Cosmic Web to Spiral Disk Lab: Zel'dovich Collapse, NFW…

The Zel'dovich Approximation

The Zel'dovich approximation is a method used in cosmology to model the large-scale structure of the universe. It starts with small ripples in the density field, which grow over time due to gravitational attraction. This process, known as gravitational collapse, leads to the formation of structures like galaxy clusters and superclusters.

By applying this approximation, scientists can predict how these initial perturbations evolve into the cosmic web—a network of filaments and voids that permeates the universe.

NFW Halos

An NFW (Navarro-Frenk-White) halo is a model used to describe the density distribution of dark matter in galaxies. The NFW profile predicts that dark matter is concentrated at the center of a galaxy, with a characteristic scale radius and an asymptotic slope of -1.

This model helps explain why spiral galaxies have flat rotation curves far from their centers, despite the decrease in visible matter density.

live demo · related simulation● LIVE

Tidal-Torque Spin

The tidal-torque theory explains how a galaxy's spin is influenced by interactions with its environment. As a galaxy moves through the cosmic web, it experiences gravitational tides from nearby structures. These tides can transfer angular momentum to and from the galaxy, affecting its overall rotation.

This process is crucial for understanding why some galaxies are rotating rapidly while others have more chaotic motions.

Density Waves

Density waves in spiral galaxies are coherent patterns of density variations that propagate through the disk. These waves cause periodic compressions and rarefactions, leading to star formation and the shaping of spiral arms.

The Lindblad resonances associated with these waves determine where stars and gas can be trapped, influencing the structure and dynamics of the galaxy's disk.

Frequently asked questions

What does NFW stand for in the context of halos?

NFW stands for Navarro-Frenk-White, named after the scientists who developed this model to describe the density distribution of dark matter in galaxies.

How do tidal-torque effects influence galaxy rotation?

Tidal-torque effects can transfer angular momentum between a galaxy and its surroundings, altering the galaxy's spin. This process is essential for understanding the rotational properties of galaxies observed in the universe.

Why are density waves important in spiral galaxies?

Density waves are crucial because they drive star formation and shape the spiral structure of galaxies by compressing gas into denser regions, which then collapse to form new stars.

What is the significance of Lindblad resonances in galactic dynamics?

Lindblad resonances are key because they determine where stars and gas can be trapped in a galaxy's spiral arms. These resonances help explain the regular patterns observed in the rotation curves of galaxies.

Try it live

Everything above runs in your browser — open Cosmic Web to Spiral Disk Lab: Zel'dovich Collapse, NFW Halo, Tidal-Torque Spin and Density Wave and change the parameters while it is running. Nothing is installed, nothing is uploaded, the whole model lives in one tab.

▶ Open Cosmic Web to Spiral Disk Lab: Zel'dovich Collapse, NFW Halo, Tidal-Torque Spin and Density Wave simulation