论文标题
星系选择对星系簇的飞溅边界的影响
The impact of galaxy selection on the splashback boundaries of galaxy clusters
论文作者
论文摘要
我们探讨了使用Subhalo群体的数量密度测量的Galaxy簇的飞溅半径（$ r _ {\ rm sp} $）如何使用Illarteristng宇宙学银河形成模拟根据各种选择标准进行了更改。我们通过在0.5个DEX宽大块中堆叠的簇中提取最陡的径向梯度来识别$ r _ {\ rm sp} $，而我们的簇具有halo masses $ 10^{13} \ leq m _ {\ leq m _ {\ rm 200，mean} / mean} / mean} / prie} / prie} / {\ rm m} $ n \ oot {我们在Subhalo质量，星系恒星质量，$ i $ band绝对幅度和特定的恒星形成率中进行切割。我们发现，通常，质量和发光度增加的星系相对于固有的暗物质半径，测量的飞溅半径较小。我们还表明，可以使用淬火星系可靠地重建暗物质飞溅半径。这种趋势可能是由于银河系种群的变化所致。此外，我们能够协调不同的观察性预测，即基于星系数计数的$ r _ {\ rm sp} $，而暗物质可以通过这些研究所采用的选择功能来对齐或显示出显着的偏移（例如那些使用光学或SZ选择的簇）。最后，我们证明，通过数字计数测量的$ r _ {\ rm sp} $的变化不是由于群集内外的星系丰度的简单变化。
We explore how the splashback radius ($R_{\rm sp}$) of galaxy clusters, measured using the number density of the subhalo population, changes based on various selection criteria using the IllustrisTNG cosmological galaxy formation simulation. We identify $R_{\rm sp}$ by extracting the steepest radial gradient in a stacked set of clusters in 0.5 dex wide mass bins, with our clusters having halo masses $10^{13} \leq M_{\rm 200, mean} / {\rm M}_\odot \leq 10^{15}$. We apply cuts in subhalo mass, galaxy stellar mass, $i$-band absolute magnitude and specific star formation rate. We find that, generally, galaxies of increasing mass and luminosity trace smaller measured splashback radii relative to the intrinsic dark matter radius. We also show that quenched galaxies may be used to reliably reconstruct the dark matter splashback radius. This trend is likely due to changes in the galaxy population. Additionally, we are able to reconcile different observational predictions that $R_{\rm sp}$ based upon galaxy number counts and dark matter may either align or show significant offset (e.g. those using optically- or SZ-selected clusters) through the selection functions that these studies employ. Finally, we demonstrate that changes in $R_{\rm sp}$ measured through number counts are not due to a simple change in galaxy abundance inside and outside of the cluster.
