热SZ断层成像
The thermal SZ tomography
摘要：
热Sunyaev-Zel'dovich（tSZ）效应直接测量沿视线积分的自由电子的热压，因此包含关于宇宙热历史的有价值的信息。然而，红移信息纠缠在沿视线的投影中。这种投影效应严重降低了tSZ效应重建热历史的能力。我们调查的tSZ层析成像技术，以恢复否则丢失的红移信息，通过互相关的tSZ效应与已知的红移星系，或者与弱透镜层析重建的物质分布。通过绝热流体动力学模拟和辐射冷却、恒星形成和超新星反馈等附加的气体物理模拟，详细研究了气体热压力的三维分布及其与物质分布的关系。(1)我们发现气体压力和物质分布之间有很强的相关性，在k处具有典型的互相关系数r ~ 0.7。3 h/Mpc和z < 2。这种紧密的相关性将使SZ调查（如普朗克，ACT和SPT）与透镜调查（如DES和LSST）之间的稳健互相关测量在~20-100σ水平。(2)我们提出了一种层析成像技术，将测得的互相关转换为每个红移仓中的气体对tSZ功率谱的贡献。在我们的模拟中发现，由于胃物理学对r的影响约为1%，因此胃物理学的不确定性可能会在约2%的水平上影响重建。然而，我们发现，相同的胃物理影响的tSZ功率谱在~ 40%的水平，所以它是强大的推断胃物理从重建的红移解决的贡献。
英文摘要：
The thermal Sunyaev-Zel'dovich (tSZ) effect directly measures the thermal pressure of free electrons integrated along the line of sight and thus contains valuable information on the thermal history of the universe. However, the redshift information is entangled in the projection along the line of sight. This projection effect severely degrades the power of the tSZ effect to reconstruct the thermal history. We investigate the tSZ tomography technique to recover this otherwise lost redshift information by cross correlating the tSZ effect with galaxies of known redshifts, or alternatively with matter distribution reconstructed from weak lensing tomography. We investigate in detail the 3D distribution of the gas thermal pressure and its relation with the matter distribution, through our adiabatic hydrodynamic simulation and the one with additional gastrophysics including radiative cooling, star formation and supernova feedback. (1) We find a strong correlation between the gas pressure and matter distribution, with a typical cross correlation coefficient r ~ 0.7 at k . 3h/Mpc and z < 2. This tight correlation will enable robust cross correlation measurement between SZ surveys such as Planck, ACT and SPT and lensing surveys such as DES and LSST, at ~20-100σ level. (2) We propose a tomography technique to convert the measured cross correlation into the contribution from gas in each redshift bin to the tSZ power spectrum. Uncertainties in gastrophysics may affect the reconstruction at ~ 2% level, due to the ~ 1% impact of gastrophysics on r, found in our simulations. However, we find that the same gastrophysics affects the tSZ power spectrum at ~ 40% level, so it is robust to infer the gastrophysics from the reconstructed redshift resolved contribution.
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