We construct one-zone steady-state models of cosmic ray (CR) injection, cooling, and escape over the entire dynamic range of the FIR-radio correlation (FRC), from normal galaxies to starbursts, over the redshift interval 0 <= z <= 10. Normal galaxies with low star-formation rates become radio-faint at high z, because Inverse Compton (IC) losses off the CMB cool CR electrons and positrons rapidly, suppressing their nonthermal radio emission. However, we find that this effect occurs at higher redshifts than previously expected, because escape, bremsstrahlung, ionization, and starlight IC losses act to counter this effect and preserve the radio luminosity of galaxies. The radio dimming of star-forming galaxies at high z is not just a simple competition between magnetic field energy density and the CMB energy density; the CMB must also compete with every other loss process. We predict relations for the critical redshift when radio emission is significantly suppressed compared to the z ~ 0 FRC as a function of star-formation rate per unit area. Additionally, we provide a quantitative explanation for the relative radio brightness of some high-z submillimeter galaxies. We show that at fixed star formation rate surface density, galaxies with larger CR scale heights are radio bright with respect to the FRC, because of weaker bremsstrahlung and ionization losses compared to compact starbursts. We predict that these "puffy starbursts" should have steeper radio spectra than compact galaxies with the same star-formation rate surface density. We find that radio bright submillimeter galaxies alone cannot explain the excess radio emission reported by ARCADE2, but they may significantly enhance the diffuse radio background with respect to a naive application of the z ~ 0 FRC.
Cross-Correlation of Diffuse Synchrotron and Large-Scale Structures
首次探索了利用射电同步辐射与大尺度结构示踪剂的互相关方法探测弥散IGM/WHIM。我们对两个红移切片（0.03 < z < 0.04和0.06 < z < 0.07）的34 x 34度区域的2 MASS星系与1.4 GHz波恩巡天的相应区域进行了互相关。在这个分析中，我们假设同步辐射表面亮度与星系的表面密度成线性比例。我们还抽样交叉关联函数使用24个相同大小的远场从波恩调查，以更好地评估噪声属性。虽然我们得到了零结果，但我们发现，通过添加由具有1（7）mK和7（49）mK的细丝（峰值）表面亮度的2 MASS图像加权的信号，将分别对0.03 < z < 0.04和0.06 < z < 0.07红移切片产生3 σ正相关。这些检测阈值对应于低至0.2 microG的最小能量磁场，接近于灯丝场值的一些理论预期。这种注入的信号也低于波恩调查的均方根噪声，并证明了这种技术的力量及其实用性，即将到来的敏感连续测量，如在阿雷西博的GALFACTS和那些计划与默奇森宽场阵列（MWA）。
Signatures of First Stars in Galaxy Surveys: Multi-Tracer Analysis of the Supersonic Relative Velocity Effect and the Constraints from the BOSS Power Spectrum Measurements
