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arXiv 0806.4930astro-ph
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半导体的SDSS DR6光度函数

The SDSS DR6 Luminosity Functions of Galaxies

Antonio D. Montero-Dorta, Francisco Prada

摘要:

我们目前的数字计数,光度函数(LF)和光度密度的星系获得使用斯隆数字巡天第六次数据发布在所有SDSS光度带。多亏了SDSS DR 6,相对于Blanton等人(2003 b)以前的工作,星系统计在u波段增加了约9倍,在SDSS的其他波段增加了约4-5倍。此外,我们已经在我们的星系样本中实现了很高的红移完整性。首先,通过使用NYU-VAGC DR 6提供的巡天掩模,我们已经能够在天空中定义一个具有高角红移完整性的区域。其次,我们保证亮度相关的红移不完整性是小的幅度范围内,定义我们的星系样本。有了这些进展,我们已经在亮端和暗端都非常准确地估计了SDSS DR 6 LF。在{0.1}^r波段,我们的SDSS DR 6光度函数与Schechter LF很好地拟合,参数Phi_{*} =0.90 +/- 0.07$,M_{*}-5 log_{10} h=-20.73 +/- 0.04和alpha=-1.23 +/- 0.02。与以前的结果相比,我们发现了一些显着的差异。在{0.1}^u带光度函数的亮端,我们发现相对于最佳拟合的Schechter LF,在M_{{0.1}^u}=-20.5处有一个显著的过量,约为1.7 dex。这种过量在{0.1}^g波段中减弱,朝着非常红的{0.1}^z波段逐渐消失。对这个亮端隆起的性质的初步分析表明,它主要由活动星系和类星体组成。因此,这种超高亮度的一个重要部分可能来自核活动。在SDSS DR 6光度函数的暗端,我们可以达到比以前的SDSS LF估计深1-1.5个星等,我们获得了更陡的斜率[ABRIDGED]。

英文摘要:

We present number counts, luminosity functions (LFs) and luminosity densities of galaxies obtained using the Sloan Digital Sky Survey Sixth Data Release in all SDSS photometric bands. Thanks to the SDSS DR6, galaxy statistics have increased by a factor of ~9 in the u-band and by a factor of ~4-5 in the rest of the SDSS bands with respect to the previous work of Blanton et al. (2003b). In addition, we have achieved a high redshift completeness in our galaxy samples. Firstly, by making use of the survey masks, provided by the NYU-VAGC DR6, we have been able to define an area on the sky of high angular redshift completeness. Secondly, we guarantee that brightness-dependent redshift incompleteness is small within the magnitude ranges that define our galaxy samples. With these advances, we have estimated very accurate SDSS DR6 LFs in both the bright and the faint end. In the {0.1}^r-band, our SDSS DR6 luminosity function is well fitted by a Schechter LF with parameters Phi_{*}=0.90 +/- 0.07$, M_{*}-5log_{10}h=-20.73 +/- 0.04 and alpha=-1.23 +/- 0.02. As compared with previous results, we find some notable differences. In the bright end of the {0.1}^u-band luminosity function we find a remarkable excess, of ~1.7 dex at M_{{0.1}^u}=-20.5, with respect to the best-fit Schechter LF. This excess weakens in the {0.1}^g-band, fading away towards the very red {0.1}^z-band. A preliminary analysis on the nature of this bright-end bump reveals that it is mostly comprised of active galaxies and QSOs. It seems, therefore, that an important fraction of this exceeding luminosity may come from nuclear activity. In the faint end of the SDSS DR6 luminosity functions, where we can reach 1-1.5 magnitudes deeper than the previous SDSS LF estimation, we obtain a steeper slope [ABRIDGED].

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