TY - JOUR
T1 - Prospects for γ-ray observations of the Perseus galaxy cluster with the Cherenkov Telescope Array
AU - the CTA Consortium
AU - Abe, K.
AU - Abe, S.
AU - Acero, F.
AU - Acharyya, A.
AU - Adam, R.
AU - Aguasca-Cabot, A.
AU - Agudo, I.
AU - Aguirre-Santaella, A.
AU - Alfaro, J.
AU - Alfaro, R.
AU - Alvarez-Crespo, N.
AU - Batista, R. Alves
AU - Amans, J. P.
AU - Amato, E.
AU - Angüner, E. O.
AU - Antonelli, L. A.
AU - Aramo, C.
AU - Araya, M.
AU - Arcaro, C.
AU - Arrabito, L.
AU - Asano, K.
AU - Ascasíbar, Y.
AU - Aschersleben, J.
AU - Ashkar, H.
AU - Stuani, L. Augusto
AU - Baack, D.
AU - Backes, M.
AU - Baktash, A.
AU - Balazs, C.
AU - Balbo, M.
AU - Ballester, O.
AU - Larriva, A. Baquero
AU - Martins, V. Barbosa
AU - de Almeida, U. Barres
AU - Barrio, J. A.
AU - Batista, P. I.
AU - Batkovic, I.
AU - Batzofin, R.
AU - Baxter, J.
AU - González, J. Becerra
AU - Beck, G.
AU - Tjus, J. Becker
AU - Benbow, W.
AU - Medrano, J. Bernete
AU - Bernlöhr, K.
AU - Berti, A.
AU - Bertucci, B.
AU - Chaty, S.
AU - Fegan, S.
AU - Horan, D.
N1 - Publisher Copyright:
© 2024 The Author(s).
PY - 2024/10/1
Y1 - 2024/10/1
N2 - Galaxy clusters are expected to be both dark matter (DM) reservoirs and storage rooms for the cosmic-ray protons (CRp) that accumulate along the cluster’s formation history. Accordingly, they are excellent targets to search for signals of DM annihilation and decay at γ-ray energies and are predicted to be sources of large-scale γ-ray emission due to hadronic interactions in the intracluster medium (ICM). In this paper, we estimate the sensitivity of the Cherenkov Telescope Array (CTA) to detect diffuse γ-ray emission from the Perseus galaxy cluster. We first perform a detailed spatial and spectral modelling of the expected signal for both the DM and the CRp components. For each case, we compute the expected CTA sensitivity accounting for the CTA instrument response functions. The CTA observing strategy of the Perseus cluster is also discussed. In the absence of a diffuse signal (non-detection), CTA should constrain the CRp to thermal energy ratio X500 within the characteristic radius R500 down to about X500 < 3 × 10−3, for a spatial CRp distribution that follows the thermal gas and a CRp spectral index αCRp = 2.3. Under the optimistic assumption of a pure hadronic origin of the Perseus radio mini-halo and depending on the assumed magnetic field profile, CTA should measure αCRp down to about ∆αCRp ≃ 0.1 and the CRp spatial distribution with 10% precision, respectively. Regarding DM, CTA should improve the current ground-based γ-ray DM limits from clusters observations on the velocity-averaged annihilation cross-section by a factor of up to ∼ 5, depending on the modelling of DM halo substructure. In the case of decay of DM particles, CTA will explore a new region of the parameter space, reaching models with τχ > 1027 s for DM masses above 1 TeV. These constraints will provide unprecedented sensitivity to the physics of both CRp acceleration and transport at cluster scale and to TeV DM particle models, especially in the decay scenario.
AB - Galaxy clusters are expected to be both dark matter (DM) reservoirs and storage rooms for the cosmic-ray protons (CRp) that accumulate along the cluster’s formation history. Accordingly, they are excellent targets to search for signals of DM annihilation and decay at γ-ray energies and are predicted to be sources of large-scale γ-ray emission due to hadronic interactions in the intracluster medium (ICM). In this paper, we estimate the sensitivity of the Cherenkov Telescope Array (CTA) to detect diffuse γ-ray emission from the Perseus galaxy cluster. We first perform a detailed spatial and spectral modelling of the expected signal for both the DM and the CRp components. For each case, we compute the expected CTA sensitivity accounting for the CTA instrument response functions. The CTA observing strategy of the Perseus cluster is also discussed. In the absence of a diffuse signal (non-detection), CTA should constrain the CRp to thermal energy ratio X500 within the characteristic radius R500 down to about X500 < 3 × 10−3, for a spatial CRp distribution that follows the thermal gas and a CRp spectral index αCRp = 2.3. Under the optimistic assumption of a pure hadronic origin of the Perseus radio mini-halo and depending on the assumed magnetic field profile, CTA should measure αCRp down to about ∆αCRp ≃ 0.1 and the CRp spatial distribution with 10% precision, respectively. Regarding DM, CTA should improve the current ground-based γ-ray DM limits from clusters observations on the velocity-averaged annihilation cross-section by a factor of up to ∼ 5, depending on the modelling of DM halo substructure. In the case of decay of DM particles, CTA will explore a new region of the parameter space, reaching models with τχ > 1027 s for DM masses above 1 TeV. These constraints will provide unprecedented sensitivity to the physics of both CRp acceleration and transport at cluster scale and to TeV DM particle models, especially in the decay scenario.
KW - cosmic ray experiments
KW - dark matter experiments
KW - galaxy clusters
KW - gamma ray experiments
U2 - 10.1088/1475-7516/2024/10/004
DO - 10.1088/1475-7516/2024/10/004
M3 - Article
AN - SCOPUS:85209538799
SN - 1475-7516
VL - 2024
JO - Journal of Cosmology and Astroparticle Physics
JF - Journal of Cosmology and Astroparticle Physics
IS - 10
M1 - 004
ER -