FINDING DISTANT GALACTIC H ii REGIONS
FINDING DISTANT GALACTIC H ii REGIONS
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DOI：
10.1088/0067-0049/221/2/26
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发表时间：
2015-10
期刊：
影响因子：
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通讯作者：
L. Anderson;W. Armentrout;B. Johnstone;T. Bania;D. Balser;T. Wenger;V. Cunningham
中科院分区：
文献类型：
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作者：
L. Anderson;W. Armentrout;B. Johnstone;T. Bania;D. Balser;T. Wenger;V. Cunningham
WISE星系H II区星表包含缺少电离气体光谱观测的∼2000H II区候选区域。所有候选者都具有WISE 12m？>；发射周围22m？>；发射的特征HⅡ区中红外形态，此外还探测到了射电连续发射。本文报道了绿岸望远镜氢射电复合线和射电连续谱在2 2 5°≥ℓ≥−2 0°，|b|≤6°区的3 0 2个候选H II区的X波段(9 GHz；3 cm)的探测结果。？>；在这里，我们扩展了我们的H II区域发现调查的天空覆盖范围，该调查现在包含了分布在整个北方天空的近800个H II区域。我们提供了302个探测器的LSR速度和其中131个探测器的运动距离。在这302个新发现的天体中，有5个的(ℓ，b，v)？和gt；坐标与银河系最远的分子螺旋臂--半人马座外臂一致。由于银河系的翘曲，这些星云是在银河系第一象限的银河系纬度<1°处发现的，因此在以前的银河系平面调查中没有发现。另外一个区域的经度和速度与OSC一致，但位于银河系的负纬度(G039.183−01.422；−54.9 KM S？OSC H II区的日心距离和银河中心距离分别为22kpc和16kpc，是银河系中已知的最远的区域。我们在ℓ≃附近发现了另外三个HⅡ区，它们的LSR速度使它们位于银河中心半径19kpc。如果它们的距离是正确的，这些星云可能代表了银河系大质量恒星形成的极限。
The WISE Catalog of Galactic H ii Regions contains ∼2000 H ii region candidates lacking ionized gas spectroscopic observations. All candidates have the characteristic H ii region mid-infrared morphology of WISE 12 m ?> emission surrounding 22 m ?> emission, and additionally have detected radio continuum emission. We here report Green Bank Telescope hydrogen radio recombination line and radio continuum detections in the X-band (9 GHz; 3 cm) of 302 WISE H ii region candidates (out of 324 targets observed) in the zone 225 ° ≥ ℓ ≥ − 20 ° ?> , ∣ b ∣ ≤ 6 ° . ?> Here we extend the sky coverage of our H ii region Discovery Survey, which now contains nearly 800 H ii regions distributed across the entire northern sky. We provide LSR velocities for the 302 detections and kinematic distances for 131 of these. Of the 302 new detections, 5 have ( ℓ , b , v ) ?> coordinates consistent with the Outer Scutum–Centaurus Arm (OSC), the most distant molecular spiral arm of the Milky Way. Due to the Galactic warp, these nebulae are found at Galactic latitudes >1° in the first Galactic quadrant, and therefore were missed in previous surveys of the Galactic plane. One additional region has a longitude and velocity consistent with the OSC but lies at a negative Galactic latitude (G039.183−01.422; −54.9 km s - 1 ?> ). With Heliocentric distances >22 kpc and Galactocentric distances >16 kpc, the OSC H ii regions are the most distant known in the Galaxy. We detect an additional three H ii regions near ℓ ≃ 150 ° ?> whose LSR velocities place them at Galactocentric radii >19 kpc. If their distances are correct, these nebulae may represent the limit to Galactic massive star formation.