An 850-μm SCUBA map of the Groth Strip and reliable source extraction
An 850-μm SCUBA map of the Groth Strip and reliable source extraction
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Groth Strip 的 850 μm SCUBA 地图和可靠的源提取
DOI：
10.1111/j.1365-2966.2005.08723.x
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发表时间：
2004
影响因子：
4.8
通讯作者：
S. Chapman
中科院分区：
文献类型：
--
作者：
K. Coppin;M. Halpern;D. Scott;C. Borys;S. Chapman
我们提出了一个850 μm的地图和候选源的列表中的一个分区的Groth带使用亚毫米通用测辐射热仪阵列（SCUBA）观察。这幅地图由一长串相邻的抖动地图组成，覆盖了原宽视场行星照相机2号成长带西南70弧分2的范围，平均1σ rms噪声水平为1.35 mJy。我们最初检测到7个候选源的信噪比在3.0和3.5σ之间，4个候选源的信噪比≥3.5。模拟表明，平均而言，在这种大小的地图中，预计有1.6个假阳性源≥3.5σ，在3和3.5σ之间有4.5个假阳性源。地图中的通量提升是一个众所周知的效果，我们已经开发了一个简单的贝叶斯公式来估计未提升的通量分布，并使用这种方法来确定我们的源的最佳通量估计。这种方法很容易适用于任何其他适度的信号-噪声调查，其中有源计数的先验知识。我们进行了后续测光，试图确认或拒绝我们的来源候选人。我们未能在地图上最嘈杂的区域显著地重新检测五个源中的三个，这表明它们要么是虚假的，要么具有接近噪声水平的真实通量。然而，我们确实确认了两个SCUBA源的真实性，尽管其流量水平低于地图中的建议。毫不奇怪，我们发现测光结果是一致的，并确认去增强地图通量。我们的最终候选源列表包含三个源，包括两个确认的检测和一个信噪比>3.5σ的另外的候选源，其具有真实的的合理机会。我们进行了相关性分析，并发现了XMM-Newton X射线源位置处正通量的证据。这些X射线源的平均通量密度的95%下限为0.8毫焦耳。
We present an 850-μm map and list of candidate sources in a subarea of the Groth Strip observed using the Submillimetre Common-User Bolometer Array (SCUBA). The map consists of a long strip of adjoining jiggle-maps covering the southwestern 70 arcmin2 of the original Wide Field Planetary Camera 2 Groth Strip to an average 1σ rms noise level of ≃3.5 mJy. We initially detect seven candidate sources with signal-to-noise ratios between 3.0 and 3.5σ and four candidate sources with signal-to-noise ratio ≥3.5. Simulations suggest that on average in a map this size one expects 1.6 false positive sources ≥3.5σ and 4.5 between 3 and 3.5σ. Flux boosting in maps is a well-known effect and we have developed a simple Bayesian prescription for estimating the unboosted flux distribution and used this method to determine the best flux estimates of our sources. This method is easily adapted for any other modest signal-to-noise survey in which there is prior knowledge of the source counts. We performed follow-up photometry in an attempt to confirm or reject five of our source candidates. We failed to significantly redetect three of the five sources in the noisiest regions of the map, suggesting that they are either spurious or have true fluxes close to the noise level. However, we did confirm the reality of two of the SCUBA sources, although at lower flux levels than suggested in the map. Not surprisingly, we find that the photometry results are consistent with and confirm the de-boosted map fluxes. Our final candidate source list contains three sources, including the two confirmed detections and one further candidate source with signal-to-noise ratio >3.5σ which has a reasonable chance of being real. We performed correlations and found evidence of positive flux at the positions of XMM–Newton X-ray sources. The 95 per cent lower limit for the average flux density of these X-ray sources is 0.8 mJy.