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We present results from two 1536^3 direct numerical simulations of rotating turbulence where both energy and helicity are injected into the flow by an external forcing. The dual cascade of energy and helicity towards smaller scales observed…

Fluid Dynamics · Physics 2015-05-14 P. D. Mininni , A. Pouquet

The evolution of the non-thermal emission emitted by pulsar wind nebulae is generally calculated using spatially-independent particle transport models. Although useful, these models implicitly assume that the source of non-thermal particles…

High Energy Astrophysical Phenomena · Physics 2013-08-09 Michael Vorster , Harm Moraal

We present a new perspective on the symmetries that govern the formation of large-scale structures across the Universe, particularly focusing on the transition from the seeds of galaxy clusters to the seeds of galaxies themselves. We…

Cosmology and Nongalactic Astrophysics · Physics 2024-03-28 Giovanni Montani , Nakia Carlevaro

In this methodological note we discuss some details and peculiarities of the cosmic expansion as viewed by a realistic observer. We show that the velocity $v_\Theta$ related to a change (measured by observer's clock) of the angular…

Popular Physics · Physics 2015-06-17 A. V. Toporensky , S. B. Popov

The increasing precision in the determination of the Hubble parameter has reached a per cent level at which large-scale cosmic flows induced by inhomogeneities of the matter distribution become non-negligible. Here we use large-scale…

Cosmology and Nongalactic Astrophysics · Physics 2017-06-28 Radoslaw Wojtak , Alexander Knebe , William A. Watson , Ilian T. Iliev , Steffen Hess , David Rapetti , Gustavo Yepes , Stefan Gottloeber

We present 3D hydrodynamical simulations of a jet launched from the secondary star of a binary system inside a proto-planetary nebula. The secondary star moves around the primary in a close eccentric orbit. From the gasdynamic simulations…

Solar and Stellar Astrophysics · Physics 2015-05-13 Sinhue A. R. Haro-Corzo , Pablo F. Velazquez , Alejandro C. Raga , Angels Riera , Primoz Kajdic

We present an analysis of the gas dynamics of star-forming galaxies at z~1.5 using data from the KMOS Galaxy Evolution Survey (KGES). We quantify the morphology of the galaxies using $HST$ CANDELS imaging parametrically and…

We compute, including a current state-of-the-art treatment of hydrodynamical processes, heating and cooling, a variety of cosmological models into the extreme nonlinear phase to enable comparisons with observations. First, we note the…

Astrophysics · Physics 2009-10-28 Jeremiah P. Ostriker , Renyue Cen

Numerous experimental and computational studies show that continuous hopper flows of granular materials obey the Beverloo equation that relates the volume flow rate $Q$ and the orifice width $w$: $Q \sim (w/\sigma_{\rm avg}-k)^{\beta}$,…

Soft Condensed Matter · Physics 2023-01-18 Y. Cheng , J. D. Treado , B. Lonial , P. Habdas , E. R. Weeks , M. D. Shattuck , C. S. O'Hern

We investigated the dynamics of highly turbulent thermally driven anabatic (upslope) flow on a physical model inside a large water tank using particle image velocimetry (PIV) and a thermocouple grid. The results showed that the flow…

Fluid Dynamics · Physics 2023-10-02 Roni H. Goldshmid , Dan Liberzon

New examples of harmonic unit vector fields on hyperbolic 3-space are constructed by exploiting the reduction of symmetry arising from the foliation by horospheres. This is compared and contrasted with the analogous construction in…

Differential Geometry · Mathematics 2007-12-31 C. M. Wood

Decaying three-dimensional (3D) turbulence is studied via direct numerical simulations (DNS) for an isotropic non-rotating flow and for rotating flows with and without helicity. We analyze the cases of moderate Rossby number and large…

Fluid Dynamics · Physics 2015-05-14 T. Teitelbaum , P. D. Mininni

The bipolar collimated outflows of the Hb4 Planetary Nebula (PN) exhibit an evident decrease in their expansion velocity with respect to the distance from the central star. So far, similar velocity law has also been found in Herbig-Haro…

Solar and Stellar Astrophysics · Physics 2019-02-13 Sophia Derlopa , Stavros Akras , Panos Boumis , Wolfgang Steffen

Turbulence plays an important role in shaping the interstellar medium, and strongly influences star formation. We aim to identify the physical processes capable of sustaining HI turbulence in the solar neighborhood. We compare recent HI…

In this paper, we consider the Universe deep inside of the cell of uniformity. At these scales, the Universe is filled with inhomogeneously distributed discrete structures (galaxies, groups and clusters of galaxies), which disturb the…

Cosmology and Nongalactic Astrophysics · Physics 2012-09-25 Maxim Eingorn , Alexander Zhuk

We present high-dispersion echelle spectroscopic observations and a narrow-band [N II] image of the remarkable jet-like features of He 2-90. They are detected in the echelle spectra in the H-alpha and [N II] lines but not in other nebular…

Using a code that employs a self-consistent method for computing the effects of photo-ionization on circumstellar gas dynamics, we model the formation of wind-driven nebulae around massive stars. We take into account changes in stellar…

Solar and Stellar Astrophysics · Physics 2022-02-22 Vikram V. Dwarkadas

The phenomenon of the very local ($\le3$ Mpc) Hubble flow is studied on the basis of the data of recent precision observations. A set of computer simulations is performed to trace the trajectories of the flow galaxies back in time to the…

The question of the relative importance of coherent structures and waves has for a long time attracted a great deal of interest in astrophysical plasma turbulence research, with a more recent focus on kinetic scale dynamics. Here we utilize…

Plasma Physics · Physics 2019-08-30 D. Groselj , C. H. K. Chen , A. Mallet , R. Samtaney , K. Schneider , F. Jenko

Recent observational constraints restrict the strict applicability of stellar dynamics in spirals to a few rotation periods. However, stellar dynamics concepts such as periodic orbits are invaluable for understanding the various dynamical…

Astrophysics · Physics 2008-02-03 D. Pfenniger
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