arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0808.2129astro-ph
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亚毫米星系有红移截止点吗?

Is there a redshift cutoff for submillimetre galaxies?

G. Raymond, S. A. Eales, S. Dye, R. Carlberg, M. Sullivan

摘要:

我们提出了新的光学和红外测光的统计完整的样品7个1.1毫米选定的来源与准确的亚毫米阵列坐标。我们确定的光度红移为4.47,4.50,1.49和0.64的七个来源。在其他三个源中,有两个源的光学波长低于斯巴鲁和加拿大-法国-夏威夷望远镜图像的极限($\sim$ 27等AB,i波段),其余源的测光被附近明亮的星系破坏。具有最高红移的源的红移比从最近最大的850 $μ$ m巡天中获取的$\sim$ 200个源中的除一个之外的所有源都高,这可能表明1.1 mm巡天比850 $μ$ m巡天在寻找非常高红移的源方面更有效。我们使用带状$V_{e}/V_{a}$分析研究了样品的数密度随红移的演化,没有发现红移截止的证据,尽管源的数量非常少。我们还进行了同样的分析,在850 $μ$米从GOODS-N场选择的38个星系的统计上完整的样本,并找到了下降的数量密度超过$z\sim1$和2热,冷尘埃为主的SMG分别的证据,证实了早期的结论墙,教皇和斯科特。我们还发现了强有力的证据,存在两个不同的发展子种群分离的光度,具有较高的相对密度的高光度星系在较高的红移。

英文摘要:

We present new optical and infrared photometry for a statistically complete sample of seven 1.1 mm selected sources with accurate Submillimetre Array coordinates. We determine photometric redshifts for four of the seven sources of 4.47, 4.50, 1.49 and 0.64. Of the other three sources two are undetected at optical wavelengths down to the limits of very deep Subaru and Canada-France-Hawaii Telescope images ($\sim$27 mag AB, i band) and the photometry of the remaining source is corrupted by a bright nearby galaxy. The sources with the highest redshifts are at higher redshifts than all but one of the $\sim$200 sources taken from the largest recent 850 $μ$m surveys, which may indicate that 1.1 mm surveys are more efficient at finding sources at very high redshifts than 850 $μ$m surveys. We investigate the evolution of the number density with redshift of our sample using a banded $V_{e}/V_{a}$ analysis and find no evidence for a redshift cutoff, although the number of sources is very small. We also perform the same analysis on a statistically complete sample of 38 galaxies selected at 850$μ$m from the GOODS-N field and find evidence for a drop-off in the number density beyond $z\sim1$ and 2 for hot and cold dust dominated SMGs respectively, confirming the earlier conclusion of Wall, Pope & Scott. We also find strong evidence for the existence of two differently evolving sub-populations separated in luminosity, with a higher relative density of the high luminosity galaxies at higher redshifts.

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