Determining the local dark matter density with LAMOST data

Qiran Xia*, Chao Liu, Shude Mao, Yingyi Song, Lan Zhang, R. J. Long, Yong Zhang, Yonghui Hou, Yuefei Wang, Yue Wu

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    Abstract

    Measurement of the local dark matter density plays an important role in both Galactic dynamics and dark matter direct detection experiments. However, the estimated values from previous works are far from agreeing with each other. In this work, we provide a well-defined observed sample with 1427G-and K-type main-sequence stars from the Large Sky Area Multi-Object Fibre Spectroscopic Telescope spectroscopic survey, taking into account selection effects, volume completeness, and the stellar populations. We apply a vertical Jeans equation method containing a single exponential stellar disc, a razor thin gas disc, and a constant dark matter density distribution to the sample, and obtain a total surface mass density of 78.7+3.9 -4.7 M⊙ pc-2 up to 1 kpc and a local dark matter density of 0.018 ±0.0054 M⊙ pc-3We find that the sampling density (i.e. number of stars per unit volume) of the spectroscopic data contributes to about two-third of the uncertainty in the estimated values. We discuss the effect of the tilt term in the Jeans equation and find it has little impact on our measurement. Other issues, such as a non-equilibrium component due to perturbations and contamination by the thick-disc population, are also discussed.

    Original languageEnglish
    Pages (from-to)3839-3850
    Number of pages12
    JournalMonthly Notices of the Royal Astronomical Society
    Volume458
    Issue number4
    DOIs
    Publication statusPublished - 10 Mar 2016

    Keywords

    • Dark matter
    • Galaxy: Disc
    • Galaxy: Kinematics and dynamics

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