Searching high-redshift large-scale structures:: Photometry of four fields around quasar pairs at z ∼ 1

We have studied the photometric properties of four fields around the high-redshift quasar pairs QP 1310+0007, QP 1355 - 0032, QP 0110 - 0219, and QP 0114 - 3140 at z similar to 1 with the aim of identifying large-scale structures ( galaxy clusters or groups) around them. This sample was observed with the Gemini Multi-Object Spectograph (GMOS) at the Gemini North and South telescopes in the g ', r ', i ', and z ' bands, and our photometry is complete to a limiting magnitude of i ' similar to 24mag ( corresponding to similar to M-i '* + 2 at the redshift of the pairs). Our analysis reveals that QP 0110-0219 shows very strong and QP 1310+0007 and QP 1355-0032 show some evidence for the presence of rich galaxy clusters in direct vicinity of the pairs. On the other hand, QP 0114-3140 could be an isolated pair in a poor environment. This work suggest that z similar to 1 quasar pairs are excellent tracers of high-density environments, and the same technique may be useful to find clusters at higher redshifts.