H i Observations of Major-merger Pairs at z = 0: Atomic Gas and Star Formation
H i Observations of Major-merger Pairs at z = 0: Atomic Gas and Star Formation
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DOI：
10.3847/1538-4365/aabd30
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发表时间：
2018-04
期刊：
影响因子：
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通讯作者：
P. Zuo;Cong K. Xu;M. Yun;U. Lisenfeld;Di Li;C. Cao
中科院分区：
文献类型：
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作者：
P. Zuo;Cong K. Xu;M. Yun;U. Lisenfeld;Di Li;C. Cao
我们提出了一项研究，研究了赫歇尔观测到的88个近主并合星系对（H- kpair）的大k波段选择样本的H气体含量。利用格林班克望远镜（Green Bank Telescope， GBT）对其中的58对进行了观测，并从文献中检索了另外12对的H i数据，获得了70对样品的21 cm H i精细结构发射在线数据。在这个H样本中，34对是螺旋-螺旋（S+S）对，36对是螺旋-椭圆（S+E）对。基于这些数据，我们研究了H -恒星质量比、H -气体分数和H -恒星形成效率（SFEH i =恒星形成率/MH i），并寻找S+S和S+E对之间的差异，以及有无合并/相互作用迹象的对之间的差异。我们的结果表明，这些对中螺旋星系的平均H -恒星质量比为=7.6±1.0%，与一般螺旋星系的平均H -气体分数一致。S+S对和S+E对的螺旋之间，以及有无合并/相互作用迹象的螺旋对之间的H气体分数差异不显著（<1σ）。另一方面，S+S对的平均SFEH i比S+E对高~ 4.6倍。这种差异非常显著（~ 4σ），是我们研究的主要结果。在有和没有合并/相互作用迹象的星系之间，平均SFEH i没有显著差异。整个样品的平均SFEH i为10−9.55±0.09 yr−1，对应的H消耗时间为3.5±0.7 Gyr。
We present a study of the H i gas content of a large K-band-selected sample of 88 close major-merger pairs of galaxies (H-KPAIR) that were observed by Herschel. We obtained the 21 cm H i fine-structure emission-line data for a total of 70 pairs from this sample, by observing 58 pairs using the Green Bank Telescope (GBT) and retrieving the H i data for an addition 12 pairs from the literature. In this H i sample, 34 pairs are spiral–spiral (S+S) pairs, and 36 are spiral–elliptical (S+E) pairs. Based on these data, we studied the H i-to-stellar mass ratio, the H i gas fraction, and the H i star formation efficiency (SFEH i = star-formation-rate/MH i) and searched for differences between S+S and S+E pairs, as well as between pairs with and without signs of merger/interaction. Our results showed that the mean H i-to-stellar mass ratio of spirals in these pairs is =7.6 ± 1.0%, consistent with the average H i gas fraction of spiral galaxies in general. The differences in the H i gas fraction between spirals in S+S and in S+E pairs, and between spirals in pairs with and without signs of merger/interaction, are insignificant (<1σ). On the other hand, the mean SFEH i of S+S pairs is ∼4.6× higher than that of S+E pairs. This difference is very significant (∼4σ) and is the main result of our study. There is no significant difference in the mean SFEH i between galaxies with and without signs of merger/interaction. The mean SFEH i of the whole pair sample is 10−9.55±0.09 yr−1, corresponding to a H i consumption time of 3.5 ± 0.7 Gyr.