Landing page for project EB109

Previous EVN observations have detected OH emission of a torus structure in OHMM Mrk 231 and evidence for a torus at one of the nuclei of Mrk 273. However, these observations have over-resolved most of the diffuse OH and continuum emission in these sources and they only show the more compact components. Recent observation of the prototype OHMM Arp220 show that the detection of both emission components are required to fully understand the masering action in the source. We propose re-observations using EVN and MERLIN in order determine the 3D (velocity-position) structure of both the compact and diffuse OH emission regions in these galaxies. Using a weighting scheme for the MERLIN and EVN data contributions, one may vary the resolution of the imaging and study the structure of the foreground and systemic masering regions. At intermediate resolution, Arp 220 the bulk of the diffuse OH emission originates in foreground regions, while the compact components are part of the two galaxy cores and identify the actual systemic velocity of these cores.

This data is part of the archive of VLBI data maintained by JIVE on behalf of the EVN, a network of radio telescopes located primarily in Europe and Asia, with additional antennas in South Africa. The EVN archive itself has the DOI https://doi.org/10.17616/R3Z197