2007/09/26 by Lynn D. Matthews, Lynn T. Matthews, Juan M. Uson · 4 citations
Physics and Astronomy · #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Dwarf galaxy #Galaxies: Formation, Evolution, Phenomena #Galaxy #Physics #Spiral galaxy #Star formation #Stellar, planetary, and galactic studies #Surface brightness #astro-ph
paper · pdf · doi:10.1088/0004-6256/135/1/291
published as Astron.J.135:291-318,2008 · submitted to AJ and revised according to the referee's comments; version with full resolution figures available at http://www.cfa.harvard.edu/~lmatthew
arxiv created 2007/09/26 · openalex publication_date 2007/12/12 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We have used the Very Large Array to image the H i 21 cm line emission in the edge-on Sd galaxy IC 2233 and the blue compact dwarf NGC 2537. We also present new optical B , R , and Hα imaging of IC 2233 obtained with the WIYN telescope. Despite evidence of localized massive star formation in the form of prominent H ii regions and shells, supergiant stars, and a blue integrated color, IC 2233 is a low surface brightness system with a very low global star formation rate (≲0.05 M ⊙ yr −1 ), and we detect no significant 21 cm radio continuum emission from the galaxy. The H i and ionized gas disks of IC 2233 are clumpy and vertically distended, with scale heights comparable to that of the young stellar disk. Both the stellar and H i disks of IC 2233 appear flared, and we also find a vertically extended, rotationally anomalous component of H i extending to ∼ 2.4 d 10 kpc from the midplane. The H i disk exhibits a mild lopsidedness as well as a global corrugation pattern with a period of ∼7 d 10 kpc and an amplitude of ∼150 d 10 pc. To our knowledge, this is the first time corrugations of the gas disk have been reported in an external galaxy; these undulations may be linked to bending instabilities or to underlying spiral structure and suggest that the disk is largely self-gravitating. Lying at a projected distance of from IC 2233, NGC 2537 has an H i disk with a bright, tilted inner ring and a flocculent, dynamically cold outer region that extends to ∼3.5 times the extent of the stellar light ( D 25 ). Although NGC 2537 is rotationally-dominated, we measure H i velocity dispersions as high as km s −1 near its center, indicative of significant turbulent motions. The inner rotation curve rises steeply, implying a strong central mass concentration. Our data indicate that IC 2233 and NGC 2537 do not constitute a bound pair and most likely lie at different distances. We also find no compelling evidence of a recent minor merger in either IC 2233 or NGC 2537, suggesting that both are examples of small disk galaxies evolving in relative isolation.