1997/02/10 by T. Wiklind, Tommy Wiklind, Wiklind, Tommy +9
Engineering · Physics and Astronomy · #Astronomical Observations and Instrumentation #Astronomy and Astrophysical Research #Astrophysics (astro-ph) #Astrophysics and Star Formation Studies #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/9702080
Accepted for publication in A&A, 13 pages A&A LaTeX, 12 Postscript figures included
arxiv created 1997/02/10 · openalex publication_date 1997/02/10 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Interferometric observations of the CO(1-0) line in the elliptical galaxy\nNGC759 shows that it contains 2 109 Mo of molecular gas, confined to a\ncircumnuclear ring with an average radius of only 650pc. The maximum gas\nsurface density is 750 Mo/pc2, which is comparable to the critical gas surface\ndensity for large scale gravitational instabilities. The low CO(2-1)/CO(1-0)\nratio of 0.4 is consistent with a two-component molecular gas, consisting of a\ncold and dense phase, containing most of the mass, and a warm and diffuse\ncomponent dominating the CO emission. We use a mass model for the underlying\ngalaxy which is applicable to spherical galaxies with an r1/4 luminosity\nprofile. This leads to more modest estimates of the molecular gas fraction and\ngas surface density then would have been derived using simpler models,\nsuggesting that many of the spectacular molecular gas properties of\nultraluminous FIR galaxies, which could be described by similar mass models,\nmay have to be revised. We discuss the possibility that NGC759 is in a late\nstage of a merging between two gas-rich disk galaxies.\n