How to interpret measurements of diffuse light in stacked observations of groups and clusters of galaxies
How to interpret measurements of diffuse light in stacked observations of groups and clusters of galaxies
复制标题
如何解释星系群和星系团的堆叠观测中漫射光的测量结果
DOI：
10.1093/mnras/stac3357
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发表时间：
2023
影响因子：
4.8
通讯作者：
Ahad S
中科院分区：
文献类型：
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作者：
Ahad S
星系群和星系团内的漫射光为了解大规模宇宙结构的生长提供了宝贵的见解。在这种情况下，星系团特别有趣，因为它们代表了星系晕和巨大星团之间的联系。然而，低表面亮度使得它们的漫射光很难单独检测。堆叠许多组是一种有前途的替代方案，但其物理解释由于漫射光轮廓与其他组属性可能的系统变化而变得复杂。另一个问题是团体中心的选择常常含糊不清。我们通过绣球花宇宙流体动力学模拟对 497 个星系团和星团进行模拟观测，探索这些挑战，这些星系团和星团的晕质量从 到红移 0.1。在 18% 的至少有五个星系以上恒星质量的星系群中，第三波段最亮的星系并不是处于引力势中心的星系；视线投影占这些情况的一半。偏心不会显着影响我们样本的整体平均质量密度分布或表面亮度分布：即使在中心模糊的光晕中，不同的中心选择也只会导致漫射组内光的总分数 fIGL 发生 1% 的变化。我们发现 IGL 与中心群星系的光度和晕质量有很强的相关性。因此，在中央星系光度的狭窄区域中堆叠组将使信号的物理解释比在广泛质量范围内组合系统更直接。
The diffuse light within galaxy groups and clusters provides valuable insight into the growth of massive cosmic structures. Groups are particularly interesting in this context, because they represent the link between galactic haloes and massive clusters. However, low surface brightness makes their diffuse light extremely challenging to detect individually. Stacking many groups is a promising alternative, but its physical interpretation is complicated by possible systematic variations of diffuse light profiles with other group properties. Another issue is the often ambiguous choice of group centre. We explore these challenges using mock observations for 497 galaxy groups and clusters with halo masses fromtoat redshift 0.1 from the Hydrangea cosmological hydrodynamic simulations. In 18 per cent of groups with at least five galaxies abovein stellar mass, ther-band brightest galaxy is not the one at the centre of the gravitational potential; line-of-sight projections account for half of these cases. Miscentring does not significantly affect the ensemble average mass density profile or the surface brightness profile for our sample: even within ambiguously centred haloes, different centring choices lead to only a 1 per cent change in the total fraction of diffuse intra-group light,fIGL. We find strong correlations offIGLwith the luminosity of the central group galaxy and halo mass. Stacking groups in narrow bins of central galaxy luminosity will therefore make the physical interpretation of the signal more straightforward than combining systems across a wide range of mass.