Title: CGM$^2$ $+$ CASBaH: The Mass Dependence of H~I Ly$α$-Galaxy Clustering and the Extent of the CGM Show Chinese title

Title: CGM$^2$ $+$ CASBaH：H~I Ly$α$-星系团聚的质量依赖性及CGM的范围

Abstract: We combine datasets from the CGM$^{2}$ and CASBaH surveys to model a transition point, $R_{\rm cross}$, between circumgalactic and intergalactic media (CGM and IGM, respectively). In total, our data consist of 7244 galaxies at z < 0.5 with precisely measured spectroscopic redshifts, all having impact parameters of 0.01 - 20 comoving Mpc from 28 QSO sightlines with high-resolution UV spectra that cover H I Ly$\alpha$. Our best-fitting model is an exclusionary two-component model that combines a 3D absorber-galaxy cross correlation function with a simple Gaussian profile at inner radii to represent the CGM. By design, this model gives rise to a determination of $R_{\rm cross}$ as a function of galaxy stellar mass, which can be interpreted as the boundary between the CGM and IGM. For galaxies with $10^8 \leq M_{\star}/M_{\odot} \leq 10^{10.5}$, we find that $R_{\rm cross}(M_{\star}) \approx 2 \pm 0.6 R_{\rm vir}$. Additionally, we find excellent agreement between $R_{\rm cross}(M_{\star})$ and the theoretically-determined splashback radius for galaxies in this mass range. Overall, our results favor models of galaxy evolution at z < 0.5 that distribute $T \approx 10^{4}$K gas to distances beyond the virial radius. Show Chinese abstract

Abstract: 我们将CGM$^{2}$和CASBaH调查的数据集结合起来，对星系晕际介质（CGM）和星际介质（IGM）之间的过渡点$R_{\rm cross}$进行建模。 总计，我们的数据包括7244个红移z < 0.5的星系，这些星系具有精确测量的光谱红移，所有星系与28条类星体视线的距离均为0.01 - 20共动Mpc，这些类星体视线具有覆盖H I Ly$\alpha$的高分辨率紫外光谱。 我们最佳拟合的模型是一个排他性双组分模型，它结合了三维吸收体-星系交叉相关函数和内半径处的简单高斯分布，以表示CGM。 按照设计，该模型能够确定$R_{\rm cross}$随星系恒星质量的变化，这可以被解释为CGM和IGM之间的边界。 对于具有$10^8 \leq M_{\star}/M_{\odot} \leq 10^{10.5}$的星系，我们发现$R_{\rm cross}(M_{\star}) \approx 2 \pm 0.6 R_{\rm vir}$。 此外，我们发现$R_{\rm cross}(M_{\star})$与这一质量范围内的星系理论上确定的溅落半径之间有很好的一致性。 总体而言，我们的结果支持红移小于0.5的星系演化模型，这些模型将$T \approx 10^{4}$K气体分布到晕半径以外的距离。