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arXiv 2602.15934astro-ph.GA
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CLASH-VLT速度各向异性剖面在大规模星系团堆叠中的研究

CLASH-VLT velocity anisotropy profiles in a stack of massive galaxy clusters

Università degli Studi di Milano（米兰大学）；Università di Salerno（萨莱诺大学）；Università degli Studi di Milano Bicocca（米兰比可卡大学）；University of Ferrara（费拉拉大学）

E. Maraboli, A. Biviano, C. Grillo, A. Mercurio, L. Pizzuti, P. Rosati, M. D'Addona

备注：
Accepted for publication by A&A, 20 pages, 12 figures
发表信息：
A&A 708, A264 (2026)
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AI总结：

通过分析九个大质量星系团的堆叠投影相空间，研究不同成员群体的速度各向异性剖面β(r)，发现各向异性从中心到virial半径逐渐增加，并在约250kpc处出现下降。

摘要：

通过分析九个大质量星系团的堆叠投影相空间，研究不同成员群体的速度各向异性剖面β(r)，发现各向异性从中心到virial半径逐渐增加，并在约250kpc处出现下降。

英文摘要：

We measure the velocity anisotropy profile $β(r)$ of different galaxy cluster member populations by analysing the stacked projected phase space of nine massive ($M_\mathrm{200c}>7\times10^{14}$ M$_\odot$) galaxy clusters at intermediate redshifts ($0.18 < z < 0.45$). We select our sample of galaxy clusters by choosing the most round and virialised objects among the targets of the CLASH-VLT spectroscopic program, which offers a large spectral database. Complementary MUSE observations on most of these clusters allowed us to identify an unprecedented number of cluster members, strongly enhancing the precision of our measurement with respect to previous studies. Our sample of cluster members is divided in four classes: red and blue by colour, and high- and low-mass by stellar mass. We employ two parallel techniques, namely the MAMPOSSt method (parametric in $β(r)$) and the Jeans equation inversion (non parametric in $β(r)$). The results from both techniques are found in agreement for any given cluster member population, and suggest that the orbital anisotropy in galaxy clusters grows from the centre (where $β\approx 0.2-0.4$) to the virial radius ($β\gtrsim 0.8$), and it is similar for the different cluster member populations. We also find an interesting dynamical feature in the Jeans inversion results, that is a drop in $β(r)$ at a distance of $\sim 250$ kpc from the cluster centre. We provide robust anisotropy estimates by exploring a highly significant number of model combinations: 72 with MAMPOSSt (varying the mass, surface number density, $β(r)$ model, and galaxy population) and 18 (varying total mass model and galaxy population) in the Jeans inversion. Such an extensive investigation of the $β(r)$ profile in galaxy clusters is a wide basis for future studies on cluster dynamical masses and cluster cosmology in the era of large spectroscopic surveys

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