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
(volume1/3)∼ 500 Mpc (proper size, present epoch), longest dimension∼ 1240 Mpc …

We describe a graph theoretical method, using the minimal spanning tree (MST), for finding
candidates for quasar superstructures in quasar surveys. The morphology of the candidate
can be characterized by the normalized mean, m, and normalized standard deviation, σ, of …

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) and …

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 …

We have found evidence for a large, elongated group of at least ten quasars with largest
dimension Mpc at z~ 1.3, in the direction of ESO/SERC field 927, which has the field centre
(1950) There are probably further members that have not yet been observed. The …

The large quasar group (LQG) at 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 …

We present the spectroscopic observations of 56 quasars that were discovered by AQD
(Automated Quasar Detection) in a field of, centred at (1950) RA, Dec.. These observations,
with the CTIO 4-m telescope, led to the discovery by Clowes & Campusano of a large group …

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