Related papers: The First Hypervelocity Star from the LAMOST Surve…

Context: Hyper-velocity stars move so fast that only a supermassive black hole (SMBH) seems to be capable to accelerate them. Hence the Galactic centre (GC) is their only suggested place of origin. Edelmann et al. (2005) found the early…

We study a sample of 43 early-type galaxies, selected from the SDSS because they appeared to have velocity dispersion > 350 km/s. High-resolution photometry in the SDSS i passband using HRC-ACS on board the HST shows that just less than…

In Data Release 9 of LAMOST, we present measurements of v sin i for a total of 121,698 stars measured using the Medium Resolution Spectrograph (MRS) and 80,108 stars using the Low Resolution Spectrograph (LRS). These values were obtained…

We have used infrared and radio observations to search for a dwarf galaxy associated with the high-velocity cloud (HVC) known as Complex H. Complex H is a large (> 400 deg^2) and probably nearby (d = 27 kpc) HVC whose location in the…

Recent Gaia observations suggest that some hypervelocity stars (HVSs) might originate from outside the Galaxy. We ask if these HVSs could come from as far as Andromeda. Therefore, we simulate HVSs originating in Andromeda with initial…

Hypervelocity stars (HVSs) escaping away from the Galactic halo are dynamical products of interactions of stars with the massive black hole(s) (MBH) in the Galactic Center (GC). They are mainly B-type stars with their progenitors unknown.…

Rotation and binary interaction play important roles in understanding the nature of massive stars (>8 Msun). Some interesting transients, such as the long-duration gamma-ray bursts, are thought to be originated from fast-rotating massive…

We report the first determination of the distance to the Galactic centre based on the kinematics of halo objects. We apply the statistical-parallax technique to the sample of ~2500 Blue Horizontal Branch (BHB) stars compiled by Xue et al.…

We present the germ of a new model for High Velocity Clouds, derived from the idea that the dark matter halo of our Galaxy is in the form of cold, planetary-mass gas clouds. In this picture HVCs arise as a result of disruptive collisions…

We report 23 stars having Galactocentric velocities larger than $450~\mathrm{km\,s}^{-1}$ in the final data release of the APOGEE survey. This sample was generated using space velocities derived by complementing the high quality radial…

The Galactic centre Nuclear Star Cluster is one of the densest stellar clusters in the Galaxy. The stars in its inner portions orbit the supermassive black hole associated with compact radio source Sgr~A* at the orbital speeds of several…

Hypervelocity stars (HVSs) are a natural consequence of the presence of a massive nuclear black hole (Sgr A*) in the Galactic Center. Here we use the Brown et al. sample of unbound and bound HVSs together with numerical simulations of the…

Utilizing astrometric parameters sourced from \textit{Gaia} Data Release 3 and radial velocities obtained from various spectroscopic surveys, we identify 519 high-velocity stars (HiVels) with a total velocity in the Galactocentric restframe…

In this paper, we investigate the link between the hypervelocity stars (HVSs) discovered in the Galactic halo and the S-stars moving in the Galactic center (GC), under the hypothesis that they are both the products of the tidal breakup of…

The hyper-velocity star S5-HVS1, ejected 5 Myr ago from the Galactic Center at 1800 km/s, was most likely produced by tidal break-up of a tight binary by the supermassive black hole SgrA*. Taking a Monte Carlo approach, we show that the…

We present an overview and a status report of HYPERMUCHFUSS (HYPER velocity or Massive Unseen Companions of Hot Faint Underluminious Stars Survey) aiming at the detection of a population of high velocity subluminous B stars and white…

We measure proper motions with the Hubble Space Telescope for 16 extreme radial velocity stars, mostly unbound B stars in the Milky Way halo. Twelve of these stars have proper motions statistically consistent with zero, and thus have radial…

We propose a new way to search for hypervelocity stars in the Galactic bulge, by using red clump (RC) giants, that are good distance indicators. The 2nd Gaia Data Release and the near-IR data from the VISTA Variables in the Via Lactea (VVV)…

We report the discovery of 15 stars in the H3 survey that lie, in projection, near the tip of the trailing gaseous Magellanic Stream (MS). The stars have Galactocentric velocities $< -155$ km s$^{-1}$, Galactocentric distances of $\approx…

Context: Hyper-velocity stars are suggested to originate from the dynamical interaction of binary stars with the supermassive black hole in the Galactic centre (GC), which accelerates one component of the binary to beyond the Galactic…