论文标题
GHz频率上的主要序列星系的红外线相关性及其在红移和恒星质量上的变化的模型
A model for the infrared-radio correlation of main-sequence galaxies at GHz frequencies and its variation on redshift and stellar mass
论文作者
论文摘要
根据MHz-GHz频率在Radio Continuum Luminiuments上，可以使用星形星系的红外线相关性（IRRC）来估计其恒星形成率（SFR）。对于将来的深度无线电调查中的应用，重要的是要知道IRRC是否持续到高红移Z处。先前的工作报告说，星形星系的1.4 GHz IRRC相关性几乎是z不变至z = 4，但在很大程度上取决于恒星质量M。这应考虑到基于无线电发光度的SFR校准。为了理解IRRC及其在较高z的特性的M依赖性背后的物理原因，我们构建了一个用于银河无线电发射的现象学模型。我们的模型基于发电机生成的磁场和稳态宇宙射线种群。它包括许多免费参数以及观察到的缩放关系。我们发现，红外与拉迪奥的光度比（z，m）相对于M的散布主要取决于银河半径的缩放，而Q（z，m）曲线的绝对值随着超级NOVA能量转换为磁场和磁场和宇宙射线的效率更高。降低宇宙射线注入光谱的斜率，ACR，导致较高的无线电发光度，从而降低了Q（z，m）曲线的绝对值。当超新星驱动的湍流效率为5％时，IRRC对M和Z的依赖性重现了观察到的依赖性，动能的10％被转化为磁能，而ACR = 3。对于中等至高m的星系，我们的模型（10^9.5-10^11 m_sun），我们的模型在IRRC中产生了几乎独立的Z。对于较低M（M = 10^8.5 m_sun）的星系，我们发现IR-Radio通量比随着红移的增加而增加。这与该质量箱中的观测数据相匹配，但是目前仅扩展到z〜1.5。
The infrared-radio correlation (IRRC) of star-forming galaxies can be used to estimate their star formation rate (SFR) based on the radio continuum luminosity at MHz-GHz frequencies. For its application in future deep radio surveys, it is crucial to know whether the IRRC persists at high redshift z. Previous works have reported that the 1.4 GHz IRRC correlation of star-forming galaxies is nearly z-invariant up to z=4, but depends strongly on stellar mass M. This should be taken into account for SFR calibrations based on radio luminosity. To understand the physical cause behind the M dependence of the IRRC and its properties at higher z, we constructed a phenomenological model for galactic radio emission. Our model is based on a dynamo-generated magnetic field and a steady-state cosmic ray population. It includes a number of free parameters as well as observed scaling relations. We find that the resulting spread of the infrared-to-radio luminosity ratio, q(z, M), with respect to M is mostly determined by the scaling of the galactic radius with M, while the absolute value of the q(z, M) curves decreases with more efficient conversion of supernova energy to magnetic fields and cosmic rays. Decreasing the slope of the cosmic ray injection spectrum, aCR, results in higher radio luminosity, decreasing the absolute values of the q(z, M) curves. Our model reproduces the observed dependence of the IRRC on M and z when the efficiency of supernova-driven turbulence is 5%, 10% of the kinetic energy is converted into magnetic energy, and aCR = 3. For galaxies with intermediate to high M (10^9.5-10^11 M_sun), our model results in an IRRC that is nearly independent of z. For galaxies with lower M (M=10^8.5 M_sun), we find that the IR-to-radio flux ratio increases with increasing redshift. This matches the observational data in that mass bin which currently, however, only extends to z~1.5.
