are thought to exist within the most massive dark matter haloes in the young Universe. As a consequence they are likely to be markers for biased, over-dense regions where early galaxies cluster, regions that…
In this paper we present results of an analysis of radio-quiet QSO environments. The aim is to determine the relation between QSOs and galaxies as a function of redshift. We cross-correlate a sample of ~150 QSOs from optically and X-ray…
We present submillimetre and mid-infrared imaging observations of five fields centred on quasi-stellar objects (QSOs) at 1.7<z<2.8. All 5 QSOs were detected previously at submillimetre wavelengths. At 850 (450) um we detect 17 (11)…
We have carried out an investigation of the galaxy environments of low redshift ($z<0.3$) QSOs by cross-correlating the positions on the sky of X-ray-selected QSOs/AGN identified in the {\it Einstein} Medium Sensitivity Survey (EMSS) with…
We present the results of an infrared survey of QSO fields at z=0.95, 0.995 and 1.5. Each z<1 field was imaged to typical continuum limits of J=20.5, Kprime=19 (5 sigma), and line fluxes of 1.3E10{-16}ergs/cm^2/s (1 sigma)in a 1%…
We analyse new deep g and i-band imaging with the CFHT of 16 QSOs in the redshift range 0.9 to 1.3. The principal points of interest are the symmetry and signs of tidal effects in the QSO hosts and nearby (`companion') galaxies. The sample…
We report on a wide-area (48' x 9') imaging survey of faint galaxies in R and I bands toward the 1338+27 field where an unusual concentration of five QSOs at z\sim1.1, embedded in a larger-scale clustering of 23 QSOs, is known to exist.…
X-ray luminous radio-quiet high redshift QSOs are rare and can be used for the investigation of several important astronomical questions. We have conducted a large area survey for radio-quiet high redshift QSOs in the ROSAT All-Sky Survey,…
We report the first detection of emission line gas within the host galaxies of high redshift QSOs. This was done using narrow-band imaging at the redshifted wavelengths of [O III] and H alpha, using the PUEO adaptive optics camera of the…
It is shown that all of the 32 point X-ray sources which lie within about 10' of the centre of nearby galaxies, and which have so far been optically identified are high redshift objects - AGN or QSOs. Thus the surface density of these QSOs…
We review previous results on the clustering and environments of QSOs. We show that the correlation length for QSOs derived from existing surveys is r~5/h Mpc, similar to the observed correlation length for field galaxies at the present…
We discuss 6 GHz JVLA observations covering a volume-limited sample of 178 low redshift ($0.2 < z < 0.3$) optically selected QSOs. Our 176 radio detections fall into two clear categories: (1) About $20$\% are radio-loud QSOs (RLQs) having…
Images are discussed of six QSOs at z=2.3, one QSO-like IRAS source at z=2.3, and one QSO at z=1.1, taken with resolution 0.6 to 0.9 arcsec. Five of the QSOs are radio-quiet. All QSOs except one are just resolved, while the IRAS source has…
Observed high-redshift QSOs, at z~6, may reside in massive dark matter (DM) halos of more than 10^{12} Msun and are thus expected to be surrounded by overdense regions. In a series of 10 constrained simulations, we have tested the…
We test the hypothesis whether high redshift QSOs would preferentially appear in small groups or pairs, and if they are associated with massive, young clusters. We carried out a photometric search for \Ly emitters on scales $\lesssim 10…