SIMBAD references

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 (<1σ). On the other hand, the mean SFE_H I_ of S+S pairs is ∼4.6x 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 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.