Distances to galactic high-velocity clouds: Complex C

B. P. Wakker; D. G. York; J. C. Howk; J. C. Barentine; R. Wilhelm; R. F. Peletier; H. Van Woerden; T. C. Beers; Ž Ivezić; P. Richter; U. J. Schwarz

doi:10.1086/524222

Distances to galactic high-velocity clouds: Complex C

B. P. Wakker, D. G. York, J. C. Howk, J. C. Barentine, R. Wilhelm, R. F. Peletier, H. Van Woerden, T. C. Beers, Ž Ivezić, P. Richter, U. J. Schwarz

Physics And Astronomy

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132 Scopus citations

Abstract

We report the first determination of a distance bracket for the high-velocity cloud (HVC) complex C. Combined with previous measurements showing that this cloud has a metallicity of 0.15 times solar, these results provide ample evidence that complex C traces the continuing accretion of intergalactic gas falling onto the Milky Way. Accounting for both neutral and ionized hydrogen as well as He, the distance bracket implies a mass of (3-14) × 10 ⁶ M_⊙, and the complex represents a mass inflow of 0.1-0.25 M⊙ yr^-1. We base our distance bracket on the detection of Ca ii absorption in the spectrum of the blue horizontal branch (BHB) star SDSS J120404.78+623345.6, in combination with a significant nondetection toward the BHB star BS 16034-0114. These results set a strong distance bracket of 3.7-11.2 kpc on the distance to complex C. A more weakly supported lower limit of 6.7 kpc may be derived from the spectrum of the BHB star BS 16079-0017.

Original language	English
Pages (from-to)	L113-L116
Journal	Astrophysical Journal
Volume	670
Issue number	2 PART 2
DOIs	https://doi.org/10.1086/524222
State	Published - 2007

Keywords

Galaxy: evolution
Galaxy: general
Galaxy: halo
Galaxy: structure
ISM: clouds
Stars: distances

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

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10.1086/524222

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title = "Distances to galactic high-velocity clouds: Complex C",

abstract = "We report the first determination of a distance bracket for the high-velocity cloud (HVC) complex C. Combined with previous measurements showing that this cloud has a metallicity of 0.15 times solar, these results provide ample evidence that complex C traces the continuing accretion of intergalactic gas falling onto the Milky Way. Accounting for both neutral and ionized hydrogen as well as He, the distance bracket implies a mass of (3-14) × 10 6 M⊙, and the complex represents a mass inflow of 0.1-0.25 M⊙ yr-1. We base our distance bracket on the detection of Ca ii absorption in the spectrum of the blue horizontal branch (BHB) star SDSS J120404.78+623345.6, in combination with a significant nondetection toward the BHB star BS 16034-0114. These results set a strong distance bracket of 3.7-11.2 kpc on the distance to complex C. A more weakly supported lower limit of 6.7 kpc may be derived from the spectrum of the BHB star BS 16079-0017.",

keywords = "Galaxy: evolution, Galaxy: general, Galaxy: halo, Galaxy: structure, ISM: clouds, Stars: distances",

author = "Wakker, {B. P.} and York, {D. G.} and Howk, {J. C.} and Barentine, {J. C.} and R. Wilhelm and Peletier, {R. F.} and {Van Woerden}, H. and Beers, {T. C.} and {\v Z} Ivezi{\'c} and P. Richter and Schwarz, {U. J.}",

year = "2007",

doi = "10.1086/524222",

language = "English",

volume = "670",

pages = "L113--L116",

number = "2 PART 2",

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TY - JOUR

T1 - Distances to galactic high-velocity clouds

T2 - Complex C

AU - Wakker, B. P.

AU - York, D. G.

AU - Howk, J. C.

AU - Barentine, J. C.

AU - Wilhelm, R.

AU - Peletier, R. F.

AU - Van Woerden, H.

AU - Beers, T. C.

AU - Ivezić, Ž

AU - Richter, P.

AU - Schwarz, U. J.

PY - 2007

Y1 - 2007

N2 - We report the first determination of a distance bracket for the high-velocity cloud (HVC) complex C. Combined with previous measurements showing that this cloud has a metallicity of 0.15 times solar, these results provide ample evidence that complex C traces the continuing accretion of intergalactic gas falling onto the Milky Way. Accounting for both neutral and ionized hydrogen as well as He, the distance bracket implies a mass of (3-14) × 10 6 M⊙, and the complex represents a mass inflow of 0.1-0.25 M⊙ yr-1. We base our distance bracket on the detection of Ca ii absorption in the spectrum of the blue horizontal branch (BHB) star SDSS J120404.78+623345.6, in combination with a significant nondetection toward the BHB star BS 16034-0114. These results set a strong distance bracket of 3.7-11.2 kpc on the distance to complex C. A more weakly supported lower limit of 6.7 kpc may be derived from the spectrum of the BHB star BS 16079-0017.

AB - We report the first determination of a distance bracket for the high-velocity cloud (HVC) complex C. Combined with previous measurements showing that this cloud has a metallicity of 0.15 times solar, these results provide ample evidence that complex C traces the continuing accretion of intergalactic gas falling onto the Milky Way. Accounting for both neutral and ionized hydrogen as well as He, the distance bracket implies a mass of (3-14) × 10 6 M⊙, and the complex represents a mass inflow of 0.1-0.25 M⊙ yr-1. We base our distance bracket on the detection of Ca ii absorption in the spectrum of the blue horizontal branch (BHB) star SDSS J120404.78+623345.6, in combination with a significant nondetection toward the BHB star BS 16034-0114. These results set a strong distance bracket of 3.7-11.2 kpc on the distance to complex C. A more weakly supported lower limit of 6.7 kpc may be derived from the spectrum of the BHB star BS 16079-0017.

KW - Galaxy: evolution

KW - Galaxy: general

KW - Galaxy: halo

KW - Galaxy: structure

KW - ISM: clouds

KW - Stars: distances

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U2 - 10.1086/524222

DO - 10.1086/524222

M3 - Article

AN - SCOPUS:42549100640

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SP - L113-L116

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 2 PART 2

ER -

Distances to galactic high-velocity clouds: Complex C

Abstract

Keywords

ASJC Scopus subject areas

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