Kinematics of the Galactic halo from horizontal branch stars in the Hamburg/ESO survey

Christopher Thom*, Chris Flynn, Michael S. Bessell, Jyrki Hänninen, Timothy C. Beers, Norbert Christlieb, Dionne James, Johan Holmberg, Brad K. Gibson

*Corresponding author for this work

    Research output: Contribution to journalReview articlepeer-review

    12 Citations (Scopus)


    Large samples of field horizontal branch (FHB) stars make excellent tracers of the Galactic halo; by studying their kinematics, one can infer important physical properties of our Galaxy. Here we present the results of a medium-resolution spectroscopic survey of 530 FHB stars selected from the Hamburg/ESO survey. The stars have a mean distance of ∼7 kpc and thus probe the inner parts of the Milky Way halo. We measure radial velocities from the spectra in order to test the model of Sommer-Larsen et al., who suggested that the velocity ellipsoid of the halo changes from radially dominated orbits to tangentially dominated orbits as one proceeds from the inner to the outer halo. We find that the present data are unable to discriminate between this model and a more simple isothermal ellipsoid; we suggest that additional observations towards the Galactic Centre might help to differentiate them.

    Original languageEnglish
    Pages (from-to)354-359
    Number of pages6
    JournalMonthly Notices of the Royal Astronomical Society
    Issue number1
    Publication statusPublished - 11 Jun 2005


    Dive into the research topics of 'Kinematics of the Galactic halo from horizontal branch stars in the Hamburg/ESO survey'. Together they form a unique fingerprint.

    Cite this