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arXiv 1111.3066astro-ph.CO
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重子对晕质量函数的影响

The effects of baryons on the halo mass function

Weiguang Cui, Stefano Borgani, Klaus Dolag, Giuseppe Murante, Luca Tornatore

摘要:

本文分析了重子物理对晕质量函数的影响。分析是基于模拟的宇宙体积。除了暗物质(DM)的唯一模拟,我们还进行了其他两个流体动力学模拟。我们确定了晕使用球形密度算法和他们的质量计算在三个不同的密度(相对于临界),$Δ_c=200$,500和1500。我们发现晕质量之间的分数差在流体动力学和DM模拟几乎是恒定的,至少对于晕更大规模比$\log (M_{Δ_c} / \hMsun)\geq 13.5$。在这个范围内,流体动力学模拟中的质量增加在$Δ_c=500$约为4- 5%,在$Δ_c=200$约为$\sim 1$ -2%。非常有趣的是,这些差异几乎是相同的辐射和非辐射模拟。晕质量的这种变化引起晕质量函数(HMF)的相应变化。在$z=0$中,GH和CSF模拟的HMF接近DM,在$Δ_c = 200$中差异为$\mincir 3$ %,在$Δ_c=500$中差异为$\simeq 7$ %,在$Δ_c = 1500$中差异达到$\sim 10$ -20%。在该较高的过密度下,辐射情况下的HMF的增加相对于非辐射情况大约2倍。假设恒定的质量偏移以将HMF从流体动力学模拟重新缩放到DM模拟,使得相对于DM情况的HMF差异与零一致。我们的研究结果有有趣的影响,括号中的质量函数校准的不确定性与不确定的重子物理学,在宇宙学应用的星系团的未来大调查。(节录)

英文摘要:

We present an analysis of the effects of baryon physics on the halo mass function. The analysis is based on simulations of a cosmological volume. Besides a Dark Matter (DM) only simulation, we also carry out two other hydrodynamical simulations. We identified halos using a spherical overdensity algorithm and their masses are computed at three different overdensities (with respect to the critical one), $Δ_c=200$, 500 and 1500. We find the fractional difference between halo masses in the hydrodynamical and in the DM simulations to be almost constant, at least for halos more massive than $\log (M_{Δ_c} / \hMsun)\geq 13.5$. In this range, mass increase in the hydrodynamical simulations is of about 4-5 per cent at $Δ_c=500$ and $\sim 1$ - 2 per cent at $Δ_c=200$. Quite interestingly, these differences are nearly the same for both radiative and non-radiative simulations. Such variations of halo masses induce corresponding variations of the halo mass function (HMF). At $z=0$, the HMFs for GH and CSF simulations are close to the DM one, with differences of $\mincir 3$ per cent at $Δ_c = 200$, and $\simeq 7$ per cent at $Δ_c=500$, with $\sim 10$ - 20 per cent differences reached at $Δ_c = 1500$. At this higher overdensity, the increase of the HMF for the radiative case is larger by about a factor 2 with respect to the non--radiative case. Assuming a constant mass shift to rescale the HMF from the hydrodynamic to the DM simulations, brings the HMF difference with respect to the DM case to be consistent with zero. Our results have interesting implications to bracket uncertainties in the mass function calibration associated to the uncertain baryon physics, in view of cosmological applications of future large surveys of galaxy clusters. (Abridged)

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