Searching for OVI Absorptions in DESI EDR Quasars

Collaborators: Siwei Zou (Tsinghua University, now NAOC), Zechang Sun (Tsinghua University)

We conduct a search for the strong OVI absorptions related with damped Lyman-\(\alpha\) systems from DESI EDR high S/N, $z\sim 2.5$ quasar spectra.

1. We normalize the quasar continuum with a unsupervised machine learning method (Sun et al. 2023) and achieve a great result (Figure 1). .
2. We visually inspect ~2500 normalized spectra and find ~30 OVI systems that are correlated with DLA systems (Figure 2).
3. We jointly fit the Voigt profile with other metal absorbers (Figure 3).
4. We estimate the contamination from Ly\(\alpha\) forest from mock spectra (Figure 4)
5. We conduct cloudy simulations to probe the ionization state of absorbers (no figure ☹ )