2018/04/11 by Pei Zuo, Cong K. Xu, Min S. Yun +3 · 25 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Fraction (chemistry) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Mass fraction #Significant difference #Spiral galaxy #Star formation #astro-ph.GA
paper · pdf · doi:10.3847/1538-4365/aabd30
published in The Astrophysical Journal Supplement Series 237(1), 2 (Institute of Physics) · 12 pages, 8 figures, accepted for publication in ApJS. Note: not all the figures of Figure 1 and Figure B1 are included due to space limit of arXiv. People who are interested can contact us
arxiv created 2018/04/11 · openalex created_date 2018/04/24 · openalex publication_date 2018/07/01 · arxiv updated 2018/07/18 · openalex updated_date 2026/08/05
Abstract 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 (SFE H i = star-formation-rate/ M H 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 (<1 σ ). On the other hand, the mean SFE H i of S+S pairs is ∼4.6× higher than that of S+E pairs. This difference is very significant (∼4 σ ) and is the main result of our study. There is no significant difference in the mean SFE H i between galaxies with and without signs of merger/interaction. The mean SFE H 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.