Constraining the luminosity function of faint undetected i-dropout galaxies
Constraining the luminosity function of faint undetected i-dropout galaxies
复制标题
约束未检测到的微弱 i-dropout 星系的光度函数
DOI：
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
A. Koekemoer
中科院分区：
文献类型：
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作者：
V. Calvi;V. Calvi;A. Pizzella;A. Pizzella;M. Stiavelli;L. Morelli;L. Morelli;E. Corsini;E. Corsini;E. Bontà;E. Bontà;L. Bradley;A. Koekemoer
我们提出了一种新的技术来量化的光的贡献来自微弱的高红移（$z\sim6$）星系低于成像数据的检测阈值，设置传统的S/N=4.5。我们说明了技术与应用程序的哈勃空间望远镜先进相机的调查图像中的F775 W和F850 LP过滤器的超深场平行场NICP 12。这个分析的目的是将光度函数的暗端在$z\sim6$处扩展几个量级。在掩蔽了所有检测到的源之后，我们应用快速傅立叶变换来获得背景信号的空间功率谱。功率谱允许我们分离背景噪声信号，由于宽场数据减少的残差，以及微弱星系产生的整体信号。在i_775和z_850波段的信号的比率被用来估计微弱的i-dropout对象的贡献。我们依靠广泛的蒙特卡罗模拟来表征各种来源的不确定性和量化的数量暗淡的i-辍学星系在该领域。分析使我们能够将亮度函数的限制在z_850= 30等，比相同数据的标准技术暗2.5等。这些数据与光度函数的微弱末端斜率$\alpha =-1.9$一致。假设一组特定的值的聚集因子，逃逸分数，和光谱能量分布，我们发现，$z\sim6$未被检测到的星系下降到z_850=30等可以驱动宇宙再电离。
We present a new technique to quantify the light contribution coming from the faint high redshift ($z\sim6$) galaxies below the detection threshold of imaging data, set conventionally at S/N=4.5. We illustrate the technique with an application to Hubble Space Telescope Advanced Camera for Surveys images in the F775W and F850LP filters of the Ultra Deep Field parallel field NICP12. The aim of this analysis is to extend by a few magnitudes the faint end of the luminosity function at $z\sim6$. After masking all the detected sources in the field we apply a Fast Fourier Transform to obtain the spatial power spectrum of the background signal. The power spectrum permits us to separate the background noise signal, the residuals due to the data reduction of the wide field, and the overall signal produced by faint galaxies. The ratio of the signal in the i_775 and z_850 bands is used to estimate the contribution of the faint i-dropout objects. We rely on extensive Monte Carlo simulations to characterize various sources of uncertainty and quantify the number of faint i-dropout galaxies in the field. The analysis allows us to put constraints on the luminosity function at $z\sim6$ down to z_850= 30 mag, 2.5 mag fainter than with standard techniques on the same data. The data are consistent with a faint end slope of the luminosity function of $\alpha = -1.9$. Assuming a specific set of values for the clumping factor, escape fraction, and spectral energy distribution, we find that the $z\sim6$ undetected galaxies down to z_850=30 mag could have driven cosmic reionization.
影响因子：
8.7
作者：
Komatsu, E.;Smith, K. M.;Wright, E. L.
通讯作者：
Wright, E. L.