@prefix rdf: . @prefix xsd: . @prefix dcterms: . @prefix skos: . @prefix rdfs: . @prefix api: . @prefix foaf: . a rdfs:Resource , skos:Concept ; dcterms:contributor ; dcterms:modified "2020-10-30T19:21:05.374Z"^^xsd:dateTime ; skos:altLabel "Chwolson ring"@en , "Einstein-Chwolson ring"@en ; skos:broader ; skos:definition "The apparent shape of a background source undergoing the effect of gravitational lensing as seen from Earth, provided that the source, the intervening lens, and the observer are in perfect alignment through Einstein radius."@en ; skos:narrower ; skos:prefLabel "Einstein rings"@en . skos:narrower . skos:broader . a api:ItemEndpoint , api:Page ; api:definition ; api:extendedMetadataVersion ; foaf:primaryTopic .