PeX 1. Multi-spectral expansion of residual speckles for planet detection

TL;DR

This paper introduces a physically grounded multi-spectral model for residual speckle estimation in coronographic images, significantly improving exoplanet detection by reducing stellar leakage.

Contribution

It presents a novel multi-spectral diffraction-based model for residual speckle removal, suitable for inverse methods and applicable to real and simulated data.

Findings

Successfully estimates speckles in simulated data

Achieves high contrast in exoplanet detection

Effectively removes speckles from real SPHERE IFS data

Abstract

The detection of exoplanets in coronographic images is severely limited by residual starlight speckles. Dedicated post-processing can drastically reduce this "stellar leakage" and thereby increase the faintness of detectable exoplanets. Based on a multi-spectral series expansion of the diffraction pattern, we derive a multi-mode model of the residuals which can be exploited to estimate and thus remove the residual speckles in multi-spectral coronographic images. Compared to other multi-spectral processing methods, our model is physically grounded and is suitable for use in an (optimal) inverse approach. We demonstrate the ability of our model to correctly estimate the speckles in simulated data and demonstrate that very high contrasts can be achieved. We further apply our method to removing speckles from a real data cube obtained with the SPHERE IFS instrument.