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arXiv 1206.0943astro-ph.CO
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星系和质量集合体(GAMA):来自校准光度红移的颜色和光度相关的成簇

Galaxy and Mass Assembly (GAMA): Colour and luminosity dependent clustering from calibrated photometric redshifts

L. Christodoulou, C. Eminian, J. Loveday, P. Norberg, I. K. Baldry, P. D. Hurley, S. P. Driver, S. P. Bamford, A. M. Hopkins, J. Liske, J. A. Peacock, J. Bland-… 展开作者

L. Christodoulou, C. Eminian, J. Loveday, P. Norberg, I. K. Baldry, P. D. Hurley, S. P. Driver, S. P. Bamford, A. M. Hopkins, J. Liske, J. A. Peacock, J. Bland-Hawthorn, S. Brough, E. Cameron, C. J. Conselice, S. M. Croom, C. S. Frenk, M. Gunawardhana, D. H. Jones, L. S. Kelvin, K. Kuijken, R. C. Nichol, H. Parkinson, K. A. Pimbblet, C. C. Popescu, M. Prescott, A. S. G. Robotham, R. G. Sharp, W. J. Sutherland, E. N. Taylor, D. Thomas, R. J. Tuffs, E. van Kampen, D. Wijesinghe

摘要:

我们测量了来自Sloan数字巡天的4,289,223个r < 19.4等的星系的两点角关联函数,作为光度红移、绝对星等和颜色的函数,直到M_r -5logh = -14等。光度红移是由ugriz模型星等和两个Petrosian半径用人工神经网络包ANNz估计的。利用星系和质量大会(GAMA)光谱样本作为我们的训练集。光度学的红移被用来确定绝对星等和颜色。对于我们所有的样本,我们估计潜在的红移和绝对星等分布,使用蒙特卡罗响应。这些红移分布被用于林伯方程中,以从幂律拟合到角关联函数来获得空间关联函数参数。我们证实,在小尺度下,在所有的红移仓中,与~L* 红星系相比,sub-L* 红星系的聚集强度增加,而对于蓝色种群,相关长度几乎与~L* 星系的光度无关,并且更暗。相对偏差与对数光度之间存在线性关系,线性范围为L~0.03L*。我们发现,L* 布居的偏置对红移的依赖关系可以用Tegmark & Peebles(1998)的被动演化模型来描述。对我们的r < 19.4的SDSS星系样本的随机样本进行目视检查,发现大约10%是虚假的,由于附近星系的过度去混,对非常微弱的绝对星等的污染率更高。我们在聚类分析中校正了这种污染。

英文摘要:

We measure the two-point angular correlation function of a sample of 4,289,223 galaxies with r < 19.4 mag from the Sloan Digital Sky Survey as a function of photometric redshift, absolute magnitude and colour down to M_r - 5log h = -14 mag. Photometric redshifts are estimated from ugriz model magnitudes and two Petrosian radii using the artificial neural network package ANNz, taking advantage of the Galaxy and Mass Assembly (GAMA) spectroscopic sample as our training set. The photometric redshifts are then used to determine absolute magnitudes and colours. For all our samples, we estimate the underlying redshift and absolute magnitude distributions using Monte-Carlo resampling. These redshift distributions are used in Limber's equation to obtain spatial correlation function parameters from power law fits to the angular correlation function. We confirm an increase in clustering strength for sub-L* red galaxies compared with ~L* red galaxies at small scales in all redshift bins, whereas for the blue population the correlation length is almost independent of luminosity for ~L* galaxies and fainter. A linear relation between relative bias and log luminosity is found to hold down to luminosities L~0.03L*. We find that the redshift dependence of the bias of the L* population can be described by the passive evolution model of Tegmark & Peebles (1998). A visual inspection of a random sample of our r < 19.4 sample of SDSS galaxies reveals that about 10 per cent are spurious, with a higher contamination rate towards very faint absolute magnitudes due to over-deblended nearby galaxies. We correct for this contamination in our clustering analysis.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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