1. Distances to galactic high-velocity clouds
- Author
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Reynier Peletier, H. van Woerden, Donald G. York, Zeljko Ivezic, Ronald Wilhelm, Bart P. Wakker, J. C. Barentine, U. J. Schwarz, Philipp Richter, J. C. Howk, Timothy C. Beers, and Kapteyn Astronomical Institute
- Subjects
galaxy : halo ,TELESCOPE ,Metallicity ,Milky Way ,DATA RELEASE ,FOS: Physical sciences ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Star (graph theory) ,ISM : clouds ,METALLICITIES ,galaxy : evolution ,Ionization ,Astrophysics::Solar and Stellar Astrophysics ,stars : distances ,Astrophysics::Galaxy Astrophysics ,HORIZONTAL-BRANCH ,Physics ,Astrophysics (astro-ph) ,Astronomy and Astrophysics ,Horizontal branch ,galaxy : structure ,Accretion (astrophysics) ,GALAXY ,Bracket (mathematics) ,Space and Planetary Science ,HALO ,galaxy : general ,Intergalactic travel ,DIGITAL SKY SURVEY ,MILKY-WAY ,ABUNDANCE ,STARS - 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 3-14x10^6 M_sun, and the complex represents a mass inflow of 0.1-0.25 M_sun/yr. We base our distance bracket on the detection of CaII absorption in the spectrum of the blue horizontal branch star SDSS J120404.78+623345.6, in combination with a significant non-detection 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., Accepted for publication in ApJ Letters
- Published
- 2007