Star Formation Suppresion by Tidal Removal of Cold Molecular Gas from an Intermediate-Redshift Massive Post-Starburst Galaxy

Abstract

Observations and simulations have demonstrated that star formation in galaxies must be actively suppressed to prevent the formation of over-massive galaxies. Galactic outflows driven by stellar feedback or supermassive black hole accretion are often invoked to regulate the amount of cold molecular gas available for future star formation, but may not be the only relevant quenching processes in all galaxies. We present the discovery of vast molecular tidal features extending up to 64 kpc outside of a massive z=0.646 post-starburst galaxy that recently concluded its primary star-forming episode. The tidal tails contain (1.2 +/- 0.1)x10^10 Msun of molecular gas, 47 +/- 5 % of the total cold gas reservoir of the system. Both the scale and magnitude of the molecular tidal features are unprecedented compared to all known nearby or high-redshift merging systems. We infer that the cold gas was stripped from the host galaxies during the merger, which is most likely responsible for triggering the initial burst phase and the subsequent suppression of star formation. While only a single example, this result shows that galaxy mergers can regulate the cold gas contents in distant galaxies by directly removing a large fraction of the molecular gas fuel, and plausibly suppress star formation directly, a qualitatively different physical mechanism than feedback-driven outflows.

Published in ApJL, 8 pages, 5 figures

References in corpus (15)

• 3D-HST+CANDELS: The Evolution of the Galaxy Size-Mass Distribution since $z=3$
• Simba: Cosmological Simulations with Black Hole Growth and Feedback
• The effect of galaxy mass ratio on merger--driven starbursts
• Observational constraints on the merger history of galaxies since $z\approx 6$: Probabilistic galaxy pair counts in the CANDELS fields
• The Structures of Distant Galaxies - III: The Merger History of over 20,000 Massive Galaxies at z < 1.2
• The evolution of post-starburst galaxies from z=2 to z= 0.5
• Galaxy Merger Rates up to z $\sim$ 3 using a Bayesian Deep Learning Model $-$ A Major-Merger classifier using IllustrisTNG Simulation data
• Massive quenched galaxies at z~0.7 retain large molecular gas reservoirs
• Stellar feedback as the origin of an extended molecular outflow in a starburst galaxy
• Evolution Through the Post-Starburst Phase: Using Post-Starburst Galaxies as Laboratories for Understanding the Processes that Drive Galaxy Evolution
• VCC 2062: an old Tidal Dwarf Galaxy in the Virgo Cluster?
• ALMA Observations of a Candidate Molecular Outflow in an Obscured Quasar
• The Role of Active Galactic Nuclei in the Quenching of Massive Galaxies in the SQuiGGLE Survey
• Molecular gas and dust in Arp 94: The formation of a recycled galaxy in an interacting system
• A titanic interstellar medium ejection from a massive starburst galaxy at redshift 1.4

Cited by in corpus (1)

• Extreme Tidal Stripping May Explain the Overmassive Black Hole in Leo I: a Proof of Concept