Properties of Molecular Gas in Galaxies in Early and Mid Stages of Interaction. III. Resolved Kennicutt-Schmidt Law

Abstract

We study properties of the interstellar medium, an ingredient of stars, and star formation activity, in four nearby galaxy pairs in the early and mid stages of interaction for both a galaxy scale and a kpc scale. The galaxy-scale Kennicutt-Schmidt law shows that seven of eight interacting galaxies have a star formation rate within a factor of three compared with the best-fit of the isolated galaxies, although we have shown that molecular hydrogen gas is efficiently produced from atomic hydrogen during the interaction in the previous paper. The galaxy-scale specific star formation rate (sSFR) and star formation efficiency (SFE) in interacting galaxies are comparable to those in isolated galaxies. We also investigate SFE and the Kennicutt-Schmidt law on a kpc scale. The spatial distributions of SFE reveal that SFE is locally enhanced, and the enhanced regions take place asymmetrically or at off-centre regions. The local enhancement of SFE could be induced by shock. We find that the index of the Kennicutt-Schmidt law for the interacting galaxies in the early stage is 1.30$\pm$0.04, which is consistent with that of the isolated galaxies. Since CO emission, which is used in the Kennicutt-Schmidt law, is a tracer of the amount of molecular gas, this fact suggests that dense gas, which is more directly connected to star formation, is not changed at the early stage of interaction.

40 pages, 15 figures, 10 tables; accepted for publication in PASJ

References in corpus (17)

• The GALEX Ultraviolet Atlas of Nearby Galaxies
• The effect of galaxy mass ratio on merger--driven starbursts
• Star formation efficiency in galaxy interactions and mergers: a statistical study
• An H-alpha Imaging Survey of Galaxies in the Local 11 Mpc Volume
• COLD GASS, an IRAM Legacy Survey of Molecular Gas in Massive Galaxies: II. The non-universality of the Molecular Gas Depletion Timescale
• The impact of interactions, bars, bulges, and AGN on star formation efficiency in local massive galaxies
• Minor Galaxy Interactions: Star Formation Rates and Galaxy Properties
• Interaction-induced star formation in a complete sample of 10^5 nearby star-forming galaxies
• The Spitzer Spirals, Bridges, and Tails Interacting Galaxy Survey: Interaction-Induced Star Formation in the Mid-Infrared
• Star formation efficiency in the Barred Spiral Galaxy NGC 4303
• CO Multi-line Imaging of Nearby Galaxies (COMING). IX. ${}^{12}$CO($J$=2-1)/${}^{12}$CO($J$=1-0) line ratio on kiloparsec scales
• ALMA Multi-line Observations of the IR-bright Merger VV 114
• The Mice at play in the CALIFA survey: A case study of a gas-rich major merger between first passage and coalescence
• Gas and Dust in the Taffy Galaxies: Ugc12914/15
• Wide-field 12CO (J = 1-0) Imaging of the Nearby Barred Galaxy M83 with NMA and Nobeyema 45-m telescope: Molecular Gas Kinematics and Star Formation Along the Bar
• A large amount of diffuse molecular gases in the bar of the strongly barred galaxy NGC1300: Cause of the low star formation efficiency
• Investigating the Relation between CO (3-2) and Far Infrared Luminosities for Nearby Merging Galaxies Using ASTE

Cited by in corpus (2)

• Exploring the Impact of Galactic Interactions and Mergers on the Central Star Formation of APEX/EDGE-CALIFA Galaxies
• Investigating physical states of molecular gas in the overlapping region of interacting galaxies NGC4567/4568 using ALMA