Paired quasars near NGC 2639: Evidence for quasars in superclusters

Journal Article · Tue Mar 15 04:00:00 EST 1983 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/160792· OSTI ID:5940388

Ford, H; Ciardullo, R; Harms, R

Arp found 10 quasars near a low-redshift galaxy 27' SSE of NGC 2639. Six of the quasars can be grouped into three redshift pairs which align across the anonymous galaxy. The large number of quasars and pairings could show an association with the low-redshift galaxy, or alternatively, might be due to superclusters seen along the line of sight. We tested the latter hypothesis by using deep, red-sensitive Lick 3 m prime focus plates to search for a supercluster associated with the z = 0.3 quasar pair. The plates show extended nebulosity associated with the quasar U10 (thetaapprox.7'', or 20 kpc at z = 0.3) and a richness class 1, Bautz-Morgan type III cluster 4' NW of U10. A spectrum of one the cluster's brightest galaxies gives z = 0.34, suggesting that the cluster and quasar are unassociated. We obtained spectra of eight of the quasars and find that (i) two of the quasars have very strong absorption shortward of Ly..cap alpha.., and (ii) two of Arp's redshifts (including one which Arp considered uncertain) are incorrect. Our redshifts break two of the redshift pairs, including the pair at z = 0.3. We use the redshift distribution of optically selected quasars to argue that the third pair has no statistical significance, and conclude that there is no basis for associating the quasars with the low-redshift anonymous galaxy. The disappearance of the redshift pairs vitiates the possibility of testing the paired-quasars-in-superclusters hypothesis in the NGC 2639 field.

• Research Organization: University of California, Los Angeles
• OSTI ID: 5940388
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 266:2; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640103* -- Astrophysics & Cosmology-- Quasi-Stellar
Radio
& X-Ray Sources-- (-1987)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COSMIC RADIO SOURCES
COSMOLOGY
GALAXIES
GALAXY CLUSTERS
PHOTOGRAPHY
QUASARS
RED SHIFT
SPECTRA
SPECTROSCOPY
VISIBLE SPECTRA