Marie Curie fellow at the Niels Bohr Institute

Stream evolution model

The 3D visualizations below are obtained from the semi-analytical model presented in this paper that describes the evolution of the stellar debris around the black hole following a tidal disruption event. In the first three, the black hole mass and penetration factor are fixed to Mh = 106 M⦿ and β=1. However, different shock radiative efficiencies are adopted from 1-ηsh=10-5 (first movie) to 10-3 (second movie) and 10-1 (third movie). In the last two movies, the shock radiative efficiency is fixed to 1-ηsh=10-3. Instead, the penetration factor is increased to β=2 (fourth movie) and the black hole mass is decreased to Mh = 5x105 M⦿ (fifth movie).

The movies end when the stream circularizes or when it becomes so wide that it entirely encompasses the black hole into a spherical envelope. The colors denote the width of the stream from its lowest value (white) to its largest value (blue). In all cases, an isometric view is adopted with the limits set such that the initial stream appears of the same length. Similarly, the initial stream period is imposed to be constant (of ten seconds). In reality, a tail of debris continues to fall back towards the black hole as the stream evolves. However, this tail is not shown here for sake of clarity.

For the interested reader, these visualizations have been produced using Mayavi2 in combination with MoviePy. A well-explained tutorial can be found here.

1. Largest shock radiative efficiency: the stream remains thin until it reaches circularization.

2. Intermediate shock radiative efficiency: the stream slowly thickens until it completely surrounds the black hole.

3. Lowest shock radiative efficiency: the stream rapidly puffs up to form an envelope entirely encompassing the black hole.

4. Larger penetration factor: the stream evolves faster into an small envelope.

5. Lower black hole mass: the stream evolves slower into a large envelope.