标题： 自相互作用暗物质在松散星系团中的约束 显示英文标题

标题： Constraints on Self-Interacting dark matter from relaxed galaxy groups

摘要： 自相互作用暗物质（SIDM）被提出作为标准无碰撞冷暗物质的替代方案，以解释小尺度上观测到的星系旋转曲线多样性和核心-尖核问题。 在这里，我们估计了11个平衡星系团的SIDM约束，这些星系团的X射线观测数据来自钱德拉和XMM-牛顿。 我们将暗物质密度分布拟合到Einasto轮廓，并使用估计的Einasto$\alpha$参数来约束SIDM的截面，这是基于Eckert等人（2022）获得的两者之间的经验关系。 我们得到七个星系的截面每单位质量（$\sigma/m$）的非零中心估计值，其中最精确的估计是针对NGC 5044，给出的值为$\sigma/m=0.165 \pm 0.025~\rm{cm^2/g}$，对于约300公里/秒的暗物质速度弥散。 对于其余四个星系，我们得到了95%置信度的上限对$\sigma/m < 0.16-6.61~\rm{cm^2/g}$，暗物质速度弥散在200-500公里/秒之间，我们样本中最严格的限制是针对MKW 4星系，给出的值为$\sigma/m< 0.16~\rm{cm^2/g}$，对于约350公里/秒的暗物质速度弥散。 显示英文摘要

摘要： Self-interacting dark matter (SIDM) has been proposed as an alternative to the standard collisionless cold dark matter to explain the diversity of galactic rotation curves and core-cusp problems seen at small scales. Here, we estimate the constraints on SIDM for a sample of 11 relaxed galaxy groups with X-ray observations from Chandra and XMM-Newton. We fit the dark matter density distribution to the Einasto profile and use the estimated Einasto $\alpha$ parameter to constrain the SIDM cross-section, based on the empirical relation between the two, which was obtained in Eckert et al (2022). We obtain a non-zero central estimate for the cross-section per unit mass ($\sigma/m$) for seven groups, with the most precise estimate obtained for NGC 5044, given by $\sigma/m=0.165 \pm 0.025~\rm{cm^2/g}$, for dark matter velocity dispersion of about 300 km/sec. For the remaining four groups, we obtain 95% c.l. upper limits on $\sigma/m < 0.16-6.61~\rm{cm^2/g}$ with dark matter velocity dispersions between 200-500 km/sec, with the most stringent limit for our sample obtained for the group MKW 4, given by $\sigma/m< 0.16~\rm{cm^2/g}$ for dark matter velocity dispersion of about 350 km/sec.