An Accurate Distance to High-Velocity Cloud Complex C

Abstract

We report an accurate distance of d = 10+/-2.5kpc to the high-velocity cloud Complex C. Using high signal-to-noise Keck/HIRES spectra of two horizontal-branch stars, we have detected CaII K absorption lines from the cloud. Significant non-detections toward a further 3 stars yield robust lower distance limits. The resulting HI mass of Complex C is 4.9^{+2.8}_{-2.2} x 10^6 Msun; a total mass of 8.2^{+4.6}_{-2.6} x 10^6 Msun is implied, after corrections for helium and ionization. At 10kpc, Complex C has physical dimensions 3x15 kpc, and if it is as thick as it is wide, then the average density is log<n> ~ -2.5. We estimate the contribution of Complex C to the mass influx may be as high as ~0.14 Msun/yr.

Resubmitted to ApJ. 8 figures

References in corpus (7)

• Cats and Dogs, Hair and A Hero: A Quintet of New Milky Way Companions
• The cold gaseous halo of NGC 891
• Distances to Galactic high-velocity clouds. I. Cohen Stream, complex GCP, cloud g1
• Distances to Galactic high-velocity clouds. Complex C
• The Local Group dwarf Leo T: HI on the brink of star formation
• Metallicity and Ionization in High Velocity Cloud Complex C
• Ongoing Galactic Accretion: Simulations and Observations of Condensed Gas in Hot Halos

Cited by in corpus (6)

• Seeding the formation of cold gaseous clouds in Milky Way size halos
• Smith's Cloud: A High-velocity Cloud Colliding with the Milky Way
• Properties and Origin of the High-Velocity Gas Toward the Large Magellanic Cloud
• Relics of structure formation: extra-planar gas and high-velocity clouds around the Andromeda Galaxy
• Anomalous HI in NGC 2997
• A peculiar HI cloud near the distant globular cluster Pal 4