标题： 研究恒星形成星系的远红外/无线电相关性至红移z=3 显示英文标题

标题： Investigating the Far-IR/Radio Correlation of Star Forming Galaxies to z=3

摘要： 为了研究高红移处的远红外/射电波段相关性，我们通过红移和星系类型（活动星系核AGN或恒星形成星系SFG）研究了来自13^H XMM-Newton/Chandra深场的亚mJy量级射电源在斯皮策70微米/远红外（far-IR）波段的性质。 我们直接探测到70微米对应源（显著性大于3σ）的比例为22.5%（92/408），而对于其余的射电源，我们按照红移和星系类型进行了堆叠分析。 对于在70微米波段被探测到的源，我们发现观测到的流量比q70的中位数和散布与文献中的先前结果相似，但q70随红移增加有轻微下降。 在70微米波段被探测到的射电源中，8/92个已被分类为AGN，但其中两个可能是SFG。 对于堆叠的源，我们在每个红移区间内都探测到了SFGs，这表明它们的平均流量密度大约比最初的70微米探测极限低一个因子~5。 对于堆叠的AGN，我们只在最高的红移区间（1<~z<~5）内获得了探测，这可能是因为我们正在采样与AGN相关的热尘埃，在静止框架下为12-35微米波段。 对于SFGs（无论是否在70微米波段被检测到）组合得到的q70的观测平均值随着红移逐渐减小，这与基于本地SFGs经验光谱能量分布（SEDs）得出的轨迹一致。 经过更仔细的检查并与适当亮度的轨迹进行比较，低红移时q70的值大致相符。 然而，在z~1时，超亮红外星系（ULIRGs）的观测q70值比本地ULIRGs轨迹所见值低2σ，这意味着本地和z~1 ULIRGs之间的SED存在差异。 在更高的红移上，轨迹的汇聚以及q70的更高不确定性不允许我们确定这种差异是否持续存在。 显示英文摘要

摘要： In order to examine the far-IR/radio correlation at high redshift we have studied the Spitzer 70um/far-infrared (far-IR) properties of sub-mJy radio sources from the 13^H XMM-Newton/Chandra Deep Field by redshift and galaxy type: active galactic nucleus (AGN) or star forming galaxy (SFG). We directly detect 70um counterparts (at >3sigma significance) for 22.5% (92/408) of the radio sources, while for the rest we perform stacking analysis by redshift and galaxy type. For the sources detected at 70um we find that the median and scatter of the observed flux density ratio, q70, are similar to previous results in the literature, but with a slight decrease in q70 towards higher redshifts. Of the radio sources detected at 70um 8/92 were already classified as AGN, but two of which maybe SFGs. For the stacked sources we obtain a detection for the SFGs at every redshift bin which implies they have mean flux densities a factor ~5 below the original 70um detection limit. For the stacked AGN we obtain a detection only in our highest redshift bin (1<~z<~5) where we may be sampling hot dust associated with the AGN at rest-frame 12-35um. The combined observed mean value of q70 for the SFGs (detected and non-detected at 70um) decreases gradually with redshift, consistent with tracks derived from empirical spectral energy distributions (SEDs) of local SFGs. Upon closer inspection and when comparing with tracks of appropriate luminosity, the values of q70 broadly agree at low redshift. However, at z~1, the observed q70 (for ULIRGs) is 2sigma below the value seen for local ULIRGs tracks, implying a difference in the SED between local and z~1 ULIRGs. At higher redshifts, the convergence of the tracks and the higher uncertainties in q70 do not allow us to determine if such a difference persists.