利用uGMRT 3频段研究GAMA-23天区弥散银河同步辐射的射电源种群与空间特征
Investigating radio source population and spatial characteristics of diffuse Galactic synchrotron emission in the GAMA-23 field with uGMRT Band-3
- Indian Institute of Technology Indore（印度印多尔理工学院）
- The University of Manchester（曼彻斯特大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究利用uGMRT 3频段观测GAMA-23天区，首次推导匹配源谱指数、表征南天区325 MHz处DGSE特性，为SKA前景建模提供先例。
AI中文摘要：
我们呈现了uGMRT 3频段对银河与质量联盟（Galaxy and Mass Assembly, GAMA）-23天区的观测结果。这些观测共包含50个指向，总时长33小时，中心频率为325 MHz，每个指向的观测时长约56分钟。由这些指向拼接而成的最终图像，中心离源的均方根噪声为109 μJy/束，覆盖面积为65.31平方度，分辨率为15.8角秒。这一广域深场观测提供了包含5741个流量密度≥5σ的射电源的星表。我们呈现了与高频ASKAP EMU巡天重叠的互补uGMRT观测数据，首次推导了GAMA-23天区匹配源的谱指数。我们利用6个不同纬度的目标指向，研究了GAMA-23天区弥散银河同步辐射（diffuse Galactic synchrotron emission, DGSE）的统计特性，以幂律形式拟合DGSE：$C_{\rm l} = A(1000/{\rm l})^\beta$。我们得到的DGSE振幅范围为$A = 1-20\rm mK^2$，$\beta$的变化范围为1.5-2.4。本研究是首次在325 MHz频段对南天区DGSE进行表征的工作之一，为即将到来的SKA（平方公里阵列）高灵敏度射电观测所需的前景建模树立了先例。
英文摘要：
We present upgraded Giant Meterwave Radio Telescope (uGMRT) Band-3 observations of the Galaxy and Mass Assembly (GAMA)-23 field. The observations consist of a total of 33 hours spread over 50 pointings, corresponding to $\sim$56 minutes per pointing at the central frequency of 325 MHz. The final image mosaicked from these pointings has a central off-source RMS noise of $109\,μ\mathrm{Jy}/\mathrm{beam}$ and covers an area $65.31\,\text{deg}^2$ with a resolution of $15.8''$. This wide-area deep-field observation provides a radio source catalog of 5741 sources with flux densities ${\geq}5σ$. We present complementary uGMRT observations overlapping with the high-frequency Australian Square Kilometre Array Pathfinder Evolutionary Map of the Universe survey. We derived the spectral index from the matched sources in the GAMA-23 field for the first time. We have studied the statistical properties of diffuse Galactic synchrotron emission (DGSE) in the GAMA-23 field using six different latitude target pointings. We fitted DGSE in the form of power law $C_{\ell} = A(1000/{\ell})^{β}$. Our DGSE amplitude range of $A = 1-20\,{\text{mK}}^2$ and $β$ varies between $1.5$ and $2.4$. This work presents one of the first characterizations of DGSE in the southern sky at 325 MHz, setting a precedent for foreground modeling required for sensitive radio observations with the upcoming SKA.
