Related papers: Disk heating and stellar migration in galaxies
The existence of stellar cusps in dense clusters around massive black holes is a fundamental, decades-old prediction of theoretical stellar dynamics. Yet, observational evidence has been difficult to obtain. With a new, improved analysis of…
We investigate the role of radial migration history of stars in chemical evolution of a disk galaxy, in particular in understanding the origin of their bimodal distribution on the [alpha/Fe]-[Fe/H] plane. For this purpose, we examine the…
We re-examine the age-velocity dispersion relation in the solar neighborhood using improved stellar age estimates that are based on Hipparcos parallaxes and recent stellar evolution calculations. The resulting relation shows that the Milky…
We investigate gravitational lensing by a realistic model of disk galaxies. Most of the mass is contained in a large spherical isothermal dark matter halo, but the potential is modified significantly in the core by a…
Bars and spiral arms have played an important role as constraints on the dynamics and on the distribution of dark matter in the optical parts of disk galaxies. Dynamics linked to the dissipative nature of gas, and its transformation into…
As stars traverse the Milky Way, their orbits evolve through perturbations that alter their orbital radii. These changes arise from two mechanisms: churning, which modifies angular momentum, and blurring, which induces eccentric orbits…
Within the standard hierarchical structure formation scenario, Milky Way-mass dark matter haloes have hundreds of dark matter subhaloes with mass $\gtrsim 10^8 \, {\rm M_{\odot}}$. Over the lifetime of a galactic disc a fraction of these…
We study the vertical heating and thickening of galaxy disks due to accretion of small satellites. Our simulations are restricted to axial symmetry, which largely eliminates numerical evolution of the target galaxy but requires the…
Circumstellar disks are an essential ingredient of the formation of low-mass stars. It is unclear, however, whether the accretion-disk paradigm can also account for the formation of stars more massive than about 10 solar masses, in which…
The hot gaseous halos of galaxies likely contain a large amount of mass and are an integral part of galaxy formation and evolution. The Milky Way has a 2e6 K halo that is detected in emission and by absorption in the OVII resonance line…
Numerical simulations have revealed the presence of long-lived substructure in Cold Dark Matter (CDM) halos. These surviving cores of past merger and accretion events vastly outnumber the known satellites of the Milky Way. This finding has…
Recent numerical simulations have demonstrated that the Sun's dynamical history within the Milky Way may be much more complex than that suggested by its current low peculiar velocity. In particular, the Sun may have radially migrated…
The Milky Way disc presents a warp, a flare, lopsidedness and other deviations from a purely axisymmetrical double exponential density component, both for the stellar and the gas component. Moreover, recent large-scale extended kinematics…
Stars born on near-circular orbits in spiral galaxies can subsequently migrate to different orbits due to interactions with non-axisymmetric disturbances within the disc such as bars or spiral arms. This paper extends the study of migration…
A planetary system may undergo significant radial rearrangement during the early part of its lifetime. Planet migration can come about through interaction with the surrounding planetesimal disk and the gas disk--while the latter is still…
A massive planet in a protoplanetary disc will open a gap in the disc material which acts as a transition between Type I and Type II planetary migration. Type II migration is slower than Type I migration, however it is still desirable to…
The two papers referred to in the title, claiming the detection of a large-scale massive hot gaseous halo around the Galaxy, have generated a lot of confusion and unwarranted excitement (including public news coverage). However, the papers…
The kinematic dispersions of disc stars can be used to measure the dynamic contributions of baryons to the rotation curves of spiral galaxies and hence to trace the amount and distribution of the remaining dark matter. However, the simple…
After their initial formation, disk galaxies are observed to be rotationally stable over periods of >6 Gyr, implying that any large velocity disturbances of stars and gas clouds are damped rapidly on the timescale of their rotation.…
We investigate models of the Milky Way disc taking into account simultaneously the bar and a two-armed quasi-static spiral pattern. Away from major resonance overlaps, the mean stellar radial motions in the plane are essentially a linear…