An accurate distance to high-velocity cloud Complex C

C. Thom, J. E.G. Peek, M. E. Putman, Carl Heiles, K. M.G. Peek, R. Wilhelm

Research output: Contribution to journalArticlepeer-review

111 Scopus citations

Abstract

We report an accurate distance of d = 10 ± 2.5 kpc to the high-velocity cloud Complex C. Using high signal-to-noise ratio Keck HIRES spectra of two horizontal-branch stars, we have detected Ca n K absorption lines from the cloud. Significant nondetections toward a further three stars yield robust lower distance limits. The resulting H i mass of Complex C is M H I = 4.9-2.2+2.9 × 106 M ; a total mass of Mtot = 8.2-2.6 +4.6 × 106 M is implied, after corrections for helium and ionization. At 10 kpc, Complex C has physical dimensions 3 ×15 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 ∼0.14M yr-1.

Original languageEnglish
Pages (from-to)364-372
Number of pages9
JournalAstrophysical Journal
Volume684
Issue number1
DOIs
StatePublished - Sep 1 2008

Keywords

  • Galaxy: Evolution
  • Galaxy: halo
  • ISM: Clouds
  • ISM: Individual (Complex C)

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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