2 research outputs found
Discovery of a Probable Physical Triple Quasar
We report the discovery of the first known probable case of a physical triple
quasar (not a gravitational lens). 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 within the measurement errors. Deep optical and IR imaging at
the Keck and VLT telescopes has failed to reveal a plausible lensing galaxy
group or a cluster, and moreover, we are unable to construct any viable lensing
model which could lead to the observed distribution of source positions and
relative intensities of the three QSO image components. Furthermore, there are
hints of differences in broad-band spectral energy distributions of different
components, which are more naturally understood if they are physically distinct
AGN. 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 in the restframe are ~ 30 - 50 kpc for the standard
concordance cosmology, 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.Comment: Submitted to ApJL, LaTeX, 13 pages, 4 eps figures, all include
Three-body equations of motion in successive post-Newtonian approximations
There are periodic solutions to the equal-mass three-body (and N-body)
problem in Newtonian gravity. The figure-eight solution is one of them. In this
paper, we discuss its solution in the first and second post-Newtonian
approximations to General Relativity. To do so we derive the canonical
equations of motion in the ADM gauge from the three-body Hamiltonian. We then
integrate those equations numerically, showing that quantities such as the
energy, linear and angular momenta are conserved down to numerical error. We
also study the scaling of the initial parameters with the physical size of the
triple system. In this way we can assess when general relativistic results are
important and we determine that this occur for distances of the order of 100M,
with M the total mass of the system. For distances much closer than those,
presumably the system would completely collapse due to gravitational radiation.
This sets up a natural cut-off to Newtonian N-body simulations. The method can
also be used to dynamically provide initial parameters for subsequent full
nonlinear numerical simulations.Comment: 8 pages, 9 figure