Spectral index of the diffuse radio background between 50 and 100 MHz
Spectral index of the diffuse radio background between 50 and 100 MHz
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50 至 100MHz 之间的漫射无线电背景的频谱指数
DOI：
10.1093/mnras/sty3410
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发表时间：
2018
影响因子：
4.8
通讯作者：
J. Bowman
中科院分区：
文献类型：
--
作者：
T. Mozdzen;N. Mahesh;R. Monsalve;A. Rogers;J. Bowman
我们报告的光谱指数之间的50和100 MHz的扩散无线电发射的数据收集的实验，以检测全球EoR签名（EDGES）低波段系统的两个实现。EDGES采用宽波束指向天顶的偶极天线，其中心位于$-26.7 ^\circ $的十分位数。我们测量了天空亮度温度，作为2016年9月14日至2017年8月27日期间获得的244个夜晚数据的EDGES光束平均频率的函数。我们推导出的光谱指数，$\beta$，作为当地恒星时（LST）的函数，使用夜间数据和两个参数的拟合方程。忽略电离层影响，在0 ~ 12 h LST之间，$-2.59<\beta<-2.54 \pm 0.011$。当银河系中心位于天空中时，光谱指数为0.011，在18.2 h时达到$\beta =-2.46\pm 0. 011 $。除了7 ~ 12 h的LST范围外，观测结果稳定，夜间重现性<0.004$。我们将我们的测量结果与来自各种全球天空模型的预测进行比较，发现最接近的匹配是来自Guzm{\'a}n和Haslam天空地图的光谱指数，类似于EDGES高波段仪器在90-190 MHz的结果。还评估了三参数拟合，结果是光谱指数变得更加负$\sim$0.02，最大总不确定度为0.016。我们还发现，第三个参数，谱指数曲率，$\gamma$，被限制为$-0.11<\gamma<-0.04 $。校正夜间电离层吸收的预期水平会导致$\beta$变得更负$0.008$ - $0.016$，具体取决于LST。
We report the spectral index of diffuse radio emission between 50 and 100 MHz from data collected with two implementations of the Experiment to Detect the Global EoR Signature (EDGES) low-band system. EDGES employs a wide beam zenith-pointing dipole antenna centred on a declination of $-26.7^\circ$. We measure the sky brightness temperature as a function of frequency averaged over the EDGES beam from 244 nights of data acquired between 14 September 2016 to 27 August 2017. We derive the spectral index, $\beta$, as a function of local sidereal time (LST) using night-time data and a two-parameter fitting equation. We find $-2.59<\beta<-2.54 \pm 0.011$ between 0 and 12 h LST, ignoring ionospheric effects. When the Galactic Centre is in the sky, the spectral index flattens, reaching $\beta = -2.46 \pm 0.011$ at 18.2 h. The measurements are stable throughout the observations with night-to-night reproducibility of $\sigma_{\beta}<0.004$ except for the LST range of 7 to 12 h. We compare our measurements with predictions from various global sky models and find that the closest match is with the spectral index derived from the Guzm{\'a}n and Haslam sky maps, similar to the results found with the EDGES high-band instrument for 90-190 MHz. Three-parameter fitting was also evaluated with the result that the spectral index becomes more negative by $\sim$0.02 and has a maximum total uncertainty of 0.016. We also find that the third parameter, the spectral index curvature, $\gamma$, is constrained to $-0.11<\gamma<-0.04$. Correcting for expected levels of night-time ionospheric absorption causes $\beta$ to become more negative by $0.008$ - $0.016$ depending on LST.
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DOI：
10.3847/0004-637x/825/1/9
发表时间：
2016-03
期刊：
The Astrophysical Journal
影响因子：
--
作者：
N. Thyagarajan;A. Parsons;D. DeBoer;J. Bowman;A. Ewall-Wice;A. Neben;Nipanjana Patra
通讯作者：
N. Thyagarajan;A. Parsons;D. DeBoer;J. Bowman;A. Ewall-Wice;A. Neben;Nipanjana Patra
勘误表：—PAPER-64 对再电离的约束：z = 8.4 处的 21 cm 功率谱—(2015, ApJ, 809, 61)
DOI：
10.3847/1538-4357/aad7b4
发表时间：
2018
期刊：
The Astrophysical Journal
影响因子：
--
作者：
Ali, Zaki S.;Parsons, Aaron R.;Zheng, Haoxuan;Pober, Jonathan C.;Liu, Adrian;Aguirre, James E.;Bradley, Richard F.;Bernardi, Gianni;Carilli, Chris L.;Cheng, Carina
通讯作者：
Cheng, Carina
表征 21 cm 再电离功率谱中的信号损失：PAPER-64 的修订研究
DOI：
10.3847/1538-4357/aae833
发表时间：
2018
期刊：
The Astrophysical Journal
影响因子：
--
作者：
Cheng, Carina;Parsons, Aaron R.;Kolopanis, Matthew;Jacobs, Daniel C.;Liu, Adrian;Kohn, Saul A.;Aguirre, James E.;Pober, Jonathan C.;Ali, Zaki S.;Bernardi, Gianni
通讯作者：
Bernardi, Gianni
DOI：
10.1088/1538-3873/129/974/045001
发表时间：
2017-04-01
影响因子：
3.5
作者：
DeBoer, David R.;Parsons, Aaron R.;Zheng, Haoxuan
通讯作者：
Zheng, Haoxuan