Related papers: Companions of Qsos at Redshift 1.1
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 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)…
A preliminary analysis of fields around 20 mainly radio-quiet QSOs (RQQs) at intermediate redshift is summarized. We find overdensities of faint sources around 50% of our observed QSOs suggesting that they are located in groups or even…
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…
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 $22<R\le 23.0$)…
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…
We describe J,H,K deep imaging of 90 arcmin fields around 4 QSOs and one Radio galaxy at redshifts in the range 0.06 to 0.30, and show their images, luminosity profiles, and NIR 2-colour diagrams of objects. We find that the QSO hosts are…
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 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 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 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…
Three high-redshift (z=2) and high luminosity (M_B < -28 mag for Ho = 50, qo=0.5) QSOs, two radio-quiet one radio-loud, were imaged in R, I and K bands. The luminosities, colours and sizes of the hosts overlap with those of actively…
In a pilot search for high-redshift radio QSOs, we have obtained spectra of 55 FIRST sources (S(1.4GHz) > 1 mJy) with very red (O-E > 3) starlike optical identifications. 10 of the candidates are QSOs with redshifts 3.6 < z < 4.4 (4…
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 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 $\lesssim 10…
Results of optical identification of the ASCA Lynx deep survey are presented. Six X-ray sources are detected in the 2-7 keV band using the SIS in a 20'x20' field of view with fluxes larger than ~4x10^{-14} erg s-1 cm-2 in the band.…
We have been conducting an imaging survey to detect host galaxies of radio-quiet QSOs at high redshift (z = 2), in order to compare them with those of radio-loud objects. Six QSOs were observed in the R passband with the auxiliary port of…
X-ray luminous radio-quiet high redshift QSOs are rare and can be used for the investigation of several important astronomical questions. We have conducted a large area survey for radio-quiet high redshift QSOs in the ROSAT All-Sky Survey,…
We obtained spectra of 60 red, starlike objects (E< 18.8) identified with FIRST radio sources, S_{1.4GHz} > 1 mJy. Eight are QSOs with redshift z> 3.6.Combined with our pilot search (Benn et al 2002), our sample of 121 candidates yields a…
We have carried out an investigation of the galaxy environments of low redshift ($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…