ODIN: Confirmation and 3D Reconstruction of Six Massive Protoclusters at Cosmic Noon
Abstract
Abstract Protoclusters represent sites of accelerated galaxy formation and extreme astrophysical activity characteristic of dense environments. Identifying massive protoclusters and mapping their spatial structures are therefore crucial for understanding how large-scale environment influences galaxy evolution. We combine wide-field Ly α imaging from the One-hundred-deg 2 DECam Imaging in Narrowbands survey with extensive Dark Energy Spectroscopic Instrument and ancillary spectroscopy across the extended COSMOS and XMM Large Scale Structure (LSS) fields (≈14 deg 2 ) to search for massive protoclusters. We confirm six systems at z ≈ 2.4 and ≈ 3.1, including three newly identified structures and three which overlap with previously known structures and/or systems detected using other tracers. We reconstruct their three-dimensional structures, estimate descendant halo masses, and for one structure at z ≈ 3.12, demonstrate that overlapping narrowband filters (NB497 and N501) provide accurate redshift tomography for emission-line galaxies. One protocluster at z ≈ 2.45 overlaps with one of the LATIS tomographic fields, enabling direct comparison between galaxy and H i overdensities traced by Ly α forest absorption. Another at z ≈ 3.12 hosts a massive quiescent galaxy ( M * ≈ 1.2 × 10 11 M ⊙ ), suggesting that overdense environments may play a role in accelerating galaxy assembly and quenching. Comparing Ly α emission properties across environments, we find that protocluster galaxies exhibit higher median line fluxes and a deficit of faint emitters relative to the field. The effect is strongest when combining 2D and 3D density information, indicating that galaxies in the densest protocluster cores are most affected by environmental processes. This effect is stronger at z ≈ 3.1 than at z ≈ 2.4, suggesting possible redshift evolution.
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Authors: Ashley Ortiz, Vandana Ramakrishnan, Kyoung-Soo Lee, Arjun Dey, Yucheng Guo, Ethan Pinarski, Anand Raichoor, Francisco Valdes, J. Aguilar, Steven Ahlen, M. Celeste Artale, Davide Bianchi, August Bliese, David Brooks, Rebecca Canning, Maria Cerdosino, Todd Claybaugh, Andrei Cuceu, Axel de la Macorra, Peter Doel, Jaime Forero, Eric Gawiser, Enrique Gaztanaga, Satya Gontcho, C. Gronwall, Lucia Guaita, Gaston Gutierrez, Hiram K. Herrera-Alcantar, Ho Seong Hwang, Woong-Seob Jeong, Dick Joyce, Robert Kehoe, Theodore Kisner, Anthony Kremin, Ankit Kumar, Ofer Lahav, Martin Landriau, Jaehyun Lee, Seong-Kook Lee, Laurent Le Guillou, Marc Manera, Aaron M. Meisner, Ramon Miquel, Byeongha Moon, John Moustakas, Adam Myers, Seshadri Nadathur, Nathalie Palanque-Delabrouille, Changbom Park, Will Percival, Ignasi Perez-Rafols, Francisco Prada, Eshwar Puvvada, Graziano Rossi, Eusebio Sanchez, David Schlegel, Michael Schubnell, Joseph Harry Silber, Hyunmi Song, David Sprayberry, Gregory Tarle, Paulina Troncoso, Ana Sofia Uzsoy, Benjamin Weaver, Yujin Yang, Rongpu Zhou, Hu Zou Hu Zou
Institutions: Universidad Nacional Autónoma de México, Chinese Academy of Sciences, University of Virginia, University of Michigan, University College London, Universitat Autònoma de Barcelona, Sorbonne Université, Chungnam National University, University of Waterloo, Institució Catalana de Recerca i Estudis Avançats, Arizona State University, Rutgers, The State University of New Jersey, Universidad Nacional de Córdoba, University of Wyoming, Wyoming Department of Education, Universitat Politècnica de Catalunya, Seoul National University, Purdue University West Lafayette, Université Paris-Saclay, University of Milan, Pennsylvania State University, University of Portsmouth, Sejong University, Lawrence Berkeley National Laboratory, Fermi National Accelerator Laboratory, University of Siena, Institut d'Estudis Espacials de Catalunya, Southern Methodist University, Institut d'Astrophysique de Paris, Instituto de Astrofísica de Andalucía, Institute of Space Science - INFLPR Subsidiary, Institute of Space Sciences, Universidad de Los Andes, Korea Institute for Advanced Study, Center for Astrophysics Harvard & Smithsonian, Universidad Andrés Bello, Brera Astronomical Observatory, Instituto de Astronomía Teórica y Experimental, Galaxies, Etoiles, Physique et Instrumentation, Millennium Engineering and Integration (United States), Korea Astronomy and Space Science Institute, Laboratoire Médiations, Institute for High Energy Physics, Perimeter Institute, Universidad Central de Chile