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We present numerical simulations of gravito-inertial waves propagating in radiative zones of rapidly rotating stars. A first model, using the Boussinesq approximation, allows us to study the oscillations of a quasi-incompressible stratified…
The scenario of galaxy formation is believed to follow a structure that builds up from the bottom, with large galaxies being formed by several merging episodes of smaller ones. In this scenario a number of galaxies can be expected to be…
We present the results of a numerical magnetohydrodynamic simulation that demonstrates a mechanism by which magnetic fields tap rotational energy of a stellar core and expel the envelope. Our numerical setup, designed to focus on the basic…
Precessing Gamma Jets, originated by Neutron Stars or Black Holes, may blaze to the observer leading to Gamma Bursts (GRBs) and Soft Gamma repeaters (SGRs). The thin gamma jet is born either at Supernova (SN) like events mostly at the…
High-resolution numerical simulations of galaxy mergers are analysed. The global structure and isophotal shapes of the merger remnants are in good agreement with the observations. Whereas equal-mass mergers lead to anisotropic, boxy…
Rotation in massive stars has been studied on the main sequence and during helium burning for decades, but only recently have realistic numerical simulations followed the transport of angular momentum that occurs during more advanced stages…
Star quakes and internal phase transitions within anomalous x-ray pulsars (AXPs) and soft $\gamma$-ray repeaters (SGRs) can produce mini contractions and pulsar glitches. Shocks break out from their surface following such contractions…
In the collapsar model for common gamma-ray bursts, the formation of a centrifugally supported disk occurs during the first $\sim$10 seconds following the collapse of the iron core in a massive star. This only occurs in a small fraction of…
The structural properties of elliptical galaxies are consistent with their formation in a merging hierarchy. In this picture, the role of gaseous processes and dissipation decreased with increasing mass creating preferentially rotationally…
Binary neutron stars in circular orbits can be modeled as helically symmetric, i.e., stationary in a rotating frame. This symmetry gives rise to a first integral of the Euler equation, often employed for constructing equilibrium solutions…
Elliptical instability is due to a parametric resonance of two inertial modes in a fluid velocity field with elliptical streamlines. This flow is a simple model of the motion in a tidally deformed, rotating body. Elliptical instability…
The tidally tilted pulsators are a new type of oscillating star in close binary systems that have their pulsation axis in the orbital plane because of the tidal distortion caused by their companion. We describe this group of stars on the…
Core collapse supernovae(SN) are the final stages of evolution in massive stars during which the central region collapses. Recent explosion scenarios assumed that the ejection is due to energy deposition by neutrinos into the envelope but…
We study the dynamical evolution of a phase-transition-induced collapse neutron star to a hybrid star, which consists of a mixture of hadronic matter and strange quark matter. The collapse is triggered by a sudden change of equation of…
Extreme Scattering Events are radio-wave lensing events caused by AU-sized concentrations of ionised gas. Although they were discovered more than a decade ago we still have no clear picture of the physical nature of the lenses. To…
The very first stars in the Universe can be very massive, up to $10^3M_\odot$. If born in large numbers, such massive stars can have strong impact on the subsequent star formation, producing strong ionising radiation and contaminating the…
This review focuses on how galaxies and their globular cluster systems form. I first discuss the now fairly convincing evidence that some globular clusters form in galaxy starbursts/mergers. One way these observations are valuable is they…
Theoretically, stars have been formed from the collapse of cores in the molecular clouds. Historically, the core had been assumed as an singular isothermal sphere (SIS), and the collapse had been investigated by a self-similar manner. This…
Magnetic storms on stars manifest as remarkable, randomly occurring changes of the luminosity over durations that are tiny in comparison to the normal evolution of stars. These stellar flares are bursts of electromagnetic radiation from…
The unparalleled photometric data obtained by NASA's Kepler Space Telescope has led to improved understanding of red-giant stars and binary stars. We discuss the characterization of known eccentric system, containing a solar-like…