Activity in Interacting and Binary Galaxies

Abstract

This is a short review of recent studies and reports on interacting galaxies and binary galaxies. Early studies were primarily made at optical wavelengths, but recent ones have concentrated on observing HI at λ21 cm. Application of the Virial Theorem to these observations indicates M/L values of the binary systems of ≲50, suggesting the existence of moderate halos around spiral galaxies.