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arXiv 0906.0981astro-ph.COastro-ph.IM
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从BLAST图的统计分析得到亚毫米波计数

Submillimeter Number Counts From Statistical Analysis of BLAST Maps

Guillaume Patanchon, Peter A. R. Ade, James J. Bock, Edward L. Chapin, Mark J. Devlin, Simon R. Dicker, Matthew Griffin, Joshua O. Gundersen, Mark Halpern, Pete… 展开作者

Guillaume Patanchon, Peter A. R. Ade, James J. Bock, Edward L. Chapin, Mark J. Devlin, Simon R. Dicker, Matthew Griffin, Joshua O. Gundersen, Mark Halpern, Peter C. Hargrave, David H. Hughes, Jeff Klein, Gaelen Marsden, Philip Mauskopf, Lorenzo Moncelsi, Calvin B. Netterfield, Luca Olmi, Enzo Pascale, Marie Rex, Douglas Scott, Christopher Semisch, Nicholas Thomas, Matthew D. P. Truch, Carole Tucker, Gregory S. Tucker, Marco P. Viero, Donald V. Wiebe

摘要:

我们描述了一种统计方法的应用,以估计亚毫米星系的数量计数从混乱有限的意见,由机载大口径亚毫米望远镜(BLAST)。我们的方法是基于极大似然拟合的像素直方图,有时被称为“P(D)”,一种方法,已被用来探测微弱的计数,不同的是,在这里,我们主张使用它,即使是相对较高的信噪比的来源。该方法具有优于源提取的标准技术的优点,在提供从亮端到远低于混淆极限的通量密度的计数的无偏估计。我们具体分析了大约10平方英尺的BLAST观测。°的地图以大天文台起源深层巡天南部(GOODS-S)场为中心。我们提供的估计数计数在三个BLAST波长,250,350,和500微米,而不是计数源的通量箱,我们估计的计数在几个通量密度节点与幂律。我们观察到在250微米处约为-3.7的计数和在350和500微米处约为-4.5的计数在约0.02-0.5 Jy的范围内通常非常陡峭的斜率,在所有三个波长处都在约0.015 Jy以下变为较浅的斜率。我们还描述了如何估计的不确定性和相关性,在这种方法,使其结果可以用于模型拟合。这种方法应该非常适合于分析Herschel卫星的数据。

英文摘要:

We describe the application of a statistical method to estimate submillimeter galaxy number counts from confusion limited observations by the Balloon-borne Large Aperture Submillimeter Telescope (BLAST). Our method is based on a maximum likelihood fit to the pixel histogram, sometimes called 'P(D)', an approach which has been used before to probe faint counts, the difference being that here we advocate its use even for sources with relatively high signal-to-noise ratios. This method has an advantage over standard techniques of source extraction in providing an unbiased estimate of the counts from the bright end down to flux densities well below the confusion limit. We specifically analyse BLAST observations of a roughly 10 sq. deg. map centered on the Great Observatories Origins Deep Survey South (GOODS-S) field. We provide estimates of number counts at the three BLAST wavelengths, 250, 350, and 500 microns; instead of counting sources in flux bins we estimate the counts at several flux density nodes connected with power-laws. We observe a generally very steep slope for the counts of about -3.7 at 250 microns and -4.5 at 350 and 500 microns, over the range ~0.02-0.5 Jy, breaking to a shallower slope below about 0.015 Jy at all three wavelengths. We also describe how to estimate the uncertainties and correlations in this method so that the results can be used for model-fitting. This method should be well-suited for analysis of data from the Herschel satellite.

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