OBSERVATIONS OF 10 FAINT QUASAR CANDIDATES IN THE FIELD OF THE TOLOLO-1037-2703/1038-2712 QUASAR PAIR

We present low-resolution slit spectra of a further 10 faint (B congruent-to 19-20) quasar candidates within the Bohuski and Weedman survey field containing the Tololo 1037-2703/1038-2712 wide quasar pair. We confirm that nine of these candidates are quasars or active galaxies with redshifts 0.171 l...

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Veröffentlicht in:The Astrophysical journal 1992-06, Vol.392 (2), p.432-441
Hauptverfasser: JAKOBSEN, P, PERRYMAN, MAC
Format: Artikel
Sprache:eng
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Zusammenfassung:We present low-resolution slit spectra of a further 10 faint (B congruent-to 19-20) quasar candidates within the Bohuski and Weedman survey field containing the Tololo 1037-2703/1038-2712 wide quasar pair. We confirm that nine of these candidates are quasars or active galaxies with redshifts 0.171 less-than-or-equal-to z(em) less-than-or-equal-to 2.55. This brings the total number of confirmed quasars within the field to 16. We also present exploratory higher resolution (DELTA-lambda congruent-to 10 angstrom) spectra of four objects whose redshifts place them behind or in the vicinity of the strong correlated absorption seen at 1.90 less than or similar to z(abs) less than or similar to 2.15 in the Tol 1037-2703/1038-2712 pair. One object, BW18, has a redshift of z(em) = 2.549 and is located only 3.'0 (D(perpendicular-to) congruent-to 740h-1 kpc) from Tol 1038-2712 of the pair and 2.'8 (D(perpendicular-to) congruent-to 670h-1 kpc) from the nearby z(em) = 1.91 quasar BW23. Our intermediate resolution spectrum of this object shows no strong C iv absorption above our detection threshold of W(lambda) congruent-to 2 angstrom matching the systems seen at z(em) congruent-to 2.08 and z(abs) congruent-to 2.15 in Tol 1038 - 2712, or the common system at z(abs) congruent-to 1.89 seen in both Tol 1038-2712 and BW23. However, an unidentified absorption feature seen near 4593 angstrom is possibly due to C IV at a redshift matching the z(abs) = 1.96 system seen in Tol 1038-2712. The other three confirmed high redshift quasars probe large projected distances of order D(perpendicular-to) congruent-to 20 h-1 Mpc from the pair. Two of the objects have emission redshifts of z(em) = 1.92 and z(em) = 2.17 and lie near the two extreme ends of the redshift range spanned by the absorption in Tol 1037-2703/1038-2712 and close to the redshifts of other quasars in the field. A weak z(abs) congruent-to z(em) system is probably present in the z(em) = 1.92 object, but otherwise our spectra reveal no clear cases of C IV absorption within the redshift range of interest stronger than W(lambda) greater than or similar to 2-4 angstrom. A three-dimensional map of the spatial location of the 13 quasars and the 21 C IV absorption systems at z > 1.5 detected to date in the Bohuski and Weedman field is presented, and the hypothesis that an intervening supercluster is responsible for the various redshift matches seen in the field is discussed. Some support for the concept of a sheetlike geometry f
ISSN:0004-637X
1538-4357
DOI:10.1086/171442