# Polarimetry and strong gravity effects from spots orbiting near a black hole

## TL;DR

This paper investigates how the orbiting spot model predicts flux and polarization variations in black hole accretion, highlighting the impact of emission region geometry on observable signals.

## Contribution

It introduces the influence of emission region shape, such as spiral versus small spot, on flux and polarization modulations near black holes.

## Key findings

- Spiral-shaped emission regions produce distinct lightcurve signatures.
- Polarization degree and angle vary predictably with orbiting spots.
- Emission geometry can be distinguished through polarization measurements.

## Abstract

We study the modulation of the observed radiation flux and the associated changes in the polarization degree and angle that are predicted by the orbiting spot model for flares from accreting black holes. The geometric shape of the emission region influences the resulting model lightcurves, namely, the emission region of a spiral shape can be distinguished from a simpler geometry of a small orbiting spot.