DESI Emission-line Galaxies: Unveiling the Diversity of [O ii] Profiles and Its Links to Star Formation and Morphology

Lan, Ting-Wen; Prochaska, J. Xavier; Moustakas, John; Siudek, Małgorzata; Aguilar, J.; Ahlen, S.; Bianchi, D.; Brooks, D.; Claybaugh, T.; Cole, S.; Dawson, K.; de la Macorra, A.; Doel, P.; Forero-Romero, J. E.; Gaztañaga, E.; Gontcho A Gontcho, S.; Gutierrez, G.; Guy, J.; Honscheid, K.; Kehoe, R.; Kisner, T.; Lambert, A.; Landriau, M.; Meisner, A.; Miquel, R.; Muñoz-Gutiérrez, A.; Newman, J. A.; Poppett, C.; Prada, F.; Rossi, G.; Sanchez, E.; Schubnell, M.; Seo, H.; Sprayberry, D.; Tarlé, G.; Weaver, B. A.; Zou, H.

Abstract

We study the [O ii] profiles of emission-line galaxies (ELGs) from the Early Data Release of the Dark Energy Spectroscopic Instrument (DESI). To this end, we decompose and classify the shape of [O ii] profiles with the first two eigenspectra derived from principal component analysis. Our results show that DESI ELGs have diverse line profiles, which can be categorized into three main types: (1) narrow lines with a median width of ∼50 km s−1, (2) broad lines with a median width of ∼80 km s−1, and (3) two redshift systems with a median velocity separation of ∼150 km s−1, i.e., double-peak galaxies. To investigate the connections between the line profiles and galaxy properties, we utilize the information from the COSMOS data set and compare the properties of ELGs, including star formation rate (SFR) and galaxy morphology, with the average properties of reference star-forming galaxies with similar stellar mass, sizes, and redshifts. Our findings show that, on average, DESI ELGs have a higher SFR and more asymmetrical/disturbed morphology than the reference galaxies. Moreover, we uncover a relationship between the line profiles, the excess SFR, and the excess asymmetry parameter, showing that DESI ELGs with broader [O ii] line profiles have more disturbed morphology and higher SFR than the reference star-forming galaxies. Finally, we discuss possible physical mechanisms giving rise to the observed relationship and the implications of our findings on the galaxy clustering measurements, including the halo occupation distribution modeling of DESI ELGs and the observed excess velocity dispersion of the satellite ELGs.

Citation

Lan, T.-W., Prochaska, J. X., Moustakas, J., Siudek, M., Aguilar, J., Ahlen, S., Bianchi, D., Brooks, D., Claybaugh, T., Cole, S., Dawson, K., de la Macorra, A., Doel, P., Forero-Romero, J. E., Gaztañaga, E., Gontcho A Gontcho, S., Gutierrez, G., Guy, J., Honscheid, K., …Zou, H. (2024). DESI Emission-line Galaxies: Unveiling the Diversity of [O ii] Profiles and Its Links to Star Formation and Morphology. Astrophysical Journal, 977(2), 225. https://doi.org/10.3847/1538-4357/ad8f33

• Journal Article Type: Article
• Acceptance Date: Nov 4, 2024
• Online Publication Date: Dec 16, 2024
• Publication Date: Dec 20, 2024
• Deposit Date: Jan 22, 2025
• Publicly Available Date: Jan 22, 2025
• Journal: The Astrophysical Journal
• Print ISSN: 0004-637X
• Electronic ISSN: 1538-4357
• Publisher: American Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 977
• Issue: 2
• Article Number: 225
• DOI: https://doi.org/10.3847/1538-4357/ad8f33
• Public URL: https://durham-repository.worktribe.com/output/3346956