We probe the self-interactions of dark matter using observational data of relaxed galaxy groups and clusters. Our analysis uses the Jeans formalism and considers a wider range of systematic effects than in previous work, including adiabatic contraction and stellar anisotropy, to robustly constrain the self-interaction cross section. For both groups and clusters, our results show a mild preference for a nonzero cross section compared with cold collisionless dark matter. Our groups result, $\sigma/m=0.5\pm0.2~\mathrm{cm}^2/\mathrm{g}$, places the first constraint on self-interacting dark matter (SIDM) at an intermediate scale between galaxies and massive clusters. Our clusters result is $\sigma/m=0.19\pm0.09~\mathrm{cm}^2/\mathrm{g}$, with an upper limit of $\sigma / m < 0.35~\mathrm{cm}^2/\mathrm{g}$ (95% CL). Thus, our results disfavor a velocity-independent cross section of order $1~\mathrm{cm}^2/\mathrm{g}$ or larger needed to address small scale structure problems in galaxies, but are consistent with a velocity-dependent cross section that decreases with increasing scattering velocity. Comparing the cross sections with and without the effect of adiabatic contraction, we find that adiabatic contraction produces slightly larger values for our data sample, but they are consistent at the $1\sigma$ level. Finally, to validate our approach, we apply our Jeans analysis to a sample of mock data generated from SIDM-plus-baryons simulations with $\sigma/m = 1~\mathrm{cm}^2/\mathrm{g}$. This is the first test of the Jeans model at the level of stellar and lensing observables directly measured from simulations. We find our analysis gives a robust determination of the cross section, as well as consistently inferring the true baryon and dark matter density profiles.

中文翻译：

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来自星系群和星系团的速度相关的自相互作用暗物质

我们使用松弛星系群和星团的观测数据探索暗物质的自相互作用。我们的分析使用 Jeans 形式主义，并考虑了比以前工作更广泛的系统效应，包括绝热收缩和恒星各向异性，以稳健地约束自相互作用横截面。对于组和星团，我们的结果显示，与冷无碰撞暗物质相比，对非零截面的偏爱温和。我们小组的结果 $\sigma/m=0.5\pm0.2~\mathrm{cm}^2/\mathrm{g}$，在星系之间的中间尺度上对自相互作用暗物质 (SIDM) 施加了第一个约束和庞大的集群。我们的聚类结果是 $\sigma/m=0.19\pm0.09~\mathrm{cm}^2/\mathrm{g}$，上限为 $\sigma / m < 0.35~\mathrm{cm}^ 2/\mathrm{g}$ (95% CL)。因此，我们的结果不赞成解决星系中小尺度结构问题所需的 $1~\mathrm{cm}^2/\mathrm{g}$ 或更大的速度无关截面，但与速度相关截面一致随散射速度的增加而减小。比较有和没有绝热收缩影响的横截面，我们发现绝热收缩为我们的数据样本产生了稍大的值，但它们在 $1\sigma$ 水平上是一致的。最后，为了验证我们的方法，我们将我们的 Jeans 分析应用于从 SIDM 加重子模拟生成的模拟数据样本，其中 $\sigma/m = 1~\mathrm{cm}^2/\mathrm{g}$。这是在直接从模拟中测量的恒星和透镜观测水平上对 Jeans 模型进行的第一次测试。