A Large Quasar Group (LQG) of particularly large size and high membership has been identified in the DR7QSO catalogue of the Sloan Digital Sky Survey. It has characteristic size (volume 1/3 ) ∼ 500 Mpc (proper size, present epoch), longest dimension ∼ 1240 Mpc, membership of 73 quasars, and mean redshiftz = 1.27. In terms of both size and membership it is the most extreme LQG found in the DR7QSO catalogue for the redshift range 1.0 z 1.8 of our current investigation. Its location on the sky is ∼ 8.8 • north (∼ 615 Mpc projected) of the Clowes & Campusano LQG at the same redshift,z = 1.28, which is itself one of the more extreme examples. Their boundaries approach to within ∼ 2 • (∼ 140 Mpc projected). This new, huge LQG appears to be the largest structure currently known in the early universe. Its size suggests incompatibility with the Yadav et al. scale of homogeneity for the concordance cosmology, and thus challenges the assumption of the cosmological principle.

The Clowes & Campusano large quasar group (LQG) atz = 1.28 has been re-examined using the quasar data from the DR7QSO catalogue of the Sloan Digital Sky Survey. In the 1991 discovery, the LQG impinged on the northern, southern and eastern limits of the survey. In the DR7QSO data, the western, northern and southern boundaries of the LQG remain essentially the same, but an extension eastwards of ∼2 • is indicated. In the DR7QSO data, the LQG has 34 members, withz = 1.28. A new group of 38 members is indicated atz = 1.11 and within ∼2. • 0 of the Clowes & Campusano LQG. The characteristic sizes of these two LQGs, ∼350-400 Mpc, appear to be only marginally consistent with the scale of homogeneity in the concordance cosmology. In addition to their intrinsic interest, these two LQGs provide locations in which to investigate early large-scale structure in galaxies and to identify high-z clusters. A method is presented for assessing the statistical significance and overdensity of groups found by linkage of points.

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We report the discovery of an unusual quasar, 2226-3905, found during a survey of quasar candidates. The ultraviolet spectrum (intrinsic frame) of the object is dominated by extremely strong Fe II emission. The emission lines are narrow (typical FWHM-2150 km S-1) a!ld show little trac~ of their usually broad wings. C III] A, 1909 appears t~ be blended w1th an Fe III multtplet and we identify Fe II lines originating from ~1gh-ene~gy ~ev~ls (-10 eV). We c~nsi~er two possible explanations: either the quasar 1S a .low-10mzatton broad absorption lme (BAL) quasar in which the sight-line does ~ot mtersect ~ny BAL clouds or Lyoc fluorescence is the main physical process involved m the format10n of Fe II. Our observations do not favour the BAL interpretation, but rather support the latter process. Higher resolution observations would give definite support to the Lyoc fluorescence.

We look at quasar environment in the context of large‐scale structure (LSS) – a new approach, giving a more informed interpretation of quasar–galaxy correlations. This paper presents our first results for a sample of z∼0.3 quasars. We use Voronoi tessellation applied in colour (BJ‐R) slices for the detection of galaxy clusters and the minimal spanning tree (MST) to delineate the large‐scale structure. This new cluster detection method allows us to find reliably galaxy clusters at z<0.3 from SuperCOSMOS measurements of UK Schmidt Telescope plates. By reconstructing the large‐scale structure in a relatively narrow redshift band (0.2