Study of multiple nucleus galaxies. II. MKN 739.

Abstract

An investigation of the Markarian galaxy MKn 739 is reported. The investigation used spectroscopic data from ground and space, radio observations, IRAS data and CCD imaging. Component A is a Seyfert type 1 nucleus with strong Fe II lines, very steep continuum and no trace of Lyman alpha and CIV 1549. Component B is a starburst nucleus, quite similar to the two nuclei of Mkn 788. The lack of a strong 'blue bump', the steep continuum and the extremely weak ultraviolet lines, make Mkn 739 unique among Seyfert 1 nuclei. It is suggested that the dust is distributed between the nuclei, thus preventing the ionizing radiation of nucleus A from reaching the gas near nucleus B. It also obscures part of nucleus B and causes a shift between the emission lines and continuum images. The large amount of dust and the mixture of many late type stars together with a strong H II region, may be a common property of many multiple-nucleus galaxies. The velocity curve of Mkn 739 is very unusual, showing indications of one nucleus moving at almost a right angle to the plane of the parent galaxy.