The IRAC Distant Cluster Survey

Karolina Garcia; Anthony H. Gonzalez; Mark Brodwin; Peter Eisenhardt; Tyler George; Nadia Hansen; S. A. Stanford; Daniel Stern; Khunanon Thongkham; Ariane Trudeau; Michael J. I. Brown; Buell T. Jannuzi

arXiv · 2610.40534

The IRAC Distant Cluster Survey

Karolina Garcia·Anthony H. Gonzalez·Mark Brodwin·Peter Eisenhardt·Tyler George·Nadia Hansen·S. A. Stanford·Daniel Stern·Khunanon Thongkham·Ariane Trudeau·Michael J. I. Brown·Buell T. Jannuzi

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Abstract

We present the Infrared Array Camera (IRAC) Distant Cluster Survey (IDCS), a catalog of 825 galaxy cluster and group candidates identified in the Boötes field using the PZWav detection code. Candidates are selected using photometric redshift probability distributions derived from twelve-band optical and infrared imaging. The catalog spans $0.08 < z < 2.0$ (median $z = 0.93$) and includes 147 systems at $z \geq 1.5$. For $z < 1.5$, simulations indicate a purity of $93\%$ at the adopted S/N $\geq 4$ threshold and $50\%$ completeness at $\log(M_{200c}/M_\odot) = 13.74 \pm 0.01$. We validate the cluster photometric redshifts through comparison with spectroscopic data, finding $σ_z/(1+z)=0.017$. Including 18 previously published IRAC Shallow Cluster Survey (ISCS) systems, a total of 80 IDCS cluster candidates are now confirmed through spectroscopy and/or X-ray observations. DESI DR1 spectroscopy provides redshifts for 38 systems, including 23 newly confirmed clusters. These DESI-confirmed systems span $0.12 < z < 0.93$ and have at least 10 spectroscopic members each, from which we measure a median velocity dispersion of $\sim 490$ km s$^{-1}$, corresponding to a median halo mass of $1.1 \times 10^{14} M_\odot$. A positional comparison with 39 independently confirmed literature clusters yields a median centroid offset of 211 kpc. The IDCS catalog provides a cluster sample spanning a wide redshift range, with a selection function characterized through simulations and is a valuable resource for studies of large-scale structure, galaxy evolution in dense environments, and the calibration of cluster detection techniques for current and upcoming wide-field surveys, including LSST, Roman, and Euclid.

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Karolina Garcia, Anthony H. Gonzalez, Mark Brodwin, Peter Eisenhardt, Tyler George, Nadia Hansen, S. A. Stanford, Daniel Stern, Khunanon Thongkham, Ariane Trudeau, Michael J. I. Brown, Buell T. Jannuzi. 2026-10-29. The IRAC Distant Cluster Survey. https://arxiv.org/abs/2610.40534

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