Unveiling the Diversity of [OII] Profiles of DESI Emission Line Galaxies and its Links to Star-formation and Morphology

Ting-Wen Lan^1*

¹Graduate Institute of Astrophysics, National Taiwan University, Taipei, Taiwan

* Presenter:Ting-Wen Lan, email:twlan@ntu.edu.tw

Star-forming galaxies that produce strong [OII] emission lines (emission-line galaxies, ELGs) have been considered and observed as one of the key targets for ongoing and upcoming cosmological surveys. For example, millions of ELG spectra have been collected by the Dark Energy Spectroscopic Instrument (DESI) survey. To fully maximize the scientific returns from such an enormous dataset for both cosmology and galaxy science, it is crucial to better understand the spectral and physical properties of ELGs. In this talk, I will show that DESI ELGs exhibit diverse emission line profiles, which can be classified into different types via Principal Component Analysis. Moreover, by combining the COSMOS dataset, we find that the line profiles of DESI ELGs correlate with the star-formation rate and morphology of galaxies, providing insights into the nature of DESI ELGs. Finally, I will discuss possible physical mechanisms that could give rise to the observed correlation, as well as the implications of our findings for recent ELG-dark matter halo connection results.

Keywords: Galaxy spectroscopy, Emission line galaxies, Principal component analysis