2011/04/04 by John M. Cannon, Hans P. Most, Evan D. Skillman +9 · 1 citation
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Context (archaeology) #Dwarf galaxy #Galaxies: Formation, Evolution, Phenomena #Galaxy #Interstellar medium #Irregular galaxy #Local Group #Star formation #astro-ph.CO
paper · pdf · doi:10.1088/0004-637x/735/1/35
The Astrophysical Journal, in press. Full-resolution version available on request from the first author
arxiv created 2011/04/04 · openalex publication_date 2011/06/14 · arxiv updated 2015/05/27 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We present new multi-configuration Very Large Array H i spectral line observations of the M81 group dwarf irregular post-starburst galaxy DDO 165. The H i morphology is complex, with multiple column density peaks surrounding a large region of very low H i surface density that is offset from the center of the stellar distribution. The bulk of the neutral gas is associated with the southern section of the galaxy; a secondary peak in the north contains ∼15% of the total H i mass. These components appear to be kinematically distinct, suggesting that either tidal processes or large-scale blowout have recently shaped the interstellar medium (ISM) of DDO 165. Using spatially resolved position–velocity maps, we find multiple localized high-velocity gas features. Cross-correlating with radius–velocity analyses, we identify eight shell/hole structures in the ISM with a range of sizes (∼400–900 pc) and expansion velocities (∼7–11 km s −1 ). These structures are compared with narrow- and broadband imaging from the Kitt Peak National Observatory and the Hubble Space Telescope ( HST ). Using the latter data, recent works have shown that DDO 165's previous "burst" phase was extended temporally (≳1 Gyr). We thus interpret the high-velocity gas features, H i holes, and kinematically distinct components of the galaxy in the context of the immediate effects of "feedback" from recent star formation (SF). In addition to creating H i holes and shells, extended SF events are capable of creating localized high-velocity motion of the surrounding interstellar material. A companion paper connects the energetics from the H i and HST data.