Related papers: Quasar environments at 0.5 < z < 0.8
We have conducted a NIR study of the environments of seven radio-loud quasars at redshifts 1<z<1.6. In present paper we describe deep $K$ band images obtained for the fields of ~6X6 arcmin around the quasars with 3$\sigma$ limiting…
We use optical and near-IR imaging to examine the properties of the significant excess population of K>=19 galaxies found in the fields of 31 z=1-2 radio-loud quasars by Hall, Green & Cohen (1998). The excess occurs on two spatial scales: a…
Observations with the Wide-Field Camera of the Hubble Space Telescope are presented for a representative sample of 20 intrinsically luminous quasars with redshifts smaller than 0.30. These observations show that luminous quasars occur in…
We present VLT/ISAAC near-infrared imaging of the host galaxies of 15 low luminosity quasars at 1 < z < 2. This work complements our studies to trace the cosmological evolution of the host galaxies of high luminosity quasars. The radio-loud…
We investigate the group-scale environment of 15 luminous quasars (luminosity $L_{\rm 3000}>10^{46}$ erg s$^{-1}$) from the Cosmic Ultraviolet Baryon Survey (CUBS) at redshift $z\approx1$. Using the Multi Unit Spectroscopic Explorer (MUSE)…
Submillimeter (and in some cases millimeter) wavelength continuum measurements are presented for a sample of 40 active galactic nuclei (probably all quasars) lensed by foreground galaxies. The object of this study is to use the lensing…
We examine the clustering of galaxies around a sample of 20 luminous low redshift (z<0.30) quasars observed with the Wide Field Camera-2 on the Hubble Space Telescope. The HST resolution makes possible galaxy identification brighter than…
We study the radio properties of moderately obscured quasars over a range of redshifts to understand the role of radio activity in accretion using the Jansky Very Large Array (JVLA) at 6.0GHz and 1.4GHz. Our z~2.5 sample consists of…
We present an analysis of a large sample of AGN environments at z~1 using stacked Spitzer data at 3.6um. The sample contains type-1 and type-2 AGN in the form of quasars and radio galaxies, and spans a large range in both optical and radio…
In this thesis, I present an investigation into the environments of quasars with respect to galaxy clusters, and environment evolution with redshift and luminosity. The orientation of the quasar with respect to the major axis of the closest…
We present high spatial resolution near-infrared H-band (1.65 microns) images, taken with ISAAC on UT1 of ESO VLT, of three radio-loud quasars at z = 1.5, as a pilot study for imaging of a larger sample of radio-loud and radio-quiet quasars…
Radio-loud Active Galactic Nuclei at z~2-4 are typically located in dense environments and their host galaxies are among the most massive systems at those redshifts, providing key insights for galaxy evolution. Finding radio-loud quasars at…
We report the first results from the Clusters Around Radio-Loud AGN (CARLA) program, a Cycle 7 and 8 Spitzer Space Telescope snapshot program to investigate the environments of a large sample of obscured and unobscured luminous radio-loud…
Using the Spitzer Space Telescope, we have obtained 3.6--24 micron photometry of 38 radio galaxies and 24 quasars from the 3CR catalog at redshift 1<z<2.5. This 178 MHz-selected sample is unbiased with respect to orientation and therefore…
A sample of 16 quasars selected from the Large Bright Quasar Survey in the redshift range 0.4 < z < 0.5 has been imaged in the R band with the Planetary Camera on the WFPC2 instrument of the Hubble Space Telescope. The host galaxy…
Measuring the environments of massive galaxies at high redshift is crucial to understanding galaxy evolution and the conditions that gave rise to the distribution of matter we see in the Universe today. While high-$z$ radio galaxies…
We present near-infrared imaging with ESO VLT+ISAAC of the host galaxies of low luminosity quasars in the redshift range 1 < z < 2, aimed at investigating the relationship between the nuclear and host galaxy luminosities at high redshift.…
We have made radio observations of 87 optically selected quasars at 5 GHz with the VLA in order to measure the radio power for these objects and hence determine how the fraction of radio-loud quasars varies with redshift and optical…
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 Hubble Space Telescope (HST) Wide Field Planetary Camera 2 (WFPC2) data on the large-scale environments of 16 0.39 < z < 0.51 quasars from the Large Bright Quasar Survey (LBQS). The LBQS quasars are representative of the…