The Effect of Adiabatic Compression on Dark Matter Halos and the Radial Acceleration Relation

The Formation of Spiral Galaxies: Adiabatic Compression with Young's Algorithm and the Relation of Dark Matter Haloes to Their Primordial Antecedents

We utilize Young's algorithm to model the adiabatic compression of the dark matter haloes of galaxies in the THINGS survey to determine the relationship between the halo fit to the rotation curve and the corresponding primordial halo prior to compression. Young's algorithm conserves radial action and angular momentum, resulting in less halo compression than more widely utilized approximations. We find that estimates of the parameters of the NFW haloes fit to the current dark matter distribution systematically overestimate the concentration and underestimate the virial velocity of the correspon…

Low star formation efficiency due to turbulent adiabatic compression in the Taffy bridge

The Taffy system (UGC 12914/15) consists of two massive spiral galaxies which had a head-on collision about 20 Myr ago. New sensitive, high-resolution CO(1-0) observations of the Taffy system with the IRAM PdBI are presented. About 25% of the total interferometric CO luminosity stems from the bridge region. Assuming a Galactic N(H2)/ICO conversion factor for the galactic disks and a third of this value for the bridge gas, about 10% of the molecular gas mass is located in the bridge region. The giant HII region close to UGC 12915 is located at the northern edge of the high-surface brightness gi…

A lower bound on adiabatic heating of compressed turbulence for simulation and model validation

The energy in turbulent flow can be amplified by compression, when the compression occurs on a timescale shorter than the turbulent dissipation time. This mechanism may play a part in sustaining turbulence in various astrophysical systems, including molecular clouds. The amount of turbulent amplification depends on the net effect of the compressive forcing and turbulent dissipation. By giving an argument for a bound on this dissipation, we give a lower bound for the scaling of the turbulent velocity with compression ratio in compressed turbulence. That is, turbulence undergoing compression wil…

Stars Crushed by Black Holes. II. A Physical Model of Adiabatic Compression and Shock Formation in Tidal Disruption Events

We develop a Newtonian model of a deep tidal disruption event (TDE), for which the pericenter distance of the star, $r_{\rm p}$, is well within the tidal radius of the black hole, $r_{\rm t}$, i.e., when $β\equiv r_{\rm t}/r_{\rm p} \gg 1$. We find that shocks form for $β\gtrsim 3$, but they are weak (with Mach numbers $\sim 1$) for all $β$, and that they reach the center of the star prior to the time of maximum adiabatic compression for $β\gtrsim 10$. The maximum density and temperature reached during the TDE follow much shallower relations with $β$ than the previously predicted $ρ_{\rm max} …

绝热压缩的波暗物质晕与中等质量比旋近

Adiabatically compressed wave dark matter halo and intermediate-mass ratio inspirals

本文研究波暗物质晕在中心黑洞绝热增长下的压缩效应，发现压缩后密度显著增强并影响中等质量比旋近的引力波相位，为未来引力波探测重建波暗物质晕提供依据。

Evolution of Magnetic Fields and Cosmic Ray Acceleration in Supernova Remnants

Observations show that the magnetic field in young supernova remnants (SNRs) is significantly stronger than can be expected from the compression of the circumstellar medium (CSM) by a factor of four expected for strong blast waves. Additionally, the polarization is mainly radial, which is also contrary to expectation from compression of the CSM magnetic field. Cosmic rays (CRs) may help to explain these two observed features. They can increase the compression ratio to factors well over those of regular strong shocks by adding a relativistic plasma component to the pressure, and by draining the…