2007/01/06 by S. G. Djorgovski, F. Courbin, G. Meylan +6 · 6 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Galaxies: Formation, Evolution, Phenomena #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/519162
Submitted to ApJL, LaTeX, 13 pages, 4 eps figures, all included
arxiv created 2007/01/06 · openalex publication_date 2007/05/22 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/04
We report the discovery of the first known probable case of a physical triple quasar. A previously known double system, QQ 1429-008 at z = 2.076, is shown to contain a third, fainter QSO component at the same redshift. Deep optical and IR imaging has failed to reveal a plausible lensing galaxy group or a cluster, and we are unable to construct any viable lensing model that could lead to the observed distribution of source positions and relative intensities of the three QSO image components. There are also hints of differences in the broadband spectral energy distributions of the different components, which are more naturally understood if they are physically distinct active galactic nuclei (AGNs). Therefore, we conclude that this system is most likely a physical triple quasar, the first such close QSO grouping known at any redshift. The projected component separations are ~30-50 kpc, typical of interacting galaxy systems. The existence of this highly unusual system supports the standard picture in which galaxy interactions lead to the onset of QSO activity.