Galaxy pairs in the Sloan Digital Sky Survey – XII. The fuelling mechanism of low-excitation radio-loud AGN

摘要: We investigate whether the fuelling of low excitation radio galaxies (LERGs) is linked to major galaxy interactions. Our study utilizes a sample 10,800 spectroscopic pairs and 97 post-mergers selected from Sloan Digital Sky Survey with matches multi-wavelength datasets. The LERG fraction amongst interacting factor 3.5 higher than that control matched in local density, redshift stellar mass. However, excess does not depend on projected separation remains elevated out at least 500 h 1 70 kpc, suggesting mergers are their main channel. In order identify primary mechanism LERGs, we compile samples various host environmental properties. reduced, but completely removed, when halo mass or D4000 included matching parameters. both Mhalo matched, there no 1.4 GHz luminosities (which trace jet mechanical power) consistent between control. contrast, optical mid-IR AGN unchanged additional parameters implemented. results suggest whilst interactions may trigger optically AGN, gas which fuels LERGs has two secular origins: one associated large scale environment, such as accretion surrounding medium minor mergers, plus an internal mechanism, winds evolved stars.