Clustering of high-redshift quasars with DESI DR2

arXiv:2606.27115 · astro-ph.CO · Submitted 2026-06-25 · Read on arXiv

M. Charles, P. Martini, A. J. Ross, D. H. Weinberg, J. Aguilar, S. Ahlen, D. Bianchi, D. Brooks, F. J. Castander, T. Claybaugh, A. Cuceu, A. de la Macorra, P. Doel, S. Ferraro, A. Font-Ribera, J. E. Forero-Romero, S. Gontcho A Gontcho, G. Gutierrez, J. Guy, C. Hahn, H. K. Herrera-Alcantar, K. Honscheid, C. Howlett, M. Ishak, R. Joyce, D. Kirkby, A. Kremin, M. Landriau, L. Le Guillou, M. E. Levi, M. Manera, A. Meisner, R. Miquel, J. Moustakas, A. D. Myers, S. Nadathur, N. Palanque-Delabrouille, W. J. Percival, F. Prada, I. Pérez-Ràfols, G. Rossi, L. Samushia, E. Sanchez, D. Schlegel, M. Schubnell, D. Sprayberry, G. Tarlé, B. A. Weaver, R. Zhou

astro-ph.CO

Submitted: 2026-06-25

Comments: 44 pages, 15 figures

License: http://creativecommons.org/licenses/by/4.0/

The gist: We present clustering measurements for high-redshift quasars using data from the Dark Energy Spectroscopic Instrument Data Release 2.

Terminology

Abstract

We present clustering measurements for high-redshift quasars using data from the Dark Energy Spectroscopic Instrument Data Release 2. Our sample consists of quasars with 2.0 < z < 3.5 in the luminosity range M 1450 at most-19.94,mag. We measure the mean quasar bias b Q(= 2.48) = 3.61 plus or minus 0.01 for the full sample of about 715,000 quasars and quantify the redshift evolution of quasar bias by dividing the sample into four equal redshift bins. There is strong evolution of the quasar bias with redshift that is well fit by the function b Q(z) = a [(1 + z) squared - 6.565] + b with a=0.230 plus or minus 0.007 and b=2.394 plus or minus 0.035, and this fit is also a good match to lower redshift measurements in the literature. This bias evolution is consistent with a characteristic halo mass of h about 10 12, M that does not vary significantly with redshift. The inferred duty cycles for quasars in our sample are f duty about 10-2, staying mostly constant over redshifts. We investigate the luminosity dependence of quasar clustering by dividing each of our four redshift bins into three luminosity bins. The size of our quasar sample permits the first statistically significant measurement of the luminosity dependence of quasar bias at these redshifts. We measure weak dependence of quasar bias on luminosity at fixed redshift, inconsistent with no dependence, but weaker than predicted by a model in which quasar luminosity is tightly correlated with halo mass. These clustering measurements provide a stringent test for models of active black hole light curves and the black hole-halo connection at high redshift.

Sources

Related papers