标题： 星系团内光的测光分析及TNG300模拟和大视场观测 显示英文标题

标题： Photometric analysis of the intracluster light in the TNG300 simulation and wide-field observations

摘要： 我们提出了一种稳健的、直接的比较，对比了TNG300磁流体动力学宇宙学模拟中星系团内光（ICL）的测光特性与Wendelstein宽视场成像仪（WWFI）观测结果的测光特性。 这是通过生成40个大质量（$\log\left(M_{\rm 200, crit}/{\rm M}_{\odot}\right) > 14.5$）TNG300星系团在$z \approx 0.06$波段的合成$g'$波段图像来实现的，这些图像紧密模仿WWFI观测结果，然后对合成图像和真实图像进行相同的测光计算。 重要的是，我们对两个数据集应用了相同的基于观测的卫星遮蔽程序，这有效地消除了由晕探测器引入的任何可能偏差。 我们首先分析了每个星系团的“平滑”恒星成分的光分布，该成分由最亮星系（BCG）加上ICL组成，并发现它在TNG300中比观测结果大约延伸两倍，同时亮度也大约高出1$g'$每平方角秒1$^{-2}$的星等。 我们随后通过考虑几种ICL定义来量化$f_{\rm ICL}$，即相对于BCG+ICL的ICL分数：(i) 比表面亮度截止值27$g'$等级弧秒$^{-2}$更暗的光，(ii) 超过de Vaucouleurs轮廓的多余光，(iii) 超过两倍半光半径（$2 r_{\rm half}$）的光，以及(iv) 超过固定圆形孔径30、50或100千秒差距的光。 对于大多数定义，模拟和观测之间的中位数$f_{\rm ICL}$一致。 然而，观测在$f_{\rm ICL}$上表现出更大的离散性，我们认为这主要是由于总BCG+ICL光度的观测不确定性，而不是真实宇宙中集群间的“真实”变化。 我们还发现大多数方法得出的中位数$f_{\rm ICL}$值接近 0.3，这与 BCG/ICL 转变半径大约在$2 r_{\rm half}$相一致。 显示英文摘要

摘要： We present a robust, apples-to-apples comparison between the photometric properties of the intracluster light (ICL) in the TNG300 magnetohydrodynamic cosmological simulation and those in Wendelstein Wide Field Imager (WWFI) observations. This is accomplished by generating synthetic $g'$-band images of 40 massive ($\log\left(M_{\rm 200, crit}/{\rm M}_{\odot}\right) > 14.5$) TNG300 clusters at $z \approx 0.06$, closely mimicking WWFI observations, and then performing identical photometric calculations on the synthetic and real images. Importantly, we apply the same observationally motivated satellite-masking procedure to both data-sets, which effectively removes any possible biases introduced by the halo finder. We first analyze the light distribution of the `smooth' stellar component of each cluster, composed of the brightest cluster galaxy (BCG) plus the ICL, and find that it tends to be about twice as extended in TNG300 than in observations, while also being approximately 1 $g'$ mag arcsec$^{-2}$ brighter. We then quantify $f_{\rm ICL}$, the ICL fraction relative to the BCG+ICL, by considering several ICL definitions: (i) the light dimmer than a surface brightness cut at 27 $g'$ mag arcsec$^{-2}$, (ii) the excess light over a de Vaucouleurs profile, (iii) the light beyond twice the half-light radius ($2 r_{\rm half}$), and (iv) the light beyond a fixed circular aperture of 30, 50, or 100 kpc. For most definitions, the median $f_{\rm ICL}$ is consistent between simulation and observations. However, the observations exhibit larger scatter in $f_{\rm ICL}$, which we attribute primarily to observational uncertainties in the total BCG+ICL luminosity rather than `true' cluster-to-cluster variation in the real Universe. We also find that most methods yield median $f_{\rm ICL}$ values near 0.3, which is consistent with a BCG/ICL transition radius around $2 r_{\rm half}$.