Because the relative motion of the brighter components implied actual physical association rather than coincidental visual alignment, Félix Savary (1797 - 1841) was inspired to calculate the first orbit ever for a «double star» by applying Newton's «laws of gravity» in 1828, whose solution was subsequently provided by Herschel in 1829. (solstation.com)
The burst properties argue against a physical association with our Galaxy or the Small Magellanic Cloud. (science.sciencemag.org)
In a survey for Lyman - α emission at redshift z ≈ 2, we discovered a physical association of four quasars embedded in a giant nebula. (science.sciencemag.org)