Search for H I emission from superdisk candidates associated with radio galaxies

摘要: Giant gaseous layers (termed ``superdisks'') have been hypothesized in the past to account for strip-like radio emission gap (or straight-edged central brightness depression) observed between twin lobes, over a dozen relatively nearby powerful Fanaroff-Riley Class II galaxies. They could also provide plausible alternative explanation range of observations. Although number explanations proposed origin superdisks, little is known about their material content. Some X-ray observations superdisk candidates indicate presence hot gas, but cool dusty medium seems be common. If they are entirely or partly composed neutral then it may directly detectable and we report here first attempt detect/image any hydrogen gas present superdisks that inferred four We not found positive H I signal sources, resulting tight upper limits on density postulated estimated from rms noise values final continuum subtracted image. The ranges limit column 10(-4) - 10(-3) atoms per cm(3) 10(19) 10(20) cm(2), respectively. No detected even after combining all available images (with inverse variance weighting). This clearly rules out an dominated as viable model explain these structures, however, possibility being warm/hot still remains open.