Related papers: Three Moving Groups Detected in the LAMOST DR1 Arc…

The existence of a kinematically defined moving group of stars centred at U = -40, V = -17 km/s referred to as the Hyades Supercluster, has been suggested as the debris of an originally large star forming event, with its core being the…

We have compiled a catalog of late-type stars (F5-M) member of representative young disk stellar kinematic groups: the Local Association (Pleiades moving group, 20 - 150 Myr), Ursa Mayor group (Sirius supercluster, 300 Myr), and Hyades…

Hypervelocity stars (HVSs) travel so fast that they may leave the Galaxy. The tidal disruption of a binary system by the supermassive black hole in the Galactic center is widely assumed to be their ejection mechanism. To test the hypothesis…

Precise abundance ratios are determined for 94 dwarf stars with 5200 < Teff < 6300 K, -1.6 < [Fe/H] < -0.4, and distances D < 335 pc. Most of them have halo kinematics, but 16 thick-disk stars are included. Equivalent widths of atomic lines…

The Monoceros Ring (also known as the Galactic Anticenter Stellar Structure) and A13 are stellar overdensities at estimated heliocentric distances of $d \sim 11$ kpc and 15 kpc observed at low Galactic latitudes towards the anticenter of…

The Gaia mission has provided the largest ever astrometric chart of the Milky Way. Using it to map the Galactic halo is helpful for disentangling its merger history. The identification of halo stars in Gaia DR2 with reliable distance…

We present GALEX near ultraviolet (NUV:1750 - 2750A) and far ultraviolet (FUV: 1350 - 1750A) imaging observations of two 1.2 degree diameter fields in the Hyades and Pleiades open clusters in order to detect possible UV variability of the…

AIMS. We derive the morphology of the stellar component in the outer halo volume, and search for possible overdensities due to substructures therein. METHODS. We made use of some of the data releases of the spectroscopic survey LAMOST…

We describe a new survey for unbound hypervelocity stars (HVSs), stars traveling with such extreme velocities that dynamical ejection from a massive black hole (MBH) is their most likely origin. We investigate the possible contribution of…

In this paper, we investigate whether overdensity formation via streaming instability is consistent with recent multi-wavelength ALMA observations in the Lupus star forming region. We simulate the local action of streaming instability in 2D…

Based on the Gaia DR2 catalogue of hot subdwarf star candidates, we identified 1587 hot subdwarf stars with spectra in LAMOST DR7. We present atmospheric parameters for these stars by fitting the LAMOST spectra with {\sc Tlusty/Synspec}…

We present the first measurements of [Fe/H] and [$\alpha$/Fe] abundances, obtained using spectral synthesis modeling, for red giant branch stars in M31's giant stellar stream. The spectroscopic observations, obtained at a projected distance…

We present three-dimensional space velocities of stars selected to be consistent with membership in the Virgo stellar substructure. Candidates were selected from SA 103, a single 40x40 arcmin field from our proper motion (PM) survey in…

Hypervelocity stars (HVSs) are produced by the Hills mechanism when a stellar binary is disrupted by a supermassive black hole (SMBH). The HVS Survey detected 21 unbound B-type main-sequence stars in the Milky Way's outer halo that are…

The Pan Andromeda Archeological Survey (PAndAS) CFHT Megaprime survey of the M31-M33 system has found a star stream which extends about 120 kpc NW from the center of M31. The great length of the stream, and the likelihood that it does not…

With the photometric data from the SDSS survey, the spectroscopic data from the SDSS/SEGUE and the LAMOST surveys, and the astrometric data from the Gaia DR2, we have identified 71 highly-probable member stars of the GD-1 cold stellar…

Spectral lines of hot massive stars are known to exhibit large excess broadening in addition to rotational broadening. This excess broadening is often attributed to macroturbulence whose physical origin is a matter of active debate in the…

Recent studies show that the Milky Way stellar halo is composed of populations of different origins, shaped by multiple accretion events. To better understand the formation of the Milky Way and other spiral galaxies, we characterize the…

The kinematic parameters identified from high-velocity stars situated within 100 kpc are examined and analyzed. We included three high velocity programs comprising 591, 87, and 519 stars as a function of distances ranging from 0.10 to…

Using new continuum and molecular line data from the ALMA Three-millimeter Observations of Massive Star-forming Regions (ATOMS) survey and archival VLA, 4.86 GHz data, we present direct observational evidence of hierarchical triggering…