Description
We present a survey of the mass surface density of spiral disks, motivated by outstanding uncertainties in rotation-curve decompositions. Our method exploits integral-field spectroscopy to measure stellar and gas kinematics in nearly face-on galaxies sampled at 515, 660, and 860nm, using the custom-built SparsePak and PPak instruments. A two-tiered sample, selected from the UGC, includes 146 nearly face-on galaxies, with B<14.7 and disk scale lengths between 10 and 20 arcsec, for which we have obtained H{alpha} velocity fields; and a representative 46 galaxy subset for which we have obtained stellar velocities and velocity dispersions. The survey is augmented by 4-70um Spitzer IRAC and MIPS photometry, ground-based UBVRIJHK photometry, and HI aperture-synthesis imaging. We outline the spectroscopic analysis protocol for deriving precise and accurate line-of-sight stellar velocity dispersions. Our key measurement is the dynamical disk-mass surface density. Star formation rates and kinematic and photometric regularity of galaxy disks are also central products of the study.
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