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

doi:10.1086/589960

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

Physics And Astronomy

Research output: Contribution to journal › Article › peer-review

105 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 M_tot = 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 language	English
Pages (from-to)	364-372
Number of pages	9
Journal	Astrophysical Journal
Volume	684
Issue number	1
DOIs	https://doi.org/10.1086/589960
State	Published - 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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10.1086/589960

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@article{5366298a8f4a41ad82a4ec8a80c79518,

title = "An accurate distance to high-velocity cloud Complex C",

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.",

keywords = "Galaxy: Evolution, Galaxy: halo, ISM: Clouds, ISM: Individual (Complex C)",

author = "C. Thom and Peek, {J. E.G.} and Putman, {M. E.} and Carl Heiles and Peek, {K. M.G.} and R. Wilhelm",

year = "2008",

month = sep,

day = "1",

doi = "10.1086/589960",

language = "English",

volume = "684",

pages = "364--372",

number = "1",

}

TY - JOUR

T1 - An accurate distance to high-velocity cloud Complex C

AU - Thom, C.

AU - Peek, J. E.G.

AU - Putman, M. E.

AU - Heiles, Carl

AU - Peek, K. M.G.

AU - Wilhelm, R.

PY - 2008/9/1

Y1 - 2008/9/1

N2 - 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.

AB - 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.

KW - Galaxy: Evolution

KW - Galaxy: halo

KW - ISM: Clouds

KW - ISM: Individual (Complex C)

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U2 - 10.1086/589960

DO - 10.1086/589960

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VL - 684

SP - 364

EP - 372

IS - 1

ER -

An accurate distance to high-velocity cloud Complex C

Abstract

Keywords

ASJC Scopus subject areas

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