September 10, 2025Open Access
View Full PaperThe Cosmic Evolution of C IV Absorbers at 1.4 z < 4.5: Insights from 100,000 Systems in DESI Quasars
Key Points
- The study identifies a total of 101,487 C IV absorbers within the specified redshift range.
- The cosmic mass density of C IV increases by a factor of approximately 3.8 from redshift z ≈ 4.5 to z ≈ 1.4.
- Weak redshift evolution is observed in the equivalent width frequency distribution of C IV absorbers.
- This catalog serves as a significant resource for future studies connecting metals to galaxy evolution.
Abstract
Abstract We present the largest catalog to date of triply ionized carbon (C iv ) absorbers detected in quasar spectra from the Dark Energy Spectroscopic Instrument. Using an automated matched-kernel convolution method with adaptive signal-to-noise thresholds, we identify 101,487 C iv systems in the redshift range 1.4 log ( Z IGM / Z ⊙ ) ≳ − 3.25 at z ∼ 2.3, with a smooth decline at higher redshifts. These trends trace the cosmic star formation history and He ii photoheating rate, suggesting a link between C iv enrichment, star formation, and UV background over ∼3 Gyr. The catalog also provides a critical resource for future studies connecting circumgalactic metals to galaxy evolution, especially near cosmic noon.