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Please use this identifier to cite or link to this item: http://hdl.handle.net/10481/28413

Title: Dependence of radio halo properties on star formation activity and galaxy mass
Authors: Dahlem, M.
Lisenfeld, Ute
Rossa, J.
Issue Date: 2006
Abstract: We investigate the relation between the existence and size of radio halos, which are believed to be created by star formation (SF) related energy input into the interstellar medium, and other galaxy properties, most importantly star formation activity and galaxy mass. Based on radio continuum and H$\alpha$ observations of a sample of seven late-type spiral galaxies we find a direct, linear correlation of the radial extent of gaseous halos on the size of the actively star-forming parts of the galaxy disks. Data of a larger sample of 22 galaxies indicate that the threshold energy input rate into the disk ISM per unit surface area for the creation of a gaseous halo depends on the mass surface density of the galaxy, in the sense that a higher threshold must be surpassed for galaxies with a higher surface density. Because of the good prediction of the existence of a radio halo from these two parameters, we conclude that they are important, albeit not the only contributors. The compactness of the SF-related energy input is also found to be a relevant factor. Galaxies with relatively compact SF distributions are more likely to have gaseous halos than others with more widespread SF activity. These results quantify the so-called "break-out" condition for matter to escape from galaxy disks, as used in all current models of the interstellar medium and first defined by Norman & Ikeuchi (1989).
Sponsorship: U.L. acknowledges support by the Spanish Ministry of Education, via the research projects AYA 2005-0716-C02-01, ESP 2004-06870-C02-02, and the Junta de Andalucía.
Publisher: European Southern Observatory (ESO); Springer Verlag
Keywords: ISM
Galaxies
Spiral
Evolution
Halos
Starburst
Radio continuum
URI: http://hdl.handle.net/10481/28413
ISSN: 0004-6361
1432-0746
Rights : Creative Commons Attribution-NonCommercial-NoDerivs 3.0 License
Citation: Dahlem, M.; Lisenfeld, U.; Rossa, J. Dependence of radio halo properties on star formation activity and galaxy mass. Astronomy and Astrophysics, 457(1): 121-131 (2006). [http://hdl.handle.net/10481/28413]
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