Thakore, B. and Negro, M. and Regis, M. and Camera, S. and Gruen, D. and Fornengo, N. and Roodman, A. and Porredon, A. and Schutt, T. and Cuoco, A. and Alarcon, A. and Amon, A. and Bechtol, K. and Becker, M.R. and Bernstein, G.M. and Campos, A. and Carnero Rosell, A. and Carrasco Kind, M. and Cawthon, R. and Chang, C. and Chen, R. and Choi, A. and Cordero, J. and Davis, C. and DeRose, J. and Diehl, H.T. and Dodelson, S. and Doux, C. and Drlica-Wagner, A. and Eckert, K. and Elvin-Poole, J. and Everett, S. and Ferté, A. and Gatti, M. and Giannini, G. and Gruendl, R.A. and Harrison, I. and Hartley, W.G. and Huff, E.M. and Jarvis, M. and Kuropatkin, N. and Leget, P.-F. and MacCrann, N. and McCullough, J. and Myles, J. and Navarro-Alsina, A. and Pandey, S. and Prat, J. and Raveri, M. and Rollins, R.P. and Ross, A.J. and Rykoff, E.S. and Sánchez, C. and Secco, L.F. and Sevilla-Noarbe, I. and Sheldon, E. and Shin, T. and Troxel, M.A. and Tutusaus, I. and Yanny, B. and Yin, B. and Zhang, Y. and Aguena, M. and Brooks, D. and Carretero, J. and da Costa, L.N. and Davis, T.M. and De Vicente, J. and Desai, S. and Doel, P. and Flaugher, B. and Frieman, J. and García-Bellido, J. and Gaztanaga, E. and Gutierrez, G. and Hinton, S.R. and Hollowood, D.L. and Honscheid, K. and James, D.J. and Kuehn, K. and Lahav, O. and Lee, S. and Lima, M. and Marshall, J.L. and Mena-Fernández, J. and Miquel, R. and Ogando, R.L.C. and Palmese, A. and Pieres, A. and Plazas Malagón, A.A. and Samuroff, S. and Sanchez, E. and Sanchez Cid, D. and Smith, M. and Suchyta, E. and Tarle, G. and Vikram, V. and Walker, A.R. and Weaverdyck, N. (2025) High-significance detection of correlation between the unresolved gamma-ray background and the large-scale cosmic structure. Journal of Cosmology and Astroparticle Physics, 2025 (06): 037. ISSN 1475-7516
Full text not available from this repository.Abstract
Our understanding of the γ-ray sky has improved dramatically in the past decade, however, the unresolved γ-ray background (UGRB) still has a potential wealth of information about the faintest γ-ray sources pervading the Universe. Statistical cross-correlations with tracers of cosmic structure can indirectly identify the populations that most characterize the γ-ray background. In this study, we analyze the angular correlation between the γ-ray background and the matter distribution in the Universe as traced by gravitational lensing, leveraging more than a decade of observations from the Fermi-Large Area Telescope (LAT) and 3 years of data from the Dark Energy Survey (DES). We detect a correlation at signal-to-noise ratio of 8.9. Most of the statistical significance comes from large scales, demonstrating, for the first time, that a substantial portion of the UGRB aligns with the mass clustering of the Universe as traced by weak lensing. Blazars provide a plausible explanation for this signal, especially if those contributing to the correlation reside in halos of large mass (∼ 1014 M ⊙) and account for approximately 30–40% of the UGRB above 10 GeV. Additionally, we observe a preference for a curved γ-ray energy spectrum, with a log-parabolic shape being favored over a power-law. We also discuss the possibility of modifications to the blazar model and the inclusion of additional γ-ray sources, such as star-forming galaxies, misalinged active galactic nuclei, or particle dark matter.