Faint-Source Counts from Off-Source Fluctuation Analysis on Chandra Observations of the Hubble Deep Field-North
Faint-Source Counts from Off-Source Fluctuation Analysis on Chandra Observations of the Hubble Deep Field-North
复制标题
哈勃深场北区钱德拉观测的离源涨落分析的微弱源计数
DOI：
10.1086/338794
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
R. Griffiths
中科院分区：
文献类型：
--
作者：
T. Miyaji;R. Griffiths
我们报道了对哈勃深场北(HDF-N)100万秒钱德拉观测的离源场的涨落分析结果。细胞内计数的分布与对数N-对数S模型的预期进行了比较，以将源数密度的行为限制在比源检测下限低几倍的范围内。我们的结果表明，软带(0.5keV-2keV)的计数继续下降到Sx~7×10~(-18)ergs S~(-1)cm~(-2)，这可能意味着一个新的星系群的出现，这与Ptak等人关于恒星形成星系的预测是一致的。涨落分析可以松散地约束比探测下限更弱的源数，我们发现在硬带(2-10keV)的Sx~2×10-16ergs S-1 cm-2处有一个≲10,000源数的上限。
We report the results of fluctuation analysis of the off-source field from the 1 million second Chandra observation of the Hubble Deep Field-North (HDF-N). The distribution of the counts in cells has been compared with the expectations from the log N-log S model to constrain the behavior of the source number density down to a factor of several lower than the source detection limit. Our results show that the number counts in the soft band (0.5-2 keV) continue to grow down to SX ~ 7 × 10-18 ergs s-1 cm-2, possibly suggesting the emergence of a new population, and agree well with a prediction of star-forming galaxies by Ptak et al. The fluctuation analysis can loosely constrain the source counts fainter than the detection limit, and we found an upper limit of ≲10,000 sources deg-2 at SX ~ 2 × 10-16 ergs s-1 cm-2 in the hard (2-10 keV) band.