This repository contains the first-stage workflow for assessing sky-subtraction effects on DESI emission-line measurements, with a focus on narrow-line AGN spectra and the impact of sky residuals near the [OI] 6300/6364 Å region.
Night-sky emission introduces strong background features into ground-based optical spectroscopy. In emission-line studies, imperfect sky subtraction can affect line flux measurements, line ratios, and the physical interpretation of spectra.
This project focuses on evaluating how sky-subtraction residuals may influence DESI emission-line measurements, especially for narrow-line AGN spectra in the redshift range z = 0.25–0.29, where the target spectral features are close to important sky-line regions.
The current goal is to assess the effect of sky subtraction around the oxygen sky-line region near 6300 Å and 6364 Å, and to understand how these residuals may bias emission-line measurements in DESI spectra.
I reviewed the physical origin of night-sky background and the role of strong atmospheric emission lines in optical spectroscopy.
I defined the current science task as:
- using a narrow-line AGN sample at z = 0.25–0.29
- assessing the effect of sky subtraction near the [OI] sky-line region
- understanding the influence on emission-line measurements
I completed the first-stage notebook workflow, including:
- environment check
- inspection of DESI FITS files
- retrieval of public DESI spectra
- preliminary spectral exploration
desi-sky-subtraction-analysis/
├── docs/ # task summaries and progress notes
├── src/ # notebooks and scripts
├── figures/ # selected spectra and skyline-region plots
├── results/ # stage summaries and future outputs