Planetary nebulae in the UWISH2 survey
Planetary nebulae in the UWISH2 survey
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DOI：
10.1093/mnras/sty1580
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发表时间：
2018-06
影响因子：
4.8
通讯作者：
T. Gledhill;D. Froebrich;J. Campbell-White;A. Jones
中科院分区：
文献类型：
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作者：
T. Gledhill;D. Froebrich;J. Campbell-White;A. Jones
近红外成像在1？0 S（1）发射线能够探测行星状星云（PNe），而行星状星云在光学发射线测量中是不可见的。我们目前的图像的307个对象从UWISH 2调查的北方银道面，并与援助的中红外颜色诊断制定了一份名单，291 PN候选人。大多数，183，是新的检测和85%，这些都不存在于H？该地区的调查。我们发现，超过一半（54%）的对象有一个双极形态和一些对象以前被认为是椭圆形或点源H？成像，在UWISH 2图像中出现双极。通过考虑一个小的子集的对象的物理半径可从H？表面亮度半径的关系，我们发现的证据表明，H2表面亮度保持大致恒定的一个因素20范围内的半径从0.03至0.6 pc，包括大部分的可见光寿命的PN。这条路通向H？在大半径（> 0.5pc）下，表面亮度变得与H2相当。通过结合UWISH 2 PNe的数量没有H？检测与估计的PN检测效率在H2排放，我们估计，PN数从H？在UWISH 2调查区域内，调查可能低估真实PN数1.5至2.5倍。
Near-infrared imaging in the 1 ? 0 S(1) emission line of molecular hydrogen is able to detect planetary nebulae (PNe) that are hidden from optical emission line surveys. We present images of 307 objects from the UWISH2 survey of the northern Galactic Plane, and with the aid of mid-infrared colour diagnostics draw up a list of 291 PN candidates. The majority, 183, are new detections and 85 per cent of these are not present in H ? surveys of the region. We find that more than half (54 per cent) of objects have a bipolar morphology and that some objects previously considered as elliptical or point-source in H ? imaging, appear bipolar in UWISH2 images. By considering a small subset of objects for which physical radii are available from the H ? surface brightness-radius relation, we find evidence that the H2 surface brightness remains roughly constant over a factor 20 range of radii from 0.03 to 0.6 pc, encompassing most of the visible lifetime of a PN. This leads to the H ? surface brightness becoming comparable to that of H2 at large radius (>0.5 pc). By combining the number of UWISH2 PNe without H ? detection with an estimate of the PN detection efficiency in H2 emission, we estimate that PN numbers from H ? surveys may underestimate the true PN number by a factor between 1.5 and 2.5 within the UWISH2 survey area.