Galactic Dark Matter Halo: 2D Orbit Map

What is Dark Matter?

Dark matter is a form of matter that does not interact with light or any other electromagnetic radiation, making it invisible to telescopes. However, its presence can be inferred through its gravitational effects on visible matter and the overall dynamics of galaxies and galaxy clusters.

The concept of dark matter was first proposed in the 1930s by Swiss astronomer Fritz Zwicky, who observed that the mass of a cluster of galaxies must be much larger than what could be seen to account for the observed gravitational effects.

NFW Halo and Galactic Dynamics

The Navarro-Frenk-White (NFW) profile is a mathematical model used to describe the distribution of dark matter in galaxies. It predicts that dark matter density decreases with distance from the galactic center, but not as quickly as the inverse square law would suggest for a point mass.

In this 2D orbit map simulation, the NFW halo, along with the disk and bulge components, provides the gravitational potential that governs the orbits of stars within the galaxy.

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Tidal Stripping and Satellite Galaxies

When a smaller satellite galaxy approaches a larger one, tidal forces can strip away its outer layers, creating a stellar stream. This process is known as tidal disruption or tidal stripping.

In this simulation, launching a satellite galaxy into the gravitational well of the main galaxy demonstrates how these processes occur and how they contribute to the observed structure of galaxies.

Rotation Curve and Dark Matter Detection

The rotation curve of a galaxy shows the orbital speed of stars at different distances from the galactic center. In visible matter alone, this speed would decrease with distance due to the decreasing mass density. However, observations show that the rotational speeds remain constant or even increase, indicating the presence of dark matter.

By adjusting parameters in the simulation and observing changes in the rotation curve graph, one can explore how the distribution of dark matter affects stellar orbits.

Frequently asked questions

How does dark matter affect galaxy structure?

Dark matter provides the gravitational framework that shapes galaxies by influencing their overall mass distribution and thus the dynamics of visible stars. Its presence is inferred from the observed rotation curves and gravitational lensing effects.

What role does the NFW profile play in this simulation?

The NFW profile models the density distribution of dark matter within a galaxy, allowing us to understand how it affects the orbits of stars. It helps explain why galaxies rotate faster than expected based on visible matter alone.

Why do satellite galaxies get tidally stripped?

Satellite galaxies are tidally stripped due to the gravitational forces exerted by the larger galaxy they approach. These forces can stretch and pull material from the smaller galaxy, leading to the formation of stellar streams that trace the path of the disrupted satellite.

How does this simulation help in understanding dark matter?

This simulation provides a visual and interactive way to explore how dark matter influences galactic dynamics. By adjusting parameters and observing the resulting changes, one can gain insights into the complex interplay between visible stars, dark matter, and the overall structure of galaxies.

Try it live

Everything above runs in your browser — open Galactic Dark Matter Halo: 2D Orbit Map and change the parameters while it is running. Nothing is installed, nothing is uploaded, the whole model lives in one tab.

▶ Open Galactic Dark Matter Halo: 2D Orbit Map simulation