2009/03/31 by Jayanne English, Baerbel Koribalski, B. Koribalski +8 · 35 citations
Physics and Astronomy · #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Dwarf galaxy #Galaxies: Formation, Evolution, Phenomena #Galaxy #Globular cluster #Local Group #Physics #Pulsar #Solar mass #Star formation #Stellar, planetary, and galactic studies #Vela #astro-ph.CO
paper · pdf · doi:10.1088/0004-6256/139/1/102
published in The Astronomical Journal 139(1), 102-119 (Institute of Physics) · 47 pages, 13 figures (incl. a & b), accepted by AJ, changes are minor additions, rearranging, and clarifications esp. in sections 6 & 7
arxiv created 2009/09/16 · openalex publication_date 2009/12/08 · arxiv updated 2015/05/13 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We present Australia Telescope Compact Array (ATCA) observations of a galaxy-sized intergalactic H i cloud ("the Vela Cloud") in the NGC 3256 galaxy group. The group contains the prominent merging galaxy NGC 3256, which is surrounded by a number of H i fragments, the tidally disturbed galaxy NGC 3263, and several other peculiar galaxies. The Vela Cloud, with an H i mass of 3–5 , resides southeast of NGC 3256 and west of NGC 3263, within an area of 9' × 16' (100 kpc × 175 kpc for an adopted distance of 38 Mpc). In our ATCA data the Vela Cloud appears as three diffuse components and contains four density enhancements. The Vela Cloud's properties, together with its group environment, suggest that it has a tidal origin. Each density enhancement contains of H i gas, which is sufficient material for the formation of globular cluster progenitors. However, if we represent the enhancements as Bonnor–Ebert spheres, then the pressure of the surrounding H i would need to increase by at least a factor of 9 in order to cause the collapse of an enhancement. Thus we do not expect them to form massive bound stellar systems like super star clusters or tidal dwarf galaxies. Since the H i density enhancements have some properties in common with high-velocity clouds, we explore whether they may evolve to be identified with these starless clouds instead.