Distances To Galactic High-Velocity Clouds. I. Cohen Stream, Complex Gcp, Cloud G1

dc.contributor.utaustinauthorBarentine, John C.en_US
dc.creatorWakker, B. P.en_US
dc.creatorYork, D. G.en_US
dc.creatorWilhelm, R.en_US
dc.creatorBarentine, John C.en_US
dc.creatorRichter, P.en_US
dc.creatorBeers, Timothy C.en_US
dc.creatorIvezic, Z.en_US
dc.creatorHowk, J. C.en_US
dc.date.accessioned2016-04-28T19:40:49Z
dc.date.available2016-04-28T19:40:49Z
dc.date.issued2008-01en
dc.description.abstractThe high- and intermediate-velocity interstellar clouds (HVCs/IVCs) are tracers of energetic processes in and around the Milky Way. Clouds with near-solar metallicity about 1 kpc above the disk trace the circulation of material between disk and halo (the Galactic fountain). The Magellanic Stream consists of gas tidally extracted from the SMC, tracing the dark matter potential of the Milky Way. Several other HVCs have low metallicity and appear to trace the continuing accretion of infalling intergalactic gas. These assertions are supported by the metallicities (0.1 to 1 solar) measured for about 10 clouds in the past decade. Direct measurements of distances to HVCs have remained elusive, however. In this paper we present four new distance brackets, using VLT observations of interstellar Ca II H and K absorption toward distant Galactic halo stars. We derive distance brackets of 5.0 to 11.7 kpc for the Cohen Stream (likely to be an infalling low-metallicity cloud), 9.8 to 15.1 kpc for Complex GCP (also known as the Smith Cloud or HVC 40-15+100 and with still unknown origin), 1.0 to 2.7 kpc for an IVC that appears associated with the return flow of the fountain in the Perseus arm, and 1.8 to 3.8 kpc for cloud g1, which appears to be in the outflow phase of the fountain. Our measurements further demonstrate that the Milky Way is accreting substantial amounts of gaseous material, which influences the Galaxy's current and future dynamical and chemical evolution.en_US
dc.description.departmentAstronomyen_US
dc.description.sponsorshipNSF AST 06-07154, PHY-02-16783en_US
dc.description.sponsorshipJINAen_US
dc.identifierdoi:10.15781/T2BJ93
dc.identifier.Filename2008_01_distancesgalactic.pdfen_US
dc.identifier.citationWakker, B. P., D. G. York, R. Wilhelm, J. C. Barentine, P. Richter, T. C. Beers, and J. C. Howk. "Distances to galactic high-velocity clouds. I. Cohen stream, complex GCP, cloud g1." The Astrophysical Journal, Vol. 672, No. 1 (Jan., 2008): 298.en_US
dc.identifier.doi10.1086/523845en_US
dc.identifier.issn0004-637Xen_US
dc.identifier.urihttp://hdl.handle.net/2152/35087
dc.language.isoEnglishen_US
dc.relation.ispartofen_US
dc.relation.ispartofserialAstrophysical Journalen_US
dc.rightsAdministrative deposit of works to Texas ScholarWorks: This works author(s) is or was a University faculty member, student or staff member; this article is already available through open access or the publisher allows a PDF version of the article to be freely posted online. The library makes the deposit as a matter of fair use (for scholarly, educational, and research purposes), and to preserve the work and further secure public access to the works of the University.en_US
dc.rights.restrictionOpenen_US
dc.subjectgalaxy : haloen_US
dc.subjectism : cloudsen_US
dc.subjectstars : distancesen_US
dc.subjectstars :en_US
dc.subjecthorizontal-branchen_US
dc.subjectdigital sky surveyen_US
dc.subjectrr lyrae starsen_US
dc.subjectinterstellar absorption-linesen_US
dc.subjecthigh-resolution observationsen_US
dc.subjecta-type starsen_US
dc.subjectmilky-wayen_US
dc.subjecth-ien_US
dc.subjecthorizontal-branchen_US
dc.subjectglobular-clusteren_US
dc.subjectlow-metallicityen_US
dc.subjectastronomy & astrophysicsen_US
dc.titleDistances To Galactic High-Velocity Clouds. I. Cohen Stream, Complex Gcp, Cloud G1en_US
dc.typeArticleen_US
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