PHYSICAL PROPERTIES OF COMPLEX C HALO CLOUDS

Observations from the Galactic Arecibo L-band Feed Array Hi (GALFA-H I) Survey of the tail of Complex C are presented and the halo clouds associated with this complex are cataloged. The properties of the Complex C clouds are compared to clouds cataloged at the tail of the Magellanic Stream to provide insight into the origin and destruction mechanism of Complex C. Magellanic Stream and Complex C clouds show similarities in their mass distributions (slope = -0.7 and -0.6 log(N(log(mass)))/log(mass), respectively) and have a common line width of 20-30 km s(-1) (indicative of a warm component), which may indicate a common origin and/or physical process breaking down the clouds. The clouds cataloged at the tail of Complex C extend over a mass range of 10(1.1)-10(4.8) M-circle dot, sizes of 10(1.2)-10(2.6) pc, and have a median volume density and pressure of 0.065 cm(-3) and (P/k) = 580 K cm-3. We do not see a prominent two-phase structure in Complex C, possibly due to its low metallicity and inefficient cooling compared to other halo clouds. Assuming that the Complex C clouds are in pressure equilibrium with a hot halo medium, we find a median halo density of 5.8 x 10(-4) cm(-3), which given a constant distance of 10 kpc is at a z-height of similar to 3 kpc. Using the same argument for the Stream results in a median halo density of 8.4x10(-5)(60 kpc/d) cm(-3). These densities are consistent with previous observational constraints and cosmological simulations. We also assess the derived cloud and halo properties with three-dimensional grid simulations of halo Hi clouds and find that the temperature is generally consistent within a factor of 1.5 and the volume densities, pressures, and halo densities are consistent within a factor of three.