In a recent study, a team of researchers led by Lucas Napolitano from the University of Illinois at Urbana-Champaign has constructed a composite spectrum of quasar absorption line systems using data from the Dark Energy Spectroscopic Instrument (DESI). The team, which includes scientists from various institutions, has identified over 70 absorption lines and observed oxygen and hydrogen emission features with unprecedented clarity.
Quasars, or quasi-stellar objects, are extremely luminous active galactic nuclei that emit vast amounts of energy. As the light from a distant quasar travels towards an observer, it may interact with the circumgalactic medium environment of an intervening galaxy, forming absorption lines. These absorption lines can provide valuable information about the composition and physical conditions of the intervening matter.
To maximize the signal of these absorption lines, the researchers selected a sample of 238,838 quasar spectra from the second data release of DESI. Each spectrum was identified to have absorption lines resulting from an interaction with the circumgalactic medium. By stacking these spectra in the restframe of the absorption and calculating a median composite spectrum, the researchers were able to isolate and enhance these absorption lines.
The resulting composite spectrum provides a detailed atlas of all detected absorption and emission lines, along with their fit centroids and equivalent width values. This atlas is expected to aid future studies investigating the compositions and physical conditions of these absorbers.
The practical applications of this research for the energy sector are not immediately apparent, as the study is primarily focused on astrophysics and cosmology. However, the techniques used to analyze and interpret the data could potentially be applied to other fields, such as spectroscopy and remote sensing, which are relevant to the energy industry. For example, the ability to isolate and enhance specific spectral features could be useful in the analysis of energy-related materials or the monitoring of environmental impacts.
The research was published in the Astrophysical Journal Supplement Series, a peer-reviewed scientific journal that publishes collections of astronomical data and software. The journal is widely regarded as a valuable resource for astronomers and astrophysicists, and the publication of this study is expected to contribute to the ongoing efforts to understand the composition and evolution of the universe.
This article is based on research available at arXiv.