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arXiv 1909.04690astro-ph.GAastro-ph.CO
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通过旋转kSZ效应探测气态星系晕

Probing gaseous galactic halos through the rotational kSZ effect

José Manuel Zorrilla Matilla, Zoltán Haiman

摘要:

旋转运动学Sunyaev-Zeldovich(rkSZ)信号,由前景星系的气体晕(旋转的“大气”)印在宇宙微波背景(CMB)上,将是星系形成的新探测器。虽然信号太弱,在个别星系检测,我们分析了其统计检测的可行性,通过堆叠CMB数据的许多星系的自旋取向可以估计光谱。我们使用一个“乐观”的模型,其中完全电离的大气包含宇宙重子分数和旋转在晕的圆速度$v_{\rm circ}$,和一个更现实的模型,基于流体动力学模拟,与多相大气旋转在一个分数的$v_{\rm circ}$。我们将现实的噪声估计纳入我们的分析。使用低红移星系的性质从MANGA光谱调查(与中等晕质量的$6.6\times10^{11}\,M_{\odot}$),和CMB数据质量从普朗克,我们发现,$3σ$检测将需要几个$\times 10^4$星系,即使在乐观的模型。这对目前的调查来说太高了,但即将到来的更高角分辨率的CMB实验将大大降低要求:在$\sim10$ deg $^2$中堆叠星系自旋上的CMB数据可以排除乐观的模型,而$\approx$ 350 deg $^2$将足以用ACT进行$3σ$探测。作为概念验证,我们将普朗克数据叠加在$\approx2,000$ MaNGA星系的位置上,与星系的投影自旋对齐,并按比例缩放到它们的晕的角度大小。我们排除了平均温度偶极子大于$\approx1.9\,μ$ K周围场螺旋星系。

英文摘要:

The rotational kinematic Sunyaev-Zeldovich (rkSZ) signal, imprinted on the cosmic microwave background (CMB) by the gaseous halos (spinning "atmospheres") of foreground galaxies, would be a novel probe of galaxy formation. Although the signal is too weak to detect in individual galaxies, we analyze the feasibility of its statistical detection via stacking CMB data on many galaxies for which the spin orientation can be estimated spectroscopically. We use an "optimistic" model, in which fully ionized atmospheres contain the cosmic baryon fraction and spin at the halo's circular velocity $v_{\rm circ}$, and a more realistic model, based on hydrodynamical simulations, with multi-phase atmospheres spinning at a fraction of $v_{\rm circ}$. We incorporate realistic noise estimates into our analysis. Using low-redshift galaxy properties from the MaNGA spectroscopic survey (with median halo mass of $6.6\times10^{11}\,M_{\odot}$), and CMB data quality from Planck, we find that a $3σ$ detection would require a few$\times 10^4$ galaxies, even in the optimistic model. This is too high for current surveys, but upcoming higher-angular resolution CMB experiments will significantly reduce the requirements: stacking CMB data on galaxy spins in a $\sim10$ deg$^2$ can rule out the optimistic models, and $\approx$350 deg$^2$ will suffice for a $3σ$ detection with ACT. As a proof-of-concept, we stacked Planck data on the position of $\approx2,000$ MaNGA galaxies, aligned with the galaxies' projected spin, and scaled to their halos' angular size. We rule out average temperature dipoles larger than $\approx1.9\,μ$K around field spiral galaxies.

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