Gemini GNIRS Longslit Reduction

Overview

The Gemini Near-Infrared Spectograph (GNIRS) was commissioned in 2004 by the Gemini Observatory. With coverage of 1–5$\mu$m, it remains a work-horse facility instrument on the Gemini North telescope in Hawai`i.

Recently, I used this instrument to obtain near-infrared spectra for low-mass galaxies at $z\approx0.8$. I learned that while Gemini has provided an IRAF reduction pipeline, automated implementation of this pipeline has been limited. For example, this website provided a number of tutorials, but ultimately the user needed to create scripts to execute, as this example script demonstrates. While Gemini recently released the DRAGONS Python-based data reduction pipeline, reduction is limited to imaging data.

The Automation Pipeline

With spectra taken on several dozens of nights, automation was critical to expedite data reduction for my project. Thus, I created a Python/PyRAF pipeline that used the existing Gemini IRAF package. This automation pipeline is made publicly available on GitHub and distributed under an MIT License. Because of the dependence on PyRAF/IRAF, this code is only compatible with Python 2.7.

The pipeline has several features:

• Longslit target acquisition checks with quality assurance (QA) visualization
• Correct detector readout artefacts with CLEANIR routine
• Flat fielding
• Wavelength calibration
• Dithered stacking
• Telluric flux calibration
• Spectral extraction

Installation

Installation is best done by cloning the GitHub repository and installing PyRAF.

This page is under construction. Stay tuned!