Tridimensional Spectrophotometric Study of the Extended Emission-Line Regions of the Infrared-Luminous Merger Markarian 266

Abstract

An extensive tridimensional spectrophotometric study of the extended emission-line regions of Mrk 266, a merging system of a Seyfert galaxy and a LINER, was performed. We obtained its narrow-band images of Hα, [OIII] λ5007, and [SII] λλ 6716, 6731 using an imaging Fabry-Perot interferometer with a tunable filter and area spectroscopic data by means of a slit-scan. From these data were found high-excitation regions characterized by large [OIII]/Hβ (∼ 10) and large HeII λ 4686/Hβ (≥ 0.2). These regions can be considered as being photoionized by a power-law continuum from the Seyfert nucleus. If the continuum is radiated isotropically, an ionizing luminosity of 1055–56 photons s−1 is required. This implies that the Seyfert nucleus is one of the most luminous Seyfert nuclei, and can dominate the heating of dust, emitting the enormous amount of infrared emission of Mrk 266 (∼ 3 × 1011L⊙). The line ratios and emission-line luminosities of the LINER nucleus can be interpreted as an indication of a central starburst with a bolometric luminosity of about 2–6 × 1010L⊙ and a large-scale outflow (“superwind”). Finally, we remark on the evolutionary nature of activities of Mrk 266.