The nuclei of most galaxies host supermassive black holes containing millions to billions of solar-masses of material. The immediate environments of these black holes typically include a tori of dust and gas and, as material falls toward the black hole, the gas radiates copiously at all wavelengths. Although the models for these active galactic nuclei (AGN) work reasonably well, it is difficult to obtain direct evidence of the inner structures of AGN because they are so far away and their dimensions are thought to be only tens to hundreds of light-years.
The scientists are able to resolve the continuum emission structure of the two individual nuclei into its dust and hot gas components. They report that each nucleus has two concentric components, the larger ones probably associated with starburst disks somehow activated by the black holes; the smaller ones, roughly 60 light-years in size, contribute as much as 50% of the submillimeter luminosity, nearly double the previous estimates. In fact one of the cores alone has a luminosity of about three trillion suns, larger than the entire emission of other AGN, not to mention the relatively small volume that is producing it. The cores in Arp220 also seems to have a third, extended linear feature that could represent the outflow seen before only in the spectroscopic (velocity) data.
The findings are published in The Astrophysical Journal.
Source: Harvard-Smithsonian Center for Astrophysics [January 24, 2018]