Estimating the dark matter velocity anisotropy to the cluster edge
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Estimating the dark matter velocity anisotropy to the cluster edge. / Svensmark, Jacob; Hansen, Steen H.; Martizzi, Davide; Moore, Ben; Teyssier, Romain.
In: Monthly Notices of the Royal Astronomical Society, Vol. 500, 23.10.2020, p. 3151-3161.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Estimating the dark matter velocity anisotropy to the cluster edge
AU - Svensmark, Jacob
AU - Hansen, Steen H.
AU - Martizzi, Davide
AU - Moore, Ben
AU - Teyssier, Romain
N1 - 20 pages, 10 figures
PY - 2020/10/23
Y1 - 2020/10/23
N2 - Dark matter (DM) dominates the properties of large cosmological structures such as galaxy clusters, and the mass profiles of the DM have been inferred for these equilibrated structures for years by using cluster X-ray surface brightnesses and temperatures. A new method has been proposed, which should allow us to infer a dynamical property of the DM, namely the velocity anisotropy. For the gas, a similar velocity anisotropy is zero due to frequent collisions; however, the collisionless nature of DM allows it to be non-trivial. Numerical simulations have for years found non-zero and radially varying DM velocity anisotropies. Here we employ the method proposed by Hansen & Piffaretti, and developed by Høst et al. to infer the DM velocity anisotropy in the bright galaxy cluster Perseus, to near five times the radii previously obtained. We find the DM velocity anisotropy to be consistent with the results of numerical simulations, however, still with large error bars. At half the virial radius, we find the DM velocity anisotropy to be non-zero at 1.7σ, lending support to the collisionless nature of DM.
AB - Dark matter (DM) dominates the properties of large cosmological structures such as galaxy clusters, and the mass profiles of the DM have been inferred for these equilibrated structures for years by using cluster X-ray surface brightnesses and temperatures. A new method has been proposed, which should allow us to infer a dynamical property of the DM, namely the velocity anisotropy. For the gas, a similar velocity anisotropy is zero due to frequent collisions; however, the collisionless nature of DM allows it to be non-trivial. Numerical simulations have for years found non-zero and radially varying DM velocity anisotropies. Here we employ the method proposed by Hansen & Piffaretti, and developed by Høst et al. to infer the DM velocity anisotropy in the bright galaxy cluster Perseus, to near five times the radii previously obtained. We find the DM velocity anisotropy to be consistent with the results of numerical simulations, however, still with large error bars. At half the virial radius, we find the DM velocity anisotropy to be non-zero at 1.7σ, lending support to the collisionless nature of DM.
KW - astro-ph.CO
KW - 85A04
U2 - 10.1093/mnras/staa3279
DO - 10.1093/mnras/staa3279
M3 - Journal article
VL - 500
SP - 3151
EP - 3161
JO - Royal Astronomical Society. Monthly Notices
JF - Royal Astronomical Society. Monthly Notices
SN - 0035-8711
ER -
ID: 229808078