1999/01/29 by Claudia Winge, Cláudia Winge, D. J. Axon +5 · 8 citations
Physics and Astronomy · #Astrophysics and Star Formation Studies #Galaxies: Formation, Evolution, Phenomena #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/307337
published as Astrophys.J. 519 (1999) 134-152 · 30 pages (aaspp4.sty), 14 figures. Fig. 1, 2 and 4 available by anonymous FTP at 143.54.2.51 (cd /pub/winge) as GIF files; or upon request to [email protected]. Accepted for publication in the Astrophysical Journal (part 1)
arxiv created 1999/01/29 · openalex publication_date 1999/07/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/01
We present the results from a detailed kinematic analysis of both ground-based, and Hubble Space Telescope ( HST )/Faint Object Camera long-slit spectroscopy at subarcsecond spatial resolution of the narrow-line region (NLR) of NGC 4151. In agreement with previous work, the extended emission gas ( R > 4'') is found to be in normal rotation in the galactic plane, a behavior that we were able to trace even across the nuclear region, where the gas is strongly disturbed by the interaction with the radio jet and connects smoothly with the large-scale rotation defined by the neutral gas emission. The HST data, at 0 029 spatial resolution, allow us for the first time truly to isolate the kinematic behavior of the individual clouds in the inner narrow-line region. We find that, underlying the perturbations introduced by the radio ejecta, the general velocity field can still be well represented by planar rotation down to a radius of ~0 5 (30 pc), the distance at which the rotation curve has its turnover. The most striking result that emerges from our analysis is that the galaxy potential derived fitting the rotation curve changes from a "dark halo" at the extended narrow-line region distances to being dominated by the central mass concentration in the NLR, with an almost Keplerian falloff in the 1'' < R < 4'' interval. The observed velocity of the gas at 0 5 implies a mass of M ~ 10 9 M ☉ within the inner 60 pc. The presence of a turnover in the rotation curve indicates that this central mass concentration is extended. The first measured velocity point (outside the region saturated by the nucleus) would imply an enclosed mass of ~5 × 10 7 M ☉ within R ~ 0 15 (10 pc), which represents an upper limit to any nuclear point mass.