1998/02/20 by J. R. Herrnstein, L. J. Greenhill, J. M. Moran +4 · 2 citations
Physics and Astronomy · #Accretion (finance) #Accretion disc #Astrophysical Phenomena and Observations #Astrophysics and Cosmic Phenomena #Flow (mathematics) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Limit (mathematics) #Schwarzschild radius #Very Long Baseline Array #astro-ph
paper · pdf · doi:10.1086/311284
11 pages, 1 figure, to be published in ApJ Letters
arxiv created 1998/02/20 · openalex publication_date 1998/04/20 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We report a 3 σ upper limit of 220 μJy on any 22 GHz continuum emission coincident with the central engine in NGC 4258. If NGC 4258 is powered by an advection-dominated accretion flow, this radio upper limit implies that the inner advection-dominated flow cannot extend significantly beyond ~10 2 Schwarzschild radii.