Distances To Galactic High-Velocity Clouds: Complex C

Access full-text files

2007_12_galactichighvelocity.pdf (157.35 KB)

Date

2007-12

Authors

Wakker, B. P.
York, D. G.
Howk, J. C.
Barentine, John C.
Wilhelm, R.
Peletier, R. F.
van Woerden, H.
Beers, Timothy C.
Ivezic, Z.
Richter, P.

Journal Title

Journal ISSN

Volume Title

Publisher

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) x 10(6) M-circle dot, and the complex represents a mass inflow of 0.1-0.25 M-circle dot 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.

Department

Astronomy

Description

Keywords

galaxy : evolution, galaxy : general, galaxy : halo, galaxy : structure, ism : clouds, stars : distances, digital sky survey, data release, horizontal-branch, milky-way, galaxy, stars, metallicities, telescope, abundance, halo, astronomy & astrophysics

LCSH Subject Headings

Citation

Wakker, B. P., D. G. York, J. C. Howk, J. C. Barentine, R. Wilhelm, R. F. Peletier, H. van Woerden et al. "Distances to galactic high-velocity clouds: complex C." The Astrophysical Journal Letters, Vol. 670, No. 2 (Dec., 2007): L113.

URI

http://hdl.handle.net/2152/35086

Collections

UT Faculty/Researcher Works