Understanding the light curves of the HST-1 knot in M87

TL;DR

This paper models the complex multi-wavelength light curves of the HST-1 knot in M87 using a semi-analytical approach based on periodic velocity oscillations, successfully reproducing observed features and also applying to a micro-quasar.

Contribution

It introduces a semi-analytical model that accurately reproduces the complex light curves of the HST-1 knot and a micro-quasar, advancing understanding of jet dynamics.

Findings

High-accuracy reproduction of HST-1 light curves across wavelengths

Model also successfully fits light curve of micro-quasar A06200-00

Supports shock wave interpretation with periodic velocity oscillations

Abstract

The motion of knots in astrophysical jets is commonly interpreted as shock waves moving along it. Observations of the HST-1 knot during extended periods of time have produced complicated light curves on many wavelengths which are difficult to account using standard hydrodynamical models. Here we reproduce these light curves using the semi-analytical approach developed by Mendoza et al. (2009), developed to reproduce light curves of working surfaces moving along relativistic jets. These working surfaces are generated by periodic oscillations of the injected flow velocity and discharge at the base of the jet. In particular, we use this approach to reproduce the exotic observed features of the light curves of the HST-1 knot in M87. We show that the complicated fits to the light curves are reproduced with high accuracy in all wavelengths. As a bonus, we show that this model is also able to reproduce the light curve of the micro-qsr A06200-00 with high accuracy.