变色龙暗物质的静态结构对矮球状星系核的解释
Static structure of chameleon dark Matter as an explanation of dwarf spheroidal galactic core
摘要：
提出了一种新的机制来解释最近观测到的富含暗物质的矮球状星系的核心暗物质密度分布。在我们的方案中，暗物质粒子的质量逐渐减少的功能，由于其与变色龙标量的中心的距离。当距离银心较近时，吸引标量第五力的强度远大于引力，并被暗物质云的费米压所平衡，从而得到暗物质晕的平衡静态位形。与孤立子星或费米子Q星的情况一样，暗物质晕的稳定性是在标量达到一个静态轮廓并在远离星系中心的地方达到一个渐近值时得到的。对于简单标量-暗物质相互作用势和二次标量自相互作用势，我们证明了暗物质的行为与冷暗物质（CDM）完全相同，但在距离星系中心几个$\rm{kpc}$处，它变得更轻，费米压力不再可以忽略.利用高斯-费米近似，数值求解了标量场、费米子质量和暗物质能量密度随距离的径向静态分布。我们发现，对于由超轻标量介导的第五种力，有可能获得朝向星系中心的平坦的暗物质密度分布。在我们的方案中，第五种力在距离银河系中心$ r \geq 1\, \rm{kpc}$处可以忽略，暗物质可以简单地被视为超过这个距离的重非相对论粒子，从而在大尺度上再现了CDM的成功。
英文摘要：
We propose a novel mechanism which explains cored dark matter density profile in recently observed dark matter rich dwarf spheroidal galaxies. In our scenario, dark matter particle mass decreases gradually as function of distance towards the center of a dwarf galaxy due to its interaction with a chameleon scalar. At closer distance towards galactic center the strength of attractive scalar fifth force becomes much stronger than gravity and is balanced by the Fermi pressure of dark matter cloud, thus an equilibrium static configuration of dark matter halo is obtained. Like the case of soliton star or fermion Q-star, the stability of the dark matter halo is obtained as the scalar achieves a static profile and reaches an asymptotic value away from the galactic center. For simple scalar-dark matter interaction and quadratic scalar self interaction potential, we show that dark matter behaves exactly like cold dark matter (CDM) beyond few $\rm{kpc}$ away from galactic center but at closer distance it becomes lighter and fermi pressure cannot be ignored anymore. Using Thomas-Fermi approximation, we numerically solve the radial static profile of the scalar field, fermion mass and dark matter energy density as a function of distance. We find that for fifth force mediated by an ultra light scalar, it is possible to obtain a flattened dark matter density profile towards galactic center. In our scenario, the fifth force can be neglected at distance $ r \geq 1\, \rm{kpc}$ from galactic center and dark matter can be simply treated as heavy non-relativistic particles beyond this distance, thus reproducing the success of CDM at large scales.
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。
