Related papers: On the radial velocity wave in the Galactic disk
Recent asteroseismic advances have allowed for direct measurements of the internal rotation rates of many sub-giant and red giant stars. Unlike the nearly rigidly rotating Sun, these evolved stars contain radiative cores that spin faster…
Nonaxisymmetric, meridional circulation inside a neutron star, excited by a glitch and persisting throughout the post-glitch relaxation phase, emits gravitational radiation. Here, it is shown that the current quadrupole contributes more…
In the $(\lambda_{\rm R}, \varepsilon)$ and $(V/\sigma, \varepsilon)$ diagrams for characterizing dynamical states, the fast-rotator galaxies (both early-type and spirals) are distributed within a well-defined leaf-shaped envelope. This was…
The role of gravitational instability-driven turbulence in determining the structure and evolution of disk galaxies, and the extent to which gravity rather than feedback can explain galaxy properties, remains an open question. To address…
An analysis of MHD wave propagating in a gravitating and rotating medium permeated by non-uniform magnetic field has been done. It has been found that the Gradient of Magnetic Field when coupled with Rotation becomes capable to generate few…
We introduce a new model for the structure and evolution of the gas in galactic discs. In the model the gas is in vertical pressure and energy balance. Star formation feedback injects energy and momentum, and non-axisymmetric torques…
We consider three samples of O- and B-type stars from the solar neighborhood 0.6--4 kpc for which we have taken the distances, line-of-sight velocities, and proper motions from published sources. The first sample contains 120 massive…
Glitches in pulsars are likely to trigger oscillation modes in the fluid interior of neutron stars. We examined these oscillations specifically at r-mode frequencies. The excited r-modes will emit gravitational waves and can have long…
We seek to understand the origin of radial migration in spiral galaxies by analyzing in detail the structure and evolution of an idealized, isolated galactic disk. To understand the redistribution of stars, we characterize the…
A satellite galaxy or dark matter subhalo that passes through a stellar disk may excite coherent oscillations in the disk perpendicular to its plane. We determine the properties of these modes for various self-gravitating plane symmetric…
The existence of a superfluid core in the interior of a rotating neutron star may have an influence on its gravitational wave emission. In addition to the usually-assumed pure quadrupole radiation with the gravitational wave frequency at…
We test the effect of assumptions about stellar motion on the behavior of gravitational instabilities in protoplanetary disks around solar-type stars by performing two simulations that are identical in all respects except the treatment of…
While galaxy rotation curves provide one of the most powerful methods for measuring dark matter profiles in the inner regions of rotation-supported galaxies, at the dwarf scale there are factors that can complicate this analysis. Given the…
A significant fraction of galaxies show warps in their discs, usually noticeable at its periphery. The exact origin of this phenomenon is not fully established, although multiple warp formation mechanisms are proposed. In this study, we…
Two classes of high energy sources in our galaxy are believed to host magnetars, neutron stars whose emission results from the dissipation of their magnetic field. The extremely high magnetic field of magnetars distorts their shape, and…
Non-axisymmetric components, such as spirals and central bars, play a major role in shaping galactic discs. An important aspect of the disc secular evolution driven by these perturbers is the radial migration of stars. It has been suggested…
Stars show various amounts of radial velocity (RV) jitter due to varying stellar activity levels. The typical amount of RV jitter as a function of stellar age and observational timescale has not yet been systematically quantified, although…
Circumstellar asymmetries such as central warps have recently been shown to cast shadows on outer disks. We investigate the hydrodynamical consequences of such variable illumination on the outer regions of a transition disk, and the…
Spiral patterns are important agents of galaxy evolution. In this review, I describe how the redistribution of angular momentum by recurrent transient spiral patterns causes the random speeds of stars to rise over time, metallicity…
Protoplanetary disks are mainly heated by radiation from the central star. Since the incident stellar flux at any radius is sensitive to the disk structure near that location, an unstable feedback may be present. Previous investigations…