NOAO >   Observing Info >   Approved Programs >   2011B-0539

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Proposal Information for 2011B-0539


PI: Joshua Simon, Carnegie Observatories, jsimon@obs.carnegiescience.edu
Address: 813 Santa Barbara St., Pasadena, CA 91101, USA

CoI: Joshua Adams, University of Texas-Austin

Title: Testing the Bottom-Heavy IMF as a Function of Environment

Abstract: There are many theoretical reasons to expect that the stellar initial mass function (IMF) may not be universal across all types of galaxies and eras of star formation, but the empirical evidence for IMF variations is generally not yet compelling. Recent work by van Dokkum & Conroy has demonstrated that the equivalent widths of two gravity- sensitive near-infrared absorption features in the spectra of giant elliptical galaxies appear to require an IMF that is significantly more bottom-heavy than that found in the Milky Way. Observations of the same spectral features in globular clusters, however, show weaker absorption and support a standard IMF in those systems. We propose to use the SparsePak integral field unit at WIYN to explore these absorption features in a wider variety of objects, ranging from low surface brightness dwarf spheroidal galaxies to massive bulges in early-type spirals. These observations will reveal the conditions under which the bottom-heavy IMF is produced and provide new constraints on the universality of the IMF, or the lack thereof.


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