The spatially resolved star formation law in nearby galaxies [Elektronische Ressource] / presented by Frank Bigiel

Dissertationsubmitted to theCombined Faculties for the Natural Sciences and for Mathematicsof the Ruperto-Carola University of Heidelberg, Germanyfor the degree ofDoctor of Natural SciencesPresented byDipl.-Phys. Frank Bigielborn in Augsburg, GermanyOral examination: 27.06.2008The Spatially ResolvedStar Formation Lawin Nearby GalaxiesReferees: Prof. Dr. Ralf S. KlessenDr. Fabian WalterAbstractThis thesis presents a comprehensive analysis of the relationship between gas and star formation(SF) at sub-kpc resolution in a large sample of nearby galaxies. The analysis is based on recentvery high quality radio, infrared and UV data. Key to this thesis are new, sensitive and highresolution atomic gas maps from ‘The HI Nearby Galaxy Survey’ (THINGS). A combination ofthesemultiwavelengthdataareusedtostudythegas-SFrelationacrosstheH –dominatedcenters2of the spirals as well as their HI–dominated outskirts and HI–rich late type/dwarf galaxies.For the spiral galaxies, a Schmidt-type power law with index N =1.0±0.2 relates star formationrate and H . This implies that H forms stars at a constant efficiency, i.e. star formation rate per2 2unit gas, in spirals. Most galaxies show little or no correlation between the star rateand HI. The star formation efficiency is observed to decrease with increasing radius in the spirals,while the dwarf galaxies in our sample display star formation efficiencies similar to those foundin the outer optical disks of the spirals.