IAU00907
Presentation type requested: EITHER
CONSTRAINTS ON A UNIVERSAL IMF FROM UV TO IR LUM DENSITIES
Ivan K Baldry
Johns Hopkins University
We obtain constraints on the slope of a universal stellar initial mass function (IMF) over a range of cosmic star-formation histories (SFH) using z = 0.1 luminosity densities in the range from 0.2 to 2.2 microns. The age-IMF degeneracy of integrated spectra of stellar populations can be broken for the Universe as a whole. Measurements of star-formation indicators with redshift constrain relative cosmic SFH with less dependence on the IMF than measurements of local luminosity densities. We fit to these measurements using population synthesis and find the best-fit IMF power-law slope to be -1.2 +- 0.2, assuming a constant slope from 0.5 to 120 solar masses. This is in good agreement with the Salpeter (1955) IMF slope (-1.35). A strong limit of -1.6 is obtained which effectively rules out the Scalo (1986) IMF due to its too low fraction of high-mass stars.
Glazebrook Karl
IAU XXV General Assembly | IAU216 HOME PAGE | IAU216 Speaker Program | IAU216 Poster Program