论文标题
试点搜索快速吸收外乳癌OH的吸收
A pilot search for extragalactic OH absorption with FAST
论文作者
论文摘要
OH吸收目前是在宇宙学距离下检测非量化星系中OH分子的唯一可行方法。迄今为止，在z> 0.05时只有6个这样的检测，因此很难对遥远星系中的OH列密度统计上有稳定的约束。我们使用五百米的光圈球形射程望远镜（FAST）对8个相关的HI 21-CM吸收剂进行了一次试点OH吸收调查。对于[0.1919，0.2241]中的红移z，我们能够将相对于HI（[OH]/[HI]）相对于HI（[OH]/[HI]）的OH丰度限制为低于10^-6〜10^-8。尽管没有进行单独检测，但没有RFI的三名相关吸收器提供了敏感的OH柱密度3- sigma上限〜1.57 x 10^14（tx/10k）（1/fc）cm^-2，对应于[oh]/[oh]/[hi]/[hi] <5.45 x 10^-8。与档案数据相结合，我们表明相关的吸收器的OH丰度比干预吸收器略低。我们的结果与随着红移的减少降低OH丰度的趋势是一致的。
OH absorption is currently the only viable way to detect OH molecules in non-masing galaxies at cosmological distances. There have been only 6 such detections at z>0.05 to date and so it is hard to put a statistically robust constraint on OH column densities in distant galaxies. We carried out a pilot OH absorption survey towards 8 associated and 1 intervening HI 21-cm absorbers using the Five-hundred-meter Aperture Spherical radio Telescope (FAST). We were able to constrain the OH abundance relative to HI ([OH]/[HI]) to be lower than 10^-6 ~ 10^-8 for redshifts z within [0.1919, 0.2241]. Although no individual detection was made, stacking three associated absorbers free of RFI provides a sensitive OH column density 3-sigma upper-limit ~ 1.57 x 10^14 (Tx/10K)(1/fc) cm^-2, which corresponds to a [OH]/[HI] < 5.45 x 10^-8. Combining with archival data, we show that associated absorbers have a slightly lower OH abundance than intervening absorbers. Our results are consistent with a trend of decreasing OH abundance with decreasing redshift.
