Precision kinematic Sunyaev-Zel’dovich measurements across halo mass and redshift with DESI DR2 and ACT DR6. II. Bright galaxy survey and emission-line galaxies
Year: 2026
Type: article
Abstract: We present the first high-significance spectroscopic stacked kinetic Sunyaev-Zel’dovich (kSZ) measurements of circumgalactic gas profiles for both bright galaxy survey (BGS) and emission line galaxy (ELG) tracers, combining DESI Data Release 2 with ACT Data Release 6. Using reconstructed line-of-sight velocities from the DESI galaxies and high-resolution ACT temperature maps, we detect the kSZ signal at high significance, reaching signal-to-noise ratios of up to ∼ 9 for BGS and ∼ 7.5 for ELGs in optimal stellar-mass selections. Together with the Luminous red galaxies (LRGs) measurements presented in Paper I, these constitute the most significant kSZ detections from any spectroscopic survey to date. We perform the analysis in both real and harmonic space, obtaining consistent results. By splitting both tracers into stellar-mass bins, we study the scaling of the kSZ amplitude with galaxy properties. Combining the kSZ measurements with ACT Data Release 6 (DR6) cosmic microwave background lensing maps enables a joint calibration of the galaxy-halo connection and the gas fractions of host halos. For the BGS galaxies, we observe low gas fractions around the virial radius relative to standard expectations, likely attributable to active galactic nuclei (AGN) activity. We find some evidence for higher-mass halos retaining a larger fraction of their baryons, consistent with more efficient feedback in lower-mass systems. For the ELG sample, dominated by blue, star-forming galaxies, we provide the first detection of the gas distribution in ELG host halos. The ELGs appear to exhibit relatively high gas fractions, which points to the possibility of weaker feedback (due to, e.g., low AGN and supernova feedback activity) at their mass scale. Finally, we present generalized Navarro-Frenk-White fits to the harmonic-space measurements, providing a compact parametrization of gas profiles for forward modeling in large-scale structure analyses.
DOI: 10.1103/g381-bz2j
Authors: B. Hadzhiyska, S. Ferraro, F. J. Qu, B. Ried Guachalla, E. Schaan, J. Aguilar, S. Ahlen, D. Bianchi, D. Brooks, F. J. Castander, E. Chaussidon, T. Claybaugh, A. de la Macorra, Arjun Dey, Biprateep Dey, P. Doel, J. E. Forero-Romero, E. Gaztañaga, Satya Gontcho A. Gontcho, G. Gutierrez, J. Guy, K. Honscheid, C. Howlett, D. Huterer, M. Ishak, R. Joyce, R. Kehoe, T. Kisner, A. Kremin, O. Lahav, M. Landriau, L. Le Guillou, A. Leauthaud, M. Manera, P. Martini, A. Meisner, R. Miquel, S. Nadathur, N. Palanque-Delabrouille, W. J. Percival, F. Prada, I. Pérez-Ràfols, G. Rossi, L. Samushia, E. Sanchez, E. F. Schlafly, D. Schlegel, J. Silber, D. Sprayberry, G. Tarlé, B. A. Weaver, R. Zhou, H. Zou
Institutions: University of Cambridge, Lawrence Berkeley National Laboratory, University of California, Berkeley, SLAC National Accelerator Laboratory, Stanford University, Boston University, University of Milan, Brera Astronomical Observatory, National Institute for Astrophysics, University College London, Institut d'Estudis Espacials de Catalunya, NSF NOIRLab, University of Pittsburgh, University of Toronto, Universidad de Los Andes, University of Portsmouth, University of Virginia, Fermi National Accelerator Laboratory, The Ohio State University, The University of Queensland, University of Michigan, The University of Texas at Dallas, Southern Methodist University, Sorbonne Université, University of California, Santa Cruz, Universitat Autònoma de Barcelona, Barcelona Institute of Science and Technology, Institució Catalana de Recerca i Estudis Avançats, Institut de Recherche sur les Lois Fondamentales de l'Univers, University of Waterloo, Perimeter Institute, Consejo Superior de Investigaciones Científicas, Instituto de Astrofísica de Andalucía, Universitat Politècnica de Catalunya, Sejong University, Ilia State University, Kansas State University, Evgeni Kharadze Georgian National Astrophysical Observatory, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas, Space Telescope Science Institute, Chinese Academy of Sciences
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Funders: National Science Foundation, U.S. Department of Energy, Gordon and Betty Moore Foundation, Office of the Director of National Intelligence, Heising-Simons Foundation, Ministerio de Ciencia, Innovación y Universidades, National Energy Research Scientific Computing Center, University of Cambridge, Consejo Nacional de Ciencia y Tecnología, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Office of Science, Science and Technology Facilities Council, Agencia Estatal de Investigación, Division of Astronomical Sciences, High Energy Physics, Lawrence Berkeley National Laboratory
OpenAlex ID: W7171861457