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首页> 外文期刊>The Astrophysical Journal. Supplement Series >CO(J = 1-0) imaging of M51 with CARMA and the Nobeyama 45 m telescope
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CO(J = 1-0) imaging of M51 with CARMA and the Nobeyama 45 m telescope

机译：用CARMA和Nobeyama 45 m望远镜对M51进行CO（J = 1-0）成像

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摘要

We report the CO(J = 1-0) observations of the Whirlpool Galaxy M51 using both the Combined Array for Research in Millimeter Astronomy (CARMA) and the Nobeyama 45 m telescope (NRO45). We describe a procedure for the combination of interferometer and single-dish data. In particular, we discuss (1) the joint imaging and deconvolution of heterogeneous data, (2) the weighting scheme based on the root-mean-square (rms) noise in the maps, (3) the sensitivity and uv coverage requirements, and (4) the flux recovery of a combined map. We generate visibilities from the single-dish map and calculate the noise of each visibility based on the rms noise. Our weighting scheme, though it is applied to discrete visibilities in this paper, should be applicable to grids in uv space, and this scheme may advance in future software development. For a realistic amount of observing time, the sensitivities of the NRO45 and CARMA visibility data sets are best matched by using the single-dish baselines only up to 4-6 kλ (about 1/4-1/3 of the dish diameter). The synthesized beam size is determined to conserve the flux between the synthesized beam and convolution beam. The superior uv coverage provided by the combination of CARMA long baseline data with 15 antennas and NRO45 short spacing data results in the high image fidelity, which is evidenced by the excellent overlap between even the faint CO emission and dust lanes in an optical Hubble Space Telescope image and polycyclicaromatichydrocarbon emission in a Spitzer 8 μm image. The total molecular gas masses of NGC 5194 and 5195 (d = 8.2 Mpc) are 4.9 × 10 ~9 M _⊙ and 7.8 × 10~7 M _⊙, respectively, assuming the CO-to-H_2 conversion factor of X _(CO) = 1.8 × 10~(20) cm~(-2)(K km s~(-1))~(-1). The presented images are an indication of the millimeter-wave images that will become standard in the next decade with CARMA and NRO45, and the Atacama Large Millimeter/Submillimeter Array.
机译：我们报告了毫米波天文学M51使用组合阵列研究毫米天文学（CARMA）和Nobeyama 45 m望远镜（NRO45）的惠而浦银河M51的CO（J = 1-0）观测。我们描述了干涉仪和单碟数据结合的程序。特别是，我们讨论（1）异构数据的联合成像和反卷积;（2）基于地图中均方根（rms）噪声的加权方案;（3）灵敏度和uv覆盖率要求;以及（4）通量恢复的组合图。我们从单碟地图生成可见性，并根据均方根噪声计算每个能见度的噪声。我们的加权方案虽然适用于离散可视性，但应该适用于uv空间中的网格，并且该方案可能会在将来的软件开发中有所发展。对于现实的观察时间，通过仅使用最大不超过4-6kλ（大约盘直径的1 / 4-1 / 3）的单盘基线，可以最佳地匹配NRO45和CARMA可见性数据集的灵敏度。确定合成光束的大小以保留合成光束和卷积光束之间的通量。 CARMA长基线数据与15根天线和NRO45短距离数据的结合提供了卓越的uv覆盖范围，从而实现了高图像保真度，这在光学哈勃太空望远镜中即使是微弱的CO发射与尘埃道之间也能很好地重叠图像和Spitzer 8μm图像中的多环芳烃排放量。假设CO到H_2的转换因子X _，NGC 5194和5195的总分子气体质量（d = 8.2 Mpc）分别为4.9×10〜9 M_⊙和7.8×10〜7 M_⊙。 CO）= 1.8×10〜（20）cm〜（-2）（K km s〜（-1））〜（-1）。所显示的图像表示毫米波图像的显示，这些图像将在未来十年中与CARMA和NRO45以及Atacama大毫米波/亚毫米波阵列一起成为标准图像。

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