arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 1104.5040astro-ph.CO
收藏

MOND中星系团的丰度:大质量中微子的宇宙学模拟

The abundance of galaxy clusters in MOND: Cosmological simulations with massive neutrinos

Garry W. Angus, Antonaldo Diaferio

摘要:

我们提出了一个新的粒子网格宇宙学N体代码精确求解修改后的泊松方程的准线性制定的MOND。我们生成了Angus(2009)宇宙学模型的初始条件,该模型与LCDM模型相同,只是冷暗物质被切换为单一种类的热不育中微子。对于一个有256^3个粒子的(512 Mpc/h)^3盒子,我们将初始条件设为z=250,然后将它们演化到z=0。我们清楚地证明了MOND在热暗物质宇宙学中发展大尺度结构的必要性,并反驳了MOND不能形成星系团的天真期望。我们发现可以形成正确数量级的X射线团簇(T_X > 4.5keV),但是我们高估了非常丰富的团簇的数量,而严重低估了低质量团簇的数量。后者是一个缺点,我们的模拟分辨率,而我们建议,过度生产的非常丰富的集群可能会被阻止,通过将MOND加速常数随红移和膨胀的历史,不能描述通常的弗里德曼模型。我们提出的证据表明,我们的模拟集群的密度分布与MOND中观察到的X射线集群是兼容的。这还有待观察,如果低质量端的集群质量函数可以复制,如果高密度的暗物质在中央20千秒差距的集团和星系团,在MOND框架中测量,可以实现。作为最后一个测试,我们计算了10 Mpc以内的晕对之间的相对速度,发现像子弹状星团这样速度大于3000 km/s的对可以毫无困难地形成。

英文摘要:

We present a new Particle-Mesh cosmological N-body code for accurately solving the modified Poisson equation of the Quasi Linear formulation of MOND. We generate initial conditions for the Angus (2009) cosmological model, which is identical to LCDM except that the cold dark matter is switched for a single species of thermal sterile neutrinos. We set the initial conditions at z=250 for a (512 Mpc/h)^3 box with 256^3 particles and we evolve them down to z=0. We clearly demonstrate the necessity of MOND for developing the large scale structure in a hot dark matter cosmology and contradict the naive expectation that MOND cannot form galaxy clusters. We find that the correct order of magnitude of X-ray clusters (with T_X > 4.5 keV) can be formed, but that we overpredict the number of very rich clusters and seriously underpredict the number of lower mass clusters. The latter is a shortcoming of the resolution of our simulations, whereas we suggest that the over production of very rich clusters might be prevented by incorporating a MOND acceleration constant that varies with redshift and an expansion history that cannot be described by the usual Friedmann models. We present evidence that suggests the density profiles of our simulated clusters are compatible with those of observed X-ray clusters in MOND. It remains to be seen if the low mass end of the cluster mass function can be reproduced and if the high densities of dark matter in the central 20 kpc of groups and clusters of galaxies, measured in the MOND framework, can be achieved. As a last test, we computed the relative velocity between pairs of halos within 10 Mpc and find that pairs with velocities larger than 3000 km/s like the bullet cluster, can form without difficulty.

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。

↑