Browsing by Author "García, A"

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    Quasars clustering at z ∼ 3 on scales ≲ 10 h-1 Mpc
    (2003) Infante, L; Varela, J; Moles, M; Hertling, G; García, A; Menanteau, F
    We test the hypothesis of whether high-redshift quasi-stellar objects (QSOs) would preferentially appear in small groups or pairs and whether they are associated with massive young clusters. We carried out a photometric search for Lyalpha emitters on scales less than or similar to 10 h(-1) Mpc in the fields of a sample of 47 z approximate to 3 known QSOs. Wide and narrowband filter color-magnitude diagrams were generated for each of the 6'.6 x 6'.6 fields. A total of 13 nonresolved objects with a significant color excess were detected as QSO candidates at a redshift similar to that of the target. All the candidates are significantly fainter than the reference QSOs, with only two of them within 2 mag of the central object. Follow-up spectroscopic observations have shown that five, i.e., about 40% of the candidates, are QSOs at the same redshift of the target; four are QSOs at different z ( two of them probably being a lensed pair at z = 1.47); two candidates are unresolved H II galaxies at z similar to 0.3; and one unclassified and one candidate turned out to be a CCD flaw. These data indicate that at least 10% of the QSOs at z similar to 3 do have companions. We have also detected a number of resolved, rather bright Lyalpha emitter candidates. Most likely, a large fraction of them might be bright galaxies with [O II] emission, at z approximate to 0.3. The fainter population of our candidates corresponds to the current expectations. Thus, there are no strong indications for the existence of an overdensity of Lyalpha galaxies brighter than m approximate to 25 around QSOs at z approximate to 3.