Investigation of Residual Blaze Functions in Slit-Based Echelle Spectrograph

TL;DR

This study analyzes residual blaze functions in slit-based echelle spectrographs, proposing a method to improve spectral order merging and continuum estimation by fitting a global response function, enhancing data reduction accuracy.

Contribution

Introduces a semiautomatic fitting method to eliminate target-dependent effects in residual blaze functions, improving spectral data quality.

Findings

Enhanced continuum estimation for spectra with wide, shallow lines

More reliable merging of spectral orders into a continuous spectrum

Reduction of target and observation condition dependencies

Abstract

We have studied the Residual Blaze Functions (RBF) resulting from division of individual echelle orders by extracted flat-field in spectra obtained by slit-fed OES spectrograph of 2m telescope of Ond\v{r}ejov observatory, Czech Republic. We have eliminated the dependence on target and observation conditions by semiautomatic fitting of global response function, thus getting the instrument-only dependent part, which may be easily incorporated into data reduction pipeline. The improvement of reliability of estimation of continuum on spectra of targets with wide and shallow lines is noticeable and the merging of all orders into the one long spectrum gives much more reliable results.