2010/10/29 by W. -H. Hsu, Wen‐Hsin Hsu, M. E. Putman +7 · 1 citation
Physics and Astronomy · #Astrophysics #Astrophysics and Star Formation Studies #Galactic halo #Galaxies: Formation, Evolution, Phenomena #Galaxy #Halo #Metallicity #Physics #Stellar, planetary, and galactic studies #astro-ph.GA
paper · pdf · doi:10.1088/0004-6256/141/2/57
published as The Astronomical Journal, Volume 141, Issue 2, article id. 57 (2011) · Accepted for publication in AJ. 54 pages, including 6 tables and 16 figures
arxiv created 2010/10/29 · openalex publication_date 2011/01/13 · arxiv updated 2012/04/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Observations from the Galactic Arecibo L-band Feed Array H i (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 , 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 ☉ , 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 × 10 −4 cm −3 , which given a constant distance of 10 kpc is at a z -height of ∼3 kpc. Using the same argument for the Stream results in a median halo density of . 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 H i 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.