The environments of intermediate-redshift QSOs: 0.3 < z < 0.7 |
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| Authors: | R J Smith B J Boyle S J Maddox |
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| Institution: | Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA; Research School of Astronomy and Astrophysics, Mount Stromlo Observatory, Institute of Advanced Studies, Australian National University, Private bag, Weston Creek PO, ACT 2611, Australia; Anglo-Australian Observatory, PO Box 296, Epping, NSW 2121, Australia; School of Physics &Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD |
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| Abstract: | An angular correlation of low significance (2 σ ) 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 galaxies is investigated, but no signal is detected for the z >0.5 QSOs. After converting to an excess of galaxies physically associated with the QSO, this lack of strong correlation is shown to be consistent with the clustering of normal galaxies at the same moderate redshifts. Combined with previous observations, these results imply that the environments of radio-quiet QSOs do not undergo significant evolution with respect to the galaxy population over a wide range of redshifts (0< z <1.5). This is in marked contrast to the rapid increase in the richness of the environments associated with radio-loud QSOs over the same redshift range. |
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| Keywords: | galaxies: active galaxies: clusters: general quasars: general |
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