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arXiv 1005.0639astro-ph.COastro-ph.GA
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随机原生磁场与暗物质晕的气体含量

Random Primordial Magnetic Fields and the Gas Content of Dark Matter Halos

Rafael S. de Souza, Luiz Felippe S. Rodrigues, Reuven Opher

摘要:

我们最近预测存在的随机原生磁场(RPMF)的形式随机取向的细胞与偶极状结构的细胞大小$L_0$和平均磁场$B_0$。在这里,我们调查模型的原始磁场具有类似的网状结构,和其他几何形状,不同的可能在$L_0$和$B_0$。研究了RPMF对第一星系形成的影响。过滤质量$M_F$是晕质量,低于这个质量,重子吸积被严重抑制。我们表明,这些RPMF可以影响星系的形成,通过改变过滤质量和重子气体的光环,$f_g$分数。这种效应在小星系中尤其强烈。我们发现,例如,对于一个共同运动的$B_0=0.1\muG$,和一个从$z_s=11$开始并在$z_e=8$结束的再电离时期,对于在$z=12$的$L_0=100\,\text{pc}$,$f_g$变得严重压抑,对于$M<10^7\msun$,而对于$B_0=0$,$f_g$变得严重压抑,只有小得多的质量,$M<10^5\msun$。我们认为,在高红移观测$M_F$和$f_g$可以提供原始磁场的强度和结构的信息。

英文摘要:

We recently predicted the existence of random primordial magnetic fields (RPMF) in the form of randomly oriented cells with dipole-like structure with a cell size $L_0$ and an average magnetic field $B_0$. Here we investigate models for primordial magnetic field with a similar web-like structure, and other geometries, differing perhaps in $L_0$ and $B_0$. The effect of RPMF on the formation of the first galaxies is investigated. The filtering mass, $M_F$, is the halo mass below which baryon accretion is severely depressed. We show that these RPMF could influence the formation of galaxies by altering the filtering mass and the baryon gas fraction of a halo, $f_g$. The effect is particularly strong in small galaxies. We find, for example, for a comoving $B_0=0.1\muG$, and a reionization epoch that starts at $z_s=11$ and ends at $z_e=8$, for $L_0=100\,\text{pc}$ at $z=12$, the $f_g$ becomes severely depressed for $M<10^7\msun$, whereas for $B_0=0$ the $f_g$ becomes severely depressed only for much smaller masses, $M<10^5\msun$. We suggest that the observation of $M_F$ and $f_g$ at high redshifts can give information on the intensity and structure of primordial magnetic fields.

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。

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