arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1003.2755astro-ph.CO
收藏

按恒星质量选择的星系的成团特性:从z=0到z=2的大质量星系中亮物质和暗物质之间的联系被打破

Clustering properties of galaxies selected in stellar mass: Breaking down the link between luminous and dark matter in massive galaxies from z=0 to z=2

S. Foucaud, C. J. Conselice, W. G. Hartley, K. P. Lane, S. P. Bamford, O. Almaini, K. Bundy

摘要:

我们研究了从帕洛玛天文台宽视场红外巡天中选取的恒星质量M*> 10^10 M(太阳)的18,482个星系在红移0.4<z<2.0时的成团情况。我们研究这些恒星质量选择的样本作为红移和恒星质量的函数的聚类特性,并讨论了测量的聚类强度的影响,他们可能的晕质量。我们发现,具有高恒星质量的星系有一个逐步更高的集群强度,和振幅,比星系较低的恒星质量。我们还发现,在一个固定的恒星质量范围内的星系有一个较高的集群强度在较高的红移。我们进一步使用我们测量的聚集强度,结合Mo & White(2002)的模型,来确定这些星系的暗物质晕的平均总质量。我们的结论是,在我们的样本中的所有星系的恒星质量总质量比总是低于普遍重子质量分数。使用我们的研究结果,并从文献汇编,我们还表明,有一个很强的相关性之间的恒星质量总质量比和派生晕质量的中心星系,这样,更大的质量晕包含一个较低的分数,其质量的形式在我们的整个红移范围内的恒星。对于质量M(晕)> 10^13 M(太阳)的晕中的中心星系,我们发现这个比值<0.02,比普遍的重子质量分数低得多。我们表明,剩余的重子质量部分包括在这些晕中的卫星星系内的恒星,并作为弥漫的热和温暖的气体。我们还发现,在一个固定的恒星质量,恒星的总质量比增加在较低的红移。这表明,恒星质量固定的星系形成较晚的低质量暗物质晕,而较早的大质量晕。我们将其解释为“晕圈缩小”效应,然而,这种演变的一部分可能归因于晕圈组装偏差。

英文摘要:

We present a study on the clustering of a stellar mass selected sample of 18,482 galaxies with stellar masses M*>10^10M(sun) at redshifts 0.4<z<2.0, taken from the Palomar Observatory Wide-field Infrared Survey. We examine the clustering properties of these stellar mass selected samples as a function of redshift and stellar mass, and discuss the implications of measured clustering strengths in terms of their likely halo masses. We find that galaxies with high stellar masses have a progressively higher clustering strength, and amplitude, than galaxies with lower stellar masses. We also find that galaxies within a fixed stellar mass range have a higher clustering strength at higher redshifts. We furthermore use our measured clustering strengths, combined with models from Mo & White (2002), to determine the average total masses of the dark matter haloes hosting these galaxies. We conclude that for all galaxies in our sample the stellar-mass-to-total-mass ratio is always lower than the universal baryonic mass fraction. Using our results, and a compilation from the literature, we furthermore show that there is a strong correlation between stellar-mass-to-total-mass ratio and derived halo masses for central galaxies, such that more massive haloes contain a lower fraction of their mass in the form of stars over our entire redshift range. For central galaxies in haloes with masses M(halo)>10^13M(sun) we find that this ratio is <0.02, much lower than the universal baryonic mass fraction. We show that the remaining baryonic mass is included partially in stars within satellite galaxies in these haloes, and as diffuse hot and warm gas. We also find that, at a fixed stellar mass, the stellar-to-total-mass ratio increases at lower redshifts. This suggests that galaxies at a fixed stellar mass form later in lower mass dark matter haloes, and earlier in massive haloes. We interpret this as a "halo downsizing" effect, however some of this evolution could be attributed to halo assembly bias.

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。

↑