论文标题
加里龙幽灵冷凝物模型中非线性结构和球形崩溃的生长
Growth of non-linear structures and spherical collapse in the Galileon Ghost Condensate model
论文作者
论文摘要
我们介绍了一项详细的研究，该研究对Galileon幽灵冷凝物（GGC）模型中球形物质过度密度的崩溃和大规模结构的非线性生长进行了详细研究。该模型是立方协变量Galileon（G3）的扩展，其中包括$ $（\nabla_μxtyper\ nabla \ nabla^μϕ）^2 $的场导数。我们发现，立方术语激活了主要物理量的修改，其时间演变会受到附加项的强烈影响。确实，GGC模型在线性化的临界密度对比度，非线性有效重力耦合以及与G3相对于G3的病毒过度密度中显示了很大的减轻作用，但仍然可以保持相对于标准$λ$ CDM宇宙学模型，例如。线性临界密度对比度和病毒过度密度都比$λ$ CDM中的密度大。然后使用球形塌陷模型的结果来预测光环质量功能，非线性物质和镜头功率谱的演变。在低质量下，GGC模型相对于$λ$ CDM的对象少了约10％，在$ z> 0 $的较高质量上，它预测10％（$ z = 0.5 $）-20％（$ z = 1 $）每个共同量的对象。使用现象学方法，包括在物质功率谱中的筛选效果，我们表明，由重力修饰引起的差异很大程度上取决于筛选量表，相对于$λ$ CDM，差异可以高达20％。这些差异转化为镜头功率谱，在质量上，相对于标准宇宙学模型的最大差异是$ \ ell <10^3 $。根据筛选量表，它们在较大的角度尺度上的最高可高达25％，然后减少$ \ ell $。这些结果是从每个模型的线性宇宙学数据中获得最佳拟合参数的。
We present a detailed study of the collapse of a spherical matter overdensity and the non-linear growth of large scale structures in the Galileon ghost condensate (GGC) model. This model is an extension of the cubic covariant Galileon (G3) which includes a field derivative of type $(\nabla_μϕ\nabla^μϕ)^2$ in the Lagrangian. We find that the cubic term activates the modifications in the main physical quantities whose time evolution is then strongly affected by the additional term. Indeed, the GGC model shows largely mitigated effects in the linearised critical density contrast, non-linear effective gravitational coupling and the virial overdensity with respect to G3 but still preserves peculiar features with respect to the standard $Λ$CDM cosmological model, e.g. both the linear critical density contrast and the virial overdensity are larger than those in $Λ$CDM. The results of the spherical collapse model are then used to predict the evolution of the halo mass function, non-linear matter and lensing power spectra. While at low masses the GGC model presents about 10% fewer objects with respect to $Λ$CDM, at higher masses for $z>0$ it predicts 10% ($z=0.5$)-20% ($z=1$) more objects per comoving volume. Using a phenomenological approach to include the screening effect in the matter power spectrum, we show that the difference induced by the modifications of gravity are strongly dependent on the screening scale and that differences can be up to 20% with respect to $Λ$CDM. These differences translate to the lensing power spectrum where qualitatively the largest differences with respect to the standard cosmological model are for $\ell<10^3$. Depending on the screening scale, they can be up to 25% on larger angular scales and then decrease for growing $\ell$. These results are obtained for the best fit parameters from linear cosmological data for each model.
