ZAP -- Enhanced PCA Sky Subtraction for Integral Field Spectroscopy

TL;DR

ZAP is a PCA-based sky subtraction method for integral field spectroscopy that effectively reduces residuals while preserving source flux and line shapes across various observational scenarios.

Contribution

The paper introduces ZAP, a novel PCA-based sky subtraction technique with filtering and segmentation, improving residual reduction and applicability for different observational contexts.

Findings

Reduces sky emission residuals effectively

Preserves flux and line shapes of sources

Applicable to diverse observational situations

Abstract

We introduce Zurich Atmosphere Purge (ZAP), an approach to sky subtraction based on principal component analysis (PCA) that we have developed for the Multi Unit Spectrographic Explorer (MUSE) integral field spectrograph. ZAP employs filtering and data segmentation to enhance the inherent capabilities of PCA for sky subtraction. Extensive testing shows that ZAP reduces sky emission residuals while robustly preserving the flux and line shapes of astronomical sources. The method works in a variety of observational situations from sparse fields with a low density of sources to filled fields in which the target source fills the field of view. With the inclusion of both of these situations the method is generally applicable to many different science cases and should also be useful for other instrumentation. ZAP is available for download at http://muse-vlt.eu/science/tools.