Superclustering with the Atacama Cosmology Telescope and Dark Energy Survey. II. Anisotropic Large-scale Coherence in Hot Gas, Galaxies, and Dark Matter

Lokken, M. and van Engelen, A. and Aguena, M. and Allam, S. S. and Anbajagane, D. and Bacon, D. and Baxter, E. and Blazek, J. and Bocquet, S. and Bond, J. R. and Brooks, D. and Calabrese, E. and Carnero Rosell, A. and Carretero, J. and Costanzi, M. and da Costa, L. N. and Coulton, W. R. and De Vicente, J. and Desai, S. and Doel, P. and Doux, C. and Duivenvoorden, A. J. and Dunkley, J. and Huang, Z. and Everett, S. and Ferrero, I. and Frieman, J. and García-Bellido, J. and Gatti, M. and Gaztanaga, E. and Giannini, G. and Gluscevic, Vera and Gruen, D. and Gruendl, R. A. and Guan, Y. and Gutierrez, G. and Hinton, S. R. and Hlozek, R. and Hollowood, D. L. and Honscheid, K. and James, D. J. and Kuehn, K. and Lahav, O. and Lee, S. and Li, Z. and Madhavacheril, M. and Marques, G. A. and Marshall, J. L. and Mena-Fernández, J. and Menanteau, F. and Miquel, R. and Myles, J. and Niemack, M. D. and Pandey, S. and Pereira, M. E. S. and Pieres, A. and Plazas Malagón, A. A. and Porredon, A. and Rodríguez-Monroy, M. and Roodman, A. and Samuroff, S. and Sanchez, E. and Sanchez Cid, D. and Santiago, B. and Schubnell, M. and Sevilla-Noarbe, I. and Sifón, C. and Smith, M. and Staggs, S. T. and Suchyta, E. and Swanson, M. E. C. and Tarle, G. and To, C-H. and Weaverdyck, N. and Wiseman, P. and Wollack, E. J. (2025) Superclustering with the Atacama Cosmology Telescope and Dark Energy Survey. II. Anisotropic Large-scale Coherence in Hot Gas, Galaxies, and Dark Matter. The Astrophysical Journal, 982 (2): 186. ISSN 0004-637X

Abstract

Statistics that capture the directional dependence of the baryon distribution in the cosmic web enable unique tests of cosmology and astrophysical feedback. We use constrained oriented stacking of thermal Sunyaev–Zel’dovich (tSZ) maps to measure the anisotropic distribution of hot gas 2.5–40 Mpc away from galaxy clusters embedded in massive filaments and superclusters. The cluster selection and orientation (at a scale of ∼15 Mpc) use Dark Energy Survey (DES) Year 3 data, while expanded tSZ maps from the Atacama Cosmology Telescope Data Release 6 enable a ∼3× more significant measurement of the extended gas compared to the technique’s proof-of-concept. Decomposing stacks into cosine multipoles of order m, we detect a dipole (m = 1) and quadrupole (m = 2) at 8σ–10σ, as well as evidence for m = 4 signal at up to 6σ, indicating sensitivity to late-time non-Gaussianity. We compare to Cardinal simulations with spherical gas models pasted onto dark matter halos. The fiducial tSZ data can discriminate between two models that deplete pressure differently in low-mass halos (mimicking astrophysical feedback), preferring higher average pressure in extended structures. However, uncertainty in the amount of cosmic infrared background contamination reduces the constraining power. Additionally, we apply the technique to DES galaxy density and weak lensing to study for the first time their oriented relationships with tSZ. In the tSZ-to-lensing relation, averaged on 7.5 Mpc (transverse) scales, we observe dependence on redshift but not shape or radial distance. Thus, on large scales, the superclustering of gas pressure, galaxies, and total matter is coherent in shape and extent.