2005/02/03 by C. A. Garland, J. P. Williams, D. J. Pisano +3 · 3 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Galaxies: Formation, Evolution, Phenomena #astro-ph
paper · pdf · doi:10.1086/429362
published as Astrophys.J. 624 (2005) 714-725 · accepted for publication in the ApJ (vol 625)
arxiv created 2005/02/03 · openalex publication_date 2005/05/06 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
We present the results of a single-dish beam-matched survey of the three lowest rotational transitions of CO in a sample of 20 local ( D ≲ 70 Mpc) luminous compact blue galaxies (LCBGs). These ~ L *, blue, high surface brightness, starbursting galaxies were selected on the same criteria used to define LCBGs at higher redshifts. Our detection rate was 70%, with those galaxies having L B < 7 × 10 9 L ☉ not detected. We find that the H 2 masses of local LCBGs range from 6.6 × 10 6 to 2.7 × 10 9 M ☉ , assuming a Galactic CO-to-H 2 conversion factor. Combining these results with our earlier H I survey of the same sample, we find that the ratio of molecular to atomic gas mass is low, typically 5%-10%. Using a large velocity gradient model, we find that the average gas conditions of the entire interstellar medium in local LCBGs are similar to those found in the centers of star-forming regions in our Galaxy and in the nuclear regions of other galaxies. Star formation rates, determined from IRAS fluxes, are a few M ☉ yr -1 , much higher per unit dynamical mass than normal spiral galaxies. If this rate remains constant, the molecular hydrogen depletion timescales are short, ~10-200 Myr.