The Distribution of Quenched Galaxies in the Massive z = 0.87 Galaxy Cluster El Gordo

Rachel Honor; Seth Cohen; Timothy Carleton; Steven Willner; Maria del Carmen Polletta; Rogier Windhorst; Dan Coe; Christopher Conselice; Jose Diego; Simon Driver; Jordan D'Silva; Nicholas Foo; Brenda Frye; Norman Grogin; Nimish Hathi; Rolf Jansen; Patrick Kamieneski; Anton Koekemoer; Reagen Leimbach; Madeline Marshall; Rafael Ortiz III; Nor Pirzkal; Massimo Ricotti; Aaron Robotham; Michael Rutkowski; Russell Ryan; Payaswini Saikia; Jake Summers; Christopher Willmer; Haojing Yan

arXiv · 2510.08801

The Distribution of Quenched Galaxies in the Massive z = 0.87 Galaxy Cluster El Gordo

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Abstract

El Gordo (ACT-CL J0102$-$4915) is a massive galaxy cluster with two major mass components at redshift $z=0.87$. Using SED fitting results from JWST/NIRCam photometry, the fraction of quenched galaxies in this cluster was measured in two bins of stellar mass: $9<\log{({M_*}/\mathrm{M}_{\odot})}<10$ and $10\leq\log{({M_*}/\mathrm{M}_{\odot})}<12$. While there is no correlation between the quenched fraction and angular separation from the cluster's overall center of mass, there is a correlation between the quenched fraction and angular separation from the center of the nearest of the two mass components for the less-massive galaxies. This suggests that environmental quenching processes are in place at $z\sim1$, and that dwarf galaxies are more affected by those processes than massive galaxies.

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Rachel Honor, Seth Cohen, Timothy Carleton, Steven Willner, Maria del Carmen Polletta, Rogier Windhorst, Dan Coe, Christopher Conselice, Jose Diego, Simon Driver, Jordan D'Silva, Nicholas Foo, Brenda Frye, Norman Grogin, Nimish Hathi, Rolf Jansen, Patrick Kamieneski, Anton Koekemoer, Reagen Leimbach, Madeline Marshall, Rafael Ortiz III, Nor Pirzkal, Massimo Ricotti, Aaron Robotham, Michael Rutkowski, Russell Ryan, Payaswini Saikia, Jake Summers, Christopher Willmer, Haojing Yan. 2025-10-09. The Distribution of Quenched Galaxies in the Massive z = 0.87 Galaxy Cluster El Gordo. https://arxiv.org/abs/2510.08801

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