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Astron. Astrophys. 343, 352-366 (1999)

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Automated supershell recognition in spiral galaxies employing hydrodynamic simulations

S.Y. Mashchenko 1, D.A. Thilker 2 and R. Braun 1

1 Netherlands Foundation for Research in Astronomy, Postbus 7990 AA, Dwingeloo, The Netherlands (e-mail: syam@phy.ulaval.ca, rbraun@nfra.nl)
2 Department of Astronomy, New Mexico State University, Box 30001 / Dept 4500, Las Cruces, NM 88003-8001 (e-mail: dthilker@nmsu.edu)

Received 29 May 1998 / Accepted 20 November 1998


The search for expanding supershells in nearby galaxies has been the focus of substantial observational effort since the discovery of huge HI bubbles in the Magellanic clouds. Until recently, studies of this nature were limited: initially due to the lack of detailed models describing the predicted appearance of supershells, subsequently because it is challenging to quantify the similarity of model and data over numerous channel maps by visual inspection. Thilker et al. (1998a) first established a method for automated identification and classification of supershells in spiral galaxies. Their object recognition technique is capable of locating complex 3-dimensional patterns in a spectral-line datacube via cross-correlation analysis. We report on various refinements to the basic method and discuss the implications for one particular galaxy (NGC 2403). Most significantly, we now incorporate realistic hydrodynamic models of superbubble structure. We also introduce more robust treatment of shell significance, especially for the case of overlapping structures.

Key words: infrared: galaxies – galaxies: ISM – galaxies: individual: NGC 2403 – ISM: bubbles – methods: data analysis – hydrodynamics

Present address: Département de Physique and Observatoire du Mégantic, Université Laval, Québec, Qc., Canada, G1K 7P4

Send offprint requests to: S.Y. Mashchenko

© European Southern Observatory (ESO) 1999

Online publication: March 1, 1999