阿雷西博L波段馈源阵列回避区巡天I：通过星系内部和外部的前兆观测
The Arecibo L-band Feed Array Zone of Avoidance Survey I: Precursor Observations through the Inner and Outer Galaxy
摘要：
阿雷西博L波段馈源阵列正用于进行低银河纬度调查，通过探测星系21厘米中性氢发射，绘制星系分布图和银河系后面的大尺度结构。这个回避区（ZOA）的调查发现了隐藏在银河系后面的新的HI星系，并且还提供了在其他波长处已知的部分模糊星系的红移。在全面巡天开始之前，观测到两个低纬度前体区域，总面积为138平方度，探测到72个HI星系。由于严重的消光和恒星混乱，通过银河系内部的探测通常在任何其他波段都没有编目对应物。通过外星系的探测更有可能有2 MASS的对应物。我们提出了这些前兆观测的结果，包括检测到的星系的目录，其HI参数。调查的灵敏度是很好地描述了一个通量和线宽依赖的信噪比为6.5。ALFA ZOA星系，也有HI测量的文献中显示出良好的协议，我们的测量和以前的工作。银河系内部的前体区域被选择为与HI Parkes的回避区重叠，因此可以快速评估ALFA的性能。银河系前身的外围区域位于帕克斯天空的北部。揭示了该区域的低纬大尺度结构，包括在l = 183 °附近和5000 - 6000 km/s之间的ZOA中星系的过密度。完整的ALFA ZOA调查将分两个阶段进行：一个是使用前兆观测技术的浅层调查，另一个是具有更长积分时间的深层调查，最终目录预计有数千个星系。
英文摘要：
The Arecibo L-band Feed Array (ALFA) is being used to conduct a low-Galactic latitude survey, to map the distribution of galaxies and large-scale structures behind the Milky Way through detection of galaxies' neutral hydrogen (HI) 21-cm emission. This Zone of Avoidance (ZOA) survey finds new HI galaxies which lie hidden behind the Milky Way, and also provides redshifts for partially-obscured galaxies known at other wavelengths. Before the commencement of the full survey, two low-latitude precursor regions were observed, totalling 138 square degrees, with 72 HI galaxies detected. Detections through the inner Galaxy generally have no cataloged counterparts in any other waveband, due to the heavy extinction and stellar confusion. Detections through the outer Galaxy are more likely to have 2MASS counterparts. We present the results of these precursor observations, including a catalog of the detected galaxies, with their HI parameters. The survey sensitivity is well described by a flux- and linewidth-dependent signal-to-noise ratio of 6.5. ALFA ZOA galaxies which also have HI measurements in the literature show good agreement between our measurements and previous work. The inner Galaxy precursor region was chosen to overlap the HI Parkes Zone of Avoidance Survey so ALFA performance could be quickly assessed. The outer Galaxy precursor region lies north of the Parkes sky. Low-latitude large-scale structure in this region is revealed, including an overdensity of galaxies near l = 183 deg and between 5000 - 6000 km/s in the ZOA. The full ALFA ZOA survey will be conducted in two phases: a shallow survey using the observing techniques of the precursor observations, and also a deep phase with much longer integration time, with thousands of galaxies predicted for the final catalog.
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