论文标题
通过星系簇中的径向加速关系测试暗物质的无碰撞性质
Testing the Collisionless Nature of Dark Matter with the Radial Acceleration Relation in Galaxy Clusters
论文作者
论文摘要
径向加速关系（RAR）代表了推断的总和和BARYONIC CENTRIPETAL加速度之间的紧密经验关系，$ g _ {\ rm {tot}} = gm _ {\ rm _ {\ rm {tot}}}}} $ g _ {\ rm {bar}} = gm _ {\ rm {bar}}（<r）/r^2 $，在星系和星系簇中观察到。这两个数量之间的紧密相关性可以洞悉暗物质的性质。在这里，我们使用巴哈马（宇宙学流体动力学模拟的最先进的套件）来表征群集尺度的光环中的RAR，用于冷和无碰撞的暗物质（CDM）和自我互动的暗物质（SIDM）模型。 SIDM光晕通常降低了中央暗物质密度，与CDM相比，中央区域的总加速度降低。我们比较了模拟不同暗物质模型的星系簇中的RAR和从冲突观测中推断出的RAR。我们的比较表明，CDM模型中的集群尺度RAR与Tian等人获得的冲突RAR提供了极好的匹配。包括由最亮星系星（BCG）探测的高加速度制度。相比之下，SIDM横截面较大的模型产生越来越差的冲突RAR匹配。不包括BCG区域会导致对SIDM横截面的较弱但仍有竞争性的限制。使用中央$ r <100 $ kpc区域之外的RAR数据，具有$σ/m = 0.3 $ cm $^{2} $ g $^{ - 1} $的SIDM型号以相对于CDM模型的$3.8σ$级别不利。这项研究证明了簇尺度rar在测试暗物质的无碰撞性质方面的力量。
The radial acceleration relation (RAR) represents a tight empirical relation between the inferred total and baryonic centripetal accelerations, $g_{\rm{tot}}=GM_{\rm{tot}}(<r)/r^2$ and $g_{\rm{bar}}=GM_{\rm{bar}}(<r)/r^2$, observed in galaxies and galaxy clusters. The tight correlation between these two quantities can provide insight into the nature of dark matter. Here we use BAHAMAS, a state-of-the-art suite of cosmological hydrodynamical simulations, to characterize the RAR in cluster-scale halos for both cold and collisionless dark matter (CDM) and self-interacting dark matter (SIDM) models. SIDM halos generally have reduced central dark matter densities, which reduces the total acceleration in the central region when compared with CDM. We compare the RARs in galaxy clusters simulated with different dark matter models to the RAR inferred from CLASH observations. Our comparison shows that the cluster-scale RAR in the CDM model provides an excellent match to the CLASH RAR obtained by Tian et al. including the high-acceleration regime probed by the brightest cluster galaxies (BCGs). By contrast, models with a larger SIDM cross-section yield increasingly poorer matches to the CLASH RAR. Excluding the BCG regions results in a weaker but still competitive constraint on the SIDM cross-section. Using the RAR data outside the central $r<100$kpc region, an SIDM model with $σ/m=0.3$cm$^{2}$g$^{-1}$ is disfavored at the $3.8σ$ level with respect to the CDM model. This study demonstrates the power of the cluster-scale RAR for testing the collisionless nature of dark matter.
