2014/12/15 by Qiran Xia, Chao Liu, Yan Xu +5 · 13 citations
Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Astrophysics and Star Formation Studies #Disc #Galaxy #Galaxy formation and evolution #LAMOST #Noon #Physics #Pleiades #Stars #Stellar, planetary, and galactic studies #Substructure #Velocity dispersion #astro-ph.GA
paper · pdf · doi:10.1093/mnras/stu2620
published in Monthly Notices of the Royal Astronomical Society 447(3), 2367-2377 (Oxford University Press) · 12 pages, 10 figures
arxiv created 2014/12/15 · arxiv updated 2014/12/17 · openalex publication_date 2015/01/08 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We use about 15 000 F/G nearby dwarf stars selected from the LAMOST pilot survey to map the U–V velocity distribution in the solar neighbourhood. An extreme deconvolution algorithm is applied to reconstruct an empirical multi-Gaussian model. In addition to the well-known substructures, e.g. Sirius, Coma Berenices, Hyades–Pleiades overdensities, several new substructures are unveiled. A ripple-like structure from (U, V) = (−120, −5) to (103, −32) km s−1 is clearly seen in the U–V distribution. This structure seems associated with resonance induced by the Galactic bar, since it is extended in U while having a small dispersion in V at the same time. A ridge structure between (U, V) = (−60, 40) and (−15, 15) km s−1 is also found. Although similar substructures have been seen in the Hipparcos data, their origin is still unclear. Another compact overdensity is seen at (U, V) = (−102, −24). With this large data sample, we find that the substructure located at V ∼ −70 km s−1 and the Arcturus group are essentially parallel in V, which may indicate that they originate from an unrelaxed disc component perturbed by the rotating bar.