Luminosity function of quasars at 1.0<z<3.5 from SDSS and DESI
Gaocheng Yin, Linhua Jiang, Zhiwei Pan, Paul Martini, Wei-Jian Guo, Siwei Zou, Shengxiu Sun, Swayamtrupta Panda, Abhijeet Anand, Benjamin Alan Weaver, Aaron Meisner, Andrei Cuceu, Arjun Dey, Axel de la Macorra, Christophe Magneville, David Brooks, David Kirkby, David Schlegel, David Sprayberry, Davide Bianchi, Dick Joyce, Enrique Gaztañaga, Eusebio Sanchez, Francisco Javier Castander, Francisco Prada, Gaston Gutierrez, Graziano Rossi, Gregory Tarlé, Hiram K. Herrera-Alcantar, Hu Zou, Ignasi Pérez-Ràfols, Jaime E. Forero-Romero, Jessica Nicole Aguilar, John Moustakas, Joseph Harry Silber, Klaus Honscheid, Laurent Le Guillou, Marc Manera, Martin Landriau, Michael Schubnell, Mustapha Ishak, Nathalie Palanque-Delabrouille, Peter Doel, Ramon Miquel, Robert Kehoe, Satya Gontcho A Gontcho, Seshadri Nadathur, Simone Ferraro, Stephanie Juneau, Steven Ahlen, Theodore Kisner, Todd Claybaugh, Will Percival, Anthony Kremin, Claire Lamman, Claire Poppett, Rongpu Zhou
astro-ph.GA
Submitted: 2026-08-06
Comments: 16 pages, 6 figures. Accepted for publication in The Astrophysical Journal
License: http://creativecommons.org/licenses/by/4.0/
The gist: We present a study of the evolution of type 1 quasars at 1.0<z<3.5, covering the peak epoch of quasar activity.
Terminology
Abstract
We present a study of the evolution of type 1 quasars at 1.0<z<3.5, covering the peak epoch of quasar activity. The quasar evolution has been extensively explored by a variety of previous works and the derived quasar luminosity functions (QLFs) are not well consistent with each other, presumably due to the complexities introduced by different quasar selection techniques and associated completeness corrections. We use a new strategy to construct QLFs based on a library of all known quasars. We focus on a wide region of about 1700 deg squared and a deep field of about 265 deg squared that have rich spectroscopic data primarily from SDSS and DESI. We then apply traditional color cuts in the rest-frame UV/optical to select quasar candidates and use the quasar library to identify them. Our final sample consists of 62,426 quasars at 1.0<z<3.5, with a high completeness (about 96%) and a high purity (about 93%) in the color selection. Simple color cuts can potentially minimize selection biases for the study of quasar evolution. We derive binned QLFs and characterize them using a double power-law model. Sample incompleteness and contamination are considered as part of the uncertainties in the calculation. Compared to previous results, our QLFs are slightly higher at the faint end, and also higher at the bright end at 2.5<z<3.5. The QLFs suggest that the quasar evolution at 1.0 < z < 2.5 can be well described by the pure luminosity evolution model, while at 2.5 < z < 3.5, it can be described by either the pure luminosity evolution or the pure density evolution model.
Sources
- Introduction to the Chinese Space Station Survey Telescope (CSST)
- The DESI Experiment Part II: Instrument Design
- DESI DR2 Results II: Measurements of Baryon Acoustic Oscillations and Cosmological Constraints
- Using Active Learning to Improve Quasar Identification for the DESI Spectra Processing Pipeline
- Quaia, the Gaia-unWISE Quasar Catalog: An All-Sky Spectroscopic Quasar Sample
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