Method for tilt correction of calibration lines in high resolution spectra

TL;DR

This paper introduces a post-processing method to correct curvature and tilt artifacts in high-resolution astronomical spectra, improving calibration accuracy and spectral analysis.

Contribution

A novel post-processing technique for tilt and curvature correction in high-resolution spectra, enhancing wavelength calibration and spectral fidelity.

Findings

Effective correction demonstrated on multiple spectrographs.

Improved accuracy in flux and line centroid measurements.

Applicable to various high-resolution spectroscopic instruments.

Abstract

Technological advancement has led to improvement in the design capabilities of astronomical spectrographs, allowing for high precision spectroscopy, thereby expanding the realms of observational astronomy. High-resolution spectrographs use Echelle grating that operates in higher orders, giving more detailed spectra. Often, curvature and tilted lines are observed in the spectra, arising due to the design trade-offs of the respective spectrographs. Removal of these artifacts can help avoid wrong flux calculation and line centroid position misinterpretation, which can aid in a better prediction of the wavelength calibration model. In this paper we present a post-processing technique that we developed to correct the observed curvature and tilt in the spectra. We have demonstrated the correction technique on Fabry-Perot and Th-Ar calibration spectra obtained from Hanle Echelle Spectrograph (HESP), Magellan Inamori Kyocera Echelle (MIKE) spectrometer and X-shooter spectrograph.