Probing the circumgalactic baryons through cross-correlations
Probing the circumgalactic baryons through cross-correlations
复制标题
通过互相关探测环银河系重子
DOI：
10.1093/mnras/stv2750
复制
发表时间：
2015
影响因子：
4.8
通讯作者：
J. Silk
中科院分区：
文献类型：
--
作者：
Priyanka Singh;S. Majumdar;B. Nath;A. Réfrégier;J. Silk
我们研究的交叉相关性的星系分布，Sunyaev-Zel'dovich（SZ）和X射线功率谱的星系从当前和即将到来的调查，并显示这些是很好的探针的性质，即范围，演化和能量，环星系介质（CGM）。我们考虑的贡献，只有在这些星系中的气体冷却的时间尺度大于晕破坏的时间尺度的热气体。对于一个平坦的压力分布，SZ交叉功率谱显示出在l值处的振荡，对应于小于星系维里半径的-2倍的长度尺度。这些振荡对CGM的压力分布的陡度敏感，并且对于足够陡的分布消失。因此，SZ信号的这种性质可以用于约束CGM的压力分布。类似的振荡也存在于X射线交叉功率谱，然而，更敏感的密度分布。结合SPT-DES和eROSITADES/eROSITA-LSST巡天，分别预测了互关联星系分布、SZ和X射线信号的可探测性。我们发现，对于SPT-DES测量，对于平坦的密度和温度分布，信噪比（SNR）在高质量和红移处达到峰值，SNR为9，约为Mh 10 13 h-1 M⊙和z 1.5-2。对于高质量和低红移的星系，SNR也是显著的（> 3）。eROSITA-DES（eROSITA-LSST）调查的SNR峰值为-6（12）。我们还进行了Fisher矩阵分析，发现在存在（不存在）未知的气体部分的红移演化的情况下，CGM中的气体部分可以被SPT-DES和eROSITA-DES测量的精度限制在-34%（23%）和-23%（14%）。最后，我们证明了交叉相关的SZ-星系和X射线-星系功率谱可以用作CGM能量学的强有力的探针，并可能区分最近在文献中提出的不同反馈模型;例如，人们可以区分“无活动星系核反馈”的情况下，由“固定速度的热风”在大于3σ的CGM。
We study the cross-correlation of distribution of galaxies, the Sunyaev-Zel’dovich (SZ) and X-ray power spectra of galaxies from current and upcoming surveys and show these to be excellent probes of the nature, i.e. extent, evolution and energetics, of the circumgalactic medium (CGM). We consider the contributions from the hot gas in only those galaxies in which the gas cooling time-scale is larger than the halo destruction time-scale. For a flat pressure profile, the SZ cross power spectrum shows oscillations at l-values corresponding to the length scales smaller than � 2 times the virial radius of the galaxy. These oscillations are sensitive to the steepness of the pressure profile of the CGM and vanish for a sufficiently steep profile. This property of the SZ signal can, thus, be used to constrain the pressure profile of the CGM. Similar oscillations are also present in the X-ray cross power spectrum which is, however, more sensitive to the density profile. We forecast the detectability of the cross-correlated galaxy distribution, SZ and X-ray signals by combining SPT-DES and eROSITADES/eROSITA-LSST surveys, respectively. We find that, for the SPT-DES survey, the signal-to-noise ratio (SNR) peaks at high mass and redshift with SNR � 9 around Mh � 10 13 h −1 M⊙ and z � 1.5–2 for flat density and temperature profiles. The SNR is also significant (> 3) for high mass and low redshift galaxies. The SNR peaks at � 6(12) for the eROSITA-DES (eROSITA-LSST) surveys. We also perform a Fisher matrix analysis and find that the gas fraction in the CGM can be constrained to a precision of � 34%(23%) by the SPT-DES and � 23%(14%) by the eROSITA-DES surveys in the presence (absence) of an unknown redshift evolution of the gas fraction. Finally, we demonstrate that the cross-correlated SZ-galaxy and X-ray-galaxy power spectrum can be used as powerful probes of the CGM energetics and potentially discriminate between different feedback models recently proposed in the literature; for example, one can distinguish a ‘no AGN feedback’ scenario from a CGM energized by ‘fixed-velocity hot winds’ at greater than 3σ.