IAU00822 {W}
Presentation type requested: POSTER
LARGE QUASAR GROUPS AS TRACERS OF LSS IN THE EARLY UNIVERSE
Chris P Haines
Osservatorio Astronomico di Capodimonte
At low redshifts quasars have been found to trace the same large-scale density enhancements as galaxies, delineating known large-scale structures. Quasar clustering on scales of 100-200 Mpc has also been observed at higher redshifts in the form of Large Quasar Groups (LQGs), which could represent the high-redshift counterparts of local superstructures such as the "Great Wall". We have been probing the galaxy content of a region towards two known LQGs, one of 14 quasars z=0.8, and a second of 23 quasars at z=1.3, via direct imaging and through a survey of MgII absorption from galaxy haloes via background quasars. Two structures, significant at the 1-2% level, are identified in the MgII absorber redshift distribution, coincident with the two LQGs redshifts. In a wide-field optical imaging survey, we find evidence for sheet-like structures extending over 20-30 Mpc at both z=0.8 and z=1.3, with an overall excess of 500 faint, red galaxies. We also find three clusters at z=0.8 and one at z=1.2, confirmed through optical-NIR colour-magnitude relations.
Clowes Roger G, Campusano Luis E, Williger Gerry M, Graham Matthew J
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