THE<i>SPITZER</i>EXTRAGALACTIC REPRESENTATIVE VOLUME SURVEY: THE ENVIRONMENTS OF HIGH-<i>z</i>SDSS QUASI-STELLAR OBJECTS

Abstract

This paper presents a study of the environments of SDSS Quasi-Stellar-Objects\n(QSOs) in the Spitzer Extragalactic Representative Volume Survey (SERVS). We\nconcentrate on the high-redshift QSOs as these have not been studied in large\nnumbers with data of this depth before. We use the IRAC 3.6-4.5{\\mu}m colour of\nobjects and ancillary r-band data to filter out as much foreground\ncontamination as possible. This technique allows us to find a significant (&gt;\n4-{\\sigma}) over-density of galaxies around QSOs in a redshift bin centred on z\n~ 2.0 and a (&gt; 2-{\\sigma}) over-density of galaxies around QSOs in a redshift\nbin centred on z ~ 3.3. We compare our findings to the predictions of a\nsemi-analytic galaxy formation model, based on the {\\Lambda}CDM millennium\nsimulation, and find for both redshift bins that the model predictions match\nwell the source-density we have measured from the SERVS data.\n