HI Gas and Star Formation in Major Galaxy Pairs from the FAST All-Sky HI Survey (FASHI)

Abstract

Atomic hydrogen (HI) plays a fundamental role in fueling star formation in galaxies. However, the behavior of HI gas in interacting systems, particularly galaxy pairs, remains elusive. In this work, we investigate the HI content of major mergers by cross-matching the extragalactic HI catalog from the FAST All-Sky HI Survey (FASHI) with a previously established sample of isolated galaxy pairs. With the superior sensitivity of FAST, we have constructed the largest sample of major mergers with HI detections, consisting of $440$ galaxy pairs: $364$ spiral-spiral (S+S) and $76$ spiral-elliptical (S+E) systems. We examine the HI gas fraction ($f_{\mathrm{HI}}$), star formation rate (SFR) and HI star formation efficiency ($\mathrm{SF}{\mathrm{E}}_{\mathrm{HI}}=\mathrm{SFR}/M_{\mathrm{HI}}$) for individual galaxies in pairs. The control sample is matched in both stellar mass and redshift. We find that paired galaxies, particularly those in pairs with small projected separations ($d_{\mathrm{p}}<50h^{-1}\mathrm{kpc}$), exhibit systematically lower (by $8.8\%$) HI gas fractions compared to the control galaxies. The SFR is enhanced for galaxies in S+S pairs. $\mathrm{SF}{\mathrm{E}}_{\mathrm{HI}}$ is $\sim 15\%$ higher for galaxies in S+S pairs than in the control galaxies, while spiral galaxies in S+E pairs show no significant difference in $\mathrm{SF}{\mathrm{E}}_{\mathrm{HI}}$ compared to the control sample. These findings suggest that the merging process triggers efficient HI gas depletion and enhances star formation, especially in close S+S pairs. Notably, our sample includes $26$ red spirals in paired systems. These galaxies exhibit HI deficiency and suppressed star formation activity compared to the isolated galaxies, indicating that interactions may affect quiescent spirals differently, potentially due to mechanisms similar to ellipticals.

14 pages, 9 figures, accepted by ApJ

References in corpus (28)

• Galaxy Zoo 1 : Data Release of Morphological Classifications for nearly 900,000 galaxies
• Cold gas accretion in galaxies
• GALEX-SDSS-WISE Legacy Catalog (GSWLC): Star Formation Rates, Stellar Masses and Dust Attenuations of 700,000 Low-redshift Galaxies
• The Fundamental Performance of FAST with 19-beam Receiver at L Band
• WALLABY -- An SKA Pathfinder HI Survey
• The Northern HIPASS catalogue - Data presentation, completeness and reliability measures
• Interacting galaxies on FIRE-2: The connection between enhanced star formation and interstellar gas content
• The main sequence of star forming galaxies I. The local relation and its bending
• Spatially resolved star formation and fuelling in galaxy interactions
• New HI scaling relations to probe the HI content of galaxies via global HI-deficiency maps
• xGASS: Gas-rich central galaxies in small groups and their connections to cosmic web gas feeding
• The FAST all sky HI survey (FASHI): The first release of catalog
• The baryonic specific angular momentum of disc galaxies
• xGASS: HI fueling of star formation in disk-dominated galaxies
• Galaxy Pairs in the Sloan Digital Sky Survey - X: Does gas content alter star formation rate enhancement in galaxy interactions?
• The neutral gas content of post-merger galaxies
• A tight angular-momentum plane for disc galaxies
• CO observations of major merger pairs at z=0: Molecular gas mass and star formation
• SDSS-IV MaNGA: Kinematic Asymmetry as An Indicator of Galaxy Interaction in Paired Galaxies
• Enhanced HI profile asymmetries in close galaxy pairs
• Towards an Understanding of the Massive Red Spiral Galaxy Formation
• On the HI Content of MaNGA Major Merger Pairs
• Interacting galaxies in the IllustrisTNG simulations -- V: Comparing the influence of star-forming vs. passive companions
• HI study of isolated and pair galaxies: the MIR SFR-M$\star$ sequence
• HI content of massive red spiral galaxies observed by FAST
• Massive Red Spiral Galaxies in SDSS-IV MaNGA Survey
• FEASTS Combined with Interferometry. III. The Low Column Density HI Around M51 and Possibility of Turbulent-mixing Gas Accretion
• CO Observations of Early-mid Stage Major Mergers in the MaNGA Survey