HERACLES：HERA共线河外巡天
HERACLES: The HERA CO-Line Extragalactic Survey
摘要：
我们提出了HERA CO线河外星系巡天（HERALES），这是来自18个附近星系的CO发射的图集，也是HI邻近星系巡天（THINGS）和斯皮策红外邻近星系巡天（SINGS）的一部分。我们使用IRAM 30-m望远镜上的HERA多像素接收器，以13”角分辨率和2.6 km/s的速度分辨率，在每个目标的整个光盘（由等照度半径r_25定义）上映射CO J=2-1线。在这里，我们描述的意见和减少的数据，并显示通道地图，方位角平均配置文件，集成的强度地图，峰值强度地图。隐含的H2质量范围从7 \times 10^6到6 \times 10^9 M_sun，有四个低金属丰度矮不规则星系只给出了上限。在检测到CO的情况下，H2与HI的综合比值范围为0.02 - 1.13，H2与恒星质量的比值范围为0.01 - 0.25。我们的目标的CO排放的指数尺度长度在0.8 - 3.2千秒差距的范围内，或0.2 \pm 0.05 r_25。CO的强度加权平均速度与HI的强度加权平均速度匹配得很好，1σ散射仅为6 km/s。CO J=2-1 / J=1-0的线比变化范围与银河系和其他附近星系相似，\sim 0.6 - 1.0，在星系中心发现更高的值。典型的谱线比\sim 0.8可以由激发温度为\sim 10 K的光学厚气体产生。
英文摘要：
We present the HERA CO-Line Extragalactic Survey (HERACLES), an atlas of CO emission from 18 nearby galaxies that are also part of The HI Nearby Galaxy Survey (THINGS) and the Spitzer Infrared Nearby Galaxies Survey (SINGS). We used the HERA multi-pixel receiver on the IRAM 30-m telescope to map the CO J=2-1 line over the full optical disk (defined by the isophotal radius r_25) of each target, at 13" angular resolution and 2.6 km/s velocity resolution. Here we describe the observations and reduction of the data and show channel maps, azimuthally averaged profiles, integrated intensity maps, and peak intensity maps. The implied H2 masses range from 7 \times 10^6 to 6 \times 10^9 M_sun, with four low metallicity dwarf irregular galaxies yielding only upper limits. In the cases where CO is detected, the integrated H2-to-HI ratios range from 0.02 - 1.13 and H2-to-stellar mass ratios from 0.01 to 0.25. Exponential scale lengths of the CO emission for our targets are in the range 0.8 - 3.2 kpc, or 0.2 \pm 0.05 r_25. The intensity-weighted mean velocity of CO matches that of HI very well, with a 1σscatter of only 6 km/s. The CO J=2-1 / J=1-0 line ratio varies over a range similar to that found in the Milky Way and other nearby galaxies, \sim 0.6 - 1.0, with higher values found in the centers of galaxies. The typical line ratio, \sim 0.8, could be produced by optically thick gas with an excitation temperature of \sim 10 K.
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