Determination of astrometry and photometry of faint companions in the presence of residual speckle noise

¹ Applied Optics Group School of Physics National University of Ireland, Galway Ireland
² European Organisation for Astronomical Research in the Southern Hemisphere, Karl-Schwarzschild-Strasse 2, D-85748 Garching bei Munchen, Germany

^a e-mail: daniel.burke@nuigalway.ie

Abstract

In this paper we examine approaches to faint companion detection and estimation in multi-spectral images. We will employ the Hotelling observer which is the optimal linear algorithm for signal detection. We have shown how to use this observer to estimate faint object position and brightness in the presence of residual speckle which usually limit astrometric and photometric techniques. These speckles can be reduced by differential imaging techniques such as Angular Differential Imaging and Spectral Differential Imaging. Here we present results based on simulations of adaptive optics corrected images from an ELT which contain quasi-static speckle noise. The simulation includes Angular Differential Imaging to reduce the residual speckle and subsequent multi-wavelenght processing. We examine the feasibility of this approach on simulated ELT observations of faint companions.