Journal article
Evidence for a nonuniform initial mass function in the local universe
GR Meurer, OI Wong, JH Kim, DJ Hanish, TM Heckman, J Werk, J Bland-Hawthorn, MA Dopita, MA Zwaan, B Koribalski, M Seibert, DA Thilker, HC Ferguson, RL Webster, ME Putman, PM Knezek, MT Doyle, MJ Drinkwater, CG Hoopes, VA Kilborn Show all
Astrophysical Journal | Published : 2009
Abstract
Many of the results in modern astrophysics rest on the notion that the initial mass function (IMF) is universal. Our observations of a sample of H i selected galaxies in the light of Hα and the far-ultraviolet (FUV) challenge this result. The extinction-corrected flux ratio FHα/ fFUV from these two tracers of star formation shows strong correlations with the surface brightness in Hα and the R band: low surface brightness (LSB) galaxies have lower FHα/fFUV ratios compared to high surface brightness galaxies as well as compared to expectations from equilibrium models of constant star formation rate (SFR) using commonly favored IMF parameters. Weaker but significant correlations of F Hα/fFUV wi..
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Awarded by Science and Technology Facilities Council
Funding Acknowledgements
Primary support for the work presented here was obtained through NASA GALEX Guest Investigator grant GALEX GI04-0105-0009 and NASA LTSA grant NAG5-13083 to G. R. Meurer. Additional support in the early phase of the SINGG project came through grants NASA grants NAG5-8279 (Astrophysical Data Products program), HST-GO-08201, and HST-GO-08113 to G. R. Meurer. This work benefited from useful discussions with Rob Kennicutt, Evan Skillman, Chris Flynn, and Guinnevere Kauffmann as well as constructive comments from the anonymous referee. Some of the first analysis work for this project occurred while G. R. Meurer was visiting Germany in 2007 September; he thanks his hosts in Munich (Sandra Savaglio and Uta Grothkpf) and in Freising (Ruth Lang and Armin Muller) for their hospitality.