arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1502.02043astro-ph.CO
收藏

星系对与银河丝排成一列

Galaxy pairs align with galactic filaments

Elmo Tempel, Antti Tamm

摘要:

上下文引力坍缩理论和数值模拟表明,大尺度星系细丝内的速度场主要由沿细丝的运动所控制。目标。我们的目的是检查观测数据是否揭示了任何优先取向的星系对相对于潜在的灯丝作为一个结果的各向异性的速度场。方法.我们使用从斯隆数字巡天数据中识别出的星系对和星系细丝。对于细丝提取,我们使用基于标记点处理技术的Bisous模型。在暗条探测过程中,我们使用每对星系的中心点代替星系的位置,以避免暗条结构中星系对取向的内在影响。对于位于暗条内的星系对(3012例),我们计算了每对星系与其主暗条的连线之间的夹角。为了避免红移空间失真,角度是在天空的平原上测量的。结果排列分析表明,星系对的取向与它们的主灯丝有很强的相关性。松散对的对齐信号更强,与随机分布相比,对齐对至少过量25%。从观测数据中测得的星系对和暗条的排列与Millennium模拟中的排列很好地一致,从而为ΛCDM形式提供了支持。

英文摘要:

Context. Gravitational collapse theory and numerical simulations suggest that the velocity field within large-scale galaxy filaments is dominated by motions along the filaments. Aims. Our aim is to check whether observational data reveal any preferred orientation of galaxy pairs with respect to the underlying filaments as a result of the expectedly anisotropic velocity field. Methods. We use galaxy pairs and galaxy filaments identified from the Sloan Digital Sky Survey data. For filament extraction, we use the Bisous model that is based the marked point process technique. During the filament detection, we use the centre point of each pair instead of the positions of galaxies to avoid a built-in influence of pair orientation on the filament construction. For pairs lying within filaments (3012 cases), we calculate the angle between the line connecting galaxies of each pair and their host filament. To avoid redshift-space distortions, the angle is measured in the plain of the sky. Results. The alignment analysis shows that the orientation of galaxy pairs correlates strongly with their host filaments. The alignment signal is stronger for loose pairs, with at least 25% excess of aligned pairs compared to a random distribution. The alignment of galaxy pairs and filaments measured from the observational data is in good concordance with the alignment in the Millennium simulation and thus provides support to the ΛCDM formalism.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑