Saurabh

Simulations

Black-hole images are computed before they are observed. These pages collect the simulations I work with, from a single orbiting hotspot to full GRMHD, and explain how they are made.

GuideHow to simulate black hole accretionGeodesics, ray tracing and observed intensity, explained step by step, with an interactive diagram of light bending around a black hole.

A ladder of models

Animated hotspot orbiting a Schwarzschild black hole — Orbiting hotspot. A compact blob of hot plasma on a circular orbit. Its primary and secondary images show how lensing delays and distorts a flare.

Animated thin disk seen at changing inclination — Novikov–Thorne thin disk. A geometrically thin, optically thick disk, viewed as the inclination sweeps around.

Animated ray-traced radiatively inefficient accretion flow — Semi-analytic RIAF. A hot, optically thin flow, closer to what feeds M87* and Sgr A*, and cheap enough to scan large parameter grids.

Animated GRMHD simulation of accretion onto a Schwarzschild black hole — GRMHD. Magnetized turbulent gas evolved self-consistently around a Schwarzschild black hole, then ray traced.