1998/03/19 by G. Petitpas, Glen R. Petitpas, C. D. Wilson +1 · 3 citations
Physics and Astronomy · #Astrophysics and Star Formation Studies #Galaxies: Formation, Evolution, Phenomena #Scientific Research and Discoveries #astro-ph
paper · pdf · doi:10.1086/305975
published as Astrophys.J. 503 (1998) 219 · 15 pages with 10 figures. To appear in the August 10 1998 issue of The Astrophysical Journal
arxiv created 1998/03/19 · openalex publication_date 1998/08/10 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
This paper presents [C I], 12 CO J = 4-3, and 12 CO J = 3-2 maps of the barred spiral galaxy M83 taken at the James Clerk Maxwell Telescope. Observations indicate a double-peaked structure, which is consistent with gas inflow along the bar collecting at the inner Lindblad resonance. This structure suggests that nuclear starbursts can occur even in galaxies where this inflow/collection occurs, in contrast to previous studies of barred spiral galaxies. However, the observations also suggest that the double-peaked emission may be the result of a rotating molecular ring oriented nearly perpendicular to the main disk of the galaxy. The 12 CO J = 4-3 data indicate the presence of warm gas in the nucleus that is not apparent in the lower J CO observations, which suggests that 12 CO J = 1-0 emission may not be a reliable tracer of molecular gas in starburst galaxies. The 12 [C I]/ 12 CO J = 4-3 line ratios in the inner 24'' × 24'' are uniform at the 2 σ level, which indicates that the 12 CO J = 4-3 emission is originating in the same hot photon-dominated regions as the [C I] emission. The 12 CO J = 4-3/ J = 3-2 line ratios vary significantly within the nucleus, with the higher line ratios occurring away from peaks of emission along an arc of active star-forming regions. These high line ratios (>1) likely indicate optically thin gas created by the high temperatures caused by star-forming regions in the nucleus of this starburst galaxy.