On the Kinematics of Cold, Metal-enriched Galactic Fountain Flows in Nearby Star-forming Galaxies

We use medium-resolution Keck/Echellette Spectrograph and Imager spectroscopy of bright quasars to study cool gas traced by Ca ii lambda lambda 3934, 3969 and Na i lambda lambda 5891, 5897 absorption in the interstellar/circumgalactic media of 21 foreground star-forming galaxies at redshifts 0.03 < z < 0.20 with stellar masses 7.4 <= log M (*)/M (circle dot) <= 10.6. The quasar-galaxy pairs were drawn from a unique sample of Sloan Digital Sky Survey quasar spectra with intervening nebular emission, and thus have exceptionally close impact parameters (R (perpendicular to) < 13 kpc). The strength of this line emission implies that the galaxies' star formation rates (SFRs) span a broad range, with several lying well above the star-forming sequence. We use Voigt profile modeling to derive column densities and component velocities for each absorber, finding that column densities N(Ca ii) > 10(12.5) cm(-2) (N(Na i) > 10(12.0) cm(-2)) occur with an incidence f (C)(Ca ii) = 0.63(+0.10) (-0.11) (f (C)(Na i) = 0.57(+0.10) (-0.11)). We find no evidence for a dependence of f (C) or the rest-frame equivalent widths W ( r )(Ca ii K) or W ( r )(Na i 5891) on R (perpendicular to) or M (*). Instead, W ( r )(Ca ii K) is correlated with local SFR at >3 sigma significance, suggesting that Ca ii traces star formation-driven outflows. While most of the absorbers have velocities within +/- 50 km s(-1) of the host redshift, their velocity widths (characterized by Delta v (90)) are universally 30-177 km s(-1) larger than that implied by tilted-ring modeling of the velocities of interstellar material. These kinematics must trace galactic fountain flows and demonstrate that they persist at R (perpendicular to) > 5 kpc. Finally, we assess the relationship between dust reddening and W ( r )(Ca ii K) (W ( r )(Na i 5891)), finding that 33% (24%) of the absorbers are inconsistent with the best-fit Milky Way E(B-V)-W ( r ) relations at >3 sigma significance.