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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
}
TY - JOUR
T1 - High-significance detection of correlation between the unresolved gamma-ray background and the large-scale cosmic structure
AU - Thakore, B.
AU - Negro, M.
AU - Regis, M.
AU - Camera, S.
AU - Gruen, D.
AU - Fornengo, N.
AU - Roodman, A.
AU - Porredon, A.
AU - Schutt, T.
AU - Cuoco, A.
AU - Alarcon, A.
AU - Amon, A.
AU - Bechtol, K.
AU - Becker, M.R.
AU - Bernstein, G.M.
AU - Campos, A.
AU - Carnero Rosell, A.
AU - Carrasco Kind, M.
AU - Cawthon, R.
AU - Chang, C.
AU - Chen, R.
AU - Choi, A.
AU - Cordero, J.
AU - Davis, C.
AU - DeRose, J.
AU - Diehl, H.T.
AU - Dodelson, S.
AU - Doux, C.
AU - Drlica-Wagner, A.
AU - Eckert, K.
AU - Elvin-Poole, J.
AU - Everett, S.
AU - Ferté, A.
AU - Gatti, M.
AU - Giannini, G.
AU - Gruendl, R.A.
AU - Harrison, I.
AU - Hartley, W.G.
AU - Huff, E.M.
AU - Jarvis, M.
AU - Kuropatkin, N.
AU - Leget, P.-F.
AU - MacCrann, N.
AU - McCullough, J.
AU - Myles, J.
AU - Navarro-Alsina, A.
AU - Pandey, S.
AU - Prat, J.
AU - Raveri, M.
AU - Rollins, R.P.
AU - Ross, A.J.
AU - Rykoff, E.S.
AU - Sánchez, C.
AU - Secco, L.F.
AU - Sevilla-Noarbe, I.
AU - Sheldon, E.
AU - Shin, T.
AU - Troxel, M.A.
AU - Tutusaus, I.
AU - Yanny, B.
AU - Yin, B.
AU - Zhang, Y.
AU - Aguena, M.
AU - Brooks, D.
AU - Carretero, J.
AU - da Costa, L.N.
AU - Davis, T.M.
AU - De Vicente, J.
AU - Desai, S.
AU - Doel, P.
AU - Flaugher, B.
AU - Frieman, J.
AU - García-Bellido, J.
AU - Gaztanaga, E.
AU - Gutierrez, G.
AU - Hinton, S.R.
AU - Hollowood, D.L.
AU - Honscheid, K.
AU - James, D.J.
AU - Kuehn, K.
AU - Lahav, O.
AU - Lee, S.
AU - Lima, M.
AU - Marshall, J.L.
AU - Mena-Fernández, J.
AU - Miquel, R.
AU - Ogando, R.L.C.
AU - Palmese, A.
AU - Pieres, A.
AU - Plazas Malagón, A.A.
AU - Samuroff, S.
AU - Sanchez, E.
AU - Sanchez Cid, D.
AU - Smith, M.
AU - Suchyta, E.
AU - Tarle, G.
AU - Vikram, V.
AU - Walker, A.R.
AU - Weaverdyck, N.
PY - 2025/6/19
Y1 - 2025/6/19
N2 - 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.
AB - 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.
KW - Bayesian reasoning
KW - weak gravitational lensing
KW - gamma ray experiments
KW - galaxy surveys
U2 - 10.1088/1475-7516/2025/06/037
DO - 10.1088/1475-7516/2025/06/037
M3 - Journal article
VL - 2025
JO - Journal of Cosmology and Astroparticle Physics
JF - Journal of Cosmology and Astroparticle Physics
SN - 1475-7516
IS - 06
M1 - 037
ER -