PI: Guilin Liu, University of Massachusetts, firstname.lastname@example.org
Address: Department of Astronomy, 710 N. Pleasant St., Amherst, MA 01003, USA
CoI: Daniela Calzetti, University of Massachusetts
Title: Exploring the Scaling Laws of Star Formation: the High Density Centers of Galaxies
Abstract: We propose to obtain H(alpha) and R-band images for a sample of 31 nearby star forming galaxies, which are part of an extensive investigation of the spatially-resolved Schmidt-Kennicutt Law of star formation in the high-density regime of the circumnuclear regions of galaxies. The proposed galaxies are part of a sample of 84, for which we have already obtained HST/NICMOS P(alpha) (1.876 (mu)m) images, which we are combining with archival interferometric CO maps. Line maps trace recent star formation, while CO traces the cold gas. The proposed H(alpha) observations will address two extant limitations in our current data: (1) presence of dust extinction which affects even P(alpha) by more than a factor of 2 in the centers of galaxies; (2) presence of low surface brightness line emission, not traced by HST. We will use the KPNO 2.1-m telescope images to remove dust extinction via the H(alpha)/P(alpha) ratio, and to trace the low-luminosity ionized gas surrounding the HII-region emission peaks. This will represent a unique sample of high-accuracy star formation rate measurements on physical scales of about 50 pc (the typical size of HII complexes). These observations will enable precise derivations of HII region luminosity functions and a thorough investigation of the scaling laws of star formation, and its dependence on the local environment. A previous proposal (ID 2009B-0397), to image 17 galaxies, has been approved for time, and the present proposal seeks to complete the H(alpha) imaging of our galaxy sample by requesting observations for the remaining 31 galaxies, thus providing a unique and \bf homogeneous survey of `dust- free' star formation.
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