通过tSZ效应和弱引力透镜揭示星系群中存在热压强亏缺的证据
Evidence for a thermal pressure deficit in galaxy groups from the tSZ effect and weak lensing
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中文总结 AI 辅助
本研究结合tSZ效应与弱引力透镜测量，发现FLAMINGO模拟高估星系群热压强两倍，提示存在缺失的非热压强支撑或流体静力学平衡偏离。
中文摘要 AI 辅助
热Sunyaev-Zel'dovich（tSZ）效应的测量尚未能对星系团内介质气体的热力学状态形成一致的描述：前景污染和不确定的暗物质晕质量使其解释变得复杂。我们对暗能量光谱仪（DESI）的亮红星系（LRG）样本周围的tSZ效应进行了新的测量，结合星系-星系引力透镜（GGL）测量，实现了与最先进流体动力学模拟的同类比较。我们利用阿塔卡马宇宙学望远镜（ACT）单通道温度图直接建模目标星系的尘埃和射电发射，可靠地分离出tSZ信号，大幅降低了天体物理前景带来的不确定性。在暗物质晕质量$M_{500}=10^{13}-10^{14}~M_\bigodot$、红移范围$0.4<z<1$的情况下，我们发现基准1立方吉秒差距的FLAMINGO模拟在$\leq3'$（即$z=0.7$时$\leq4R_{500}$）处显著高估了观测到的tSZ信号。即使是气体驱逐最强的模拟（该模拟成功重现了同一样本动力学SZ测量得出的气体密度），仍高估了热压强。由于最强反馈模型已能重现观测到的气体密度，剩余的差异仅靠额外的气体耗尽难以解释。相反，当前流体动力学模拟似乎将星系群的热压强高估了两倍，这指向缺失的非热压强支撑或流体静力学平衡的显著偏离。
英文摘要
Measurements of the thermal Sunyaev-Zel'dovich (tSZ) effect have yet to form a consistent picture of the thermodynamic state of the gas in the intracluster medium: their interpretation is complicated by foreground contamination and uncertain halo masses. We present new measurements of the tSZ effect around the Dark Energy Spectroscopic Instrument (DESI) Luminous Red Galaxy (LRG) sample, together with galaxy-galaxy lensing (GGL) measurements that enable a like-with-like comparison to state-of-the-art hydrodynamical simulations. We robustly isolate the tSZ signal by directly modeling the dust and radio emission of the target galaxies using the Atacama Cosmology Telescope (ACT) single-channel temperature maps, substantially reducing uncertainties from astrophysical foregrounds. Across halo masses $M_{500}=10^{13}-10^{14}~M_\odot$ and redshifts $0.4<z<1$, we find that the fiducial 1 Gpc$^3$ FLAMINGO simulation significantly overpredicts the observed tSZ signal at $\lesssim3'$ (i.e., $\lesssim 4\,R_{500}$ at $z=0.7$). Even the simulation with the strongest gas expulsion---which successfully reproduces the gas density inferred from kinetic SZ measurements of the same galaxy sample---overpredicts the thermal pressure. Because the strongest feedback model already reproduces the observed gas density, the remaining discrepancy is difficult to explain with additional gas depletion alone. Instead, current hydrodynamical simulations appear to overpredict the thermal pressure of galaxy groups by a factor of two, pointing toward missing non-thermal pressure support or significant departures from hydrostatic equilibrium.
