Time-average properties of $z\sim 0.6$ major mergers: mergers significantly scatter high-z scaling relations

Abstract

Interpreting the scaling relations measured by recent large kinematic surveys of $z<1$ galaxies has remained hampered by large observational scatter. We show that the observed ISM and morpho-dynamical properties along the average $z\sim 0.6$ major merger describe a very self-consistent picture in which star formation is enhanced during first passage and fusion as a result of gravitational perturbations due to the interaction, while the gas velocity dispersion is simultaneously enhanced through shocks that convert kinematic energy associated with bulk orbital motions into turbulence at small scales. Angular momentum and rotation support in the disc are partly lost during the most perturbing phases, resulting in a morphologically compact phase. The fractions of present-day E/S0 versus later type galaxies can be predicted within only a few per cent, confirming that roughly half of local discs were reformed in the past 8-9 Gyr after gas-rich major mergers. Major mergers are shown to strongly scatter scaling relations involving kinematic quantities (e.g. the Tully-Fisher or Fall relations). Selecting high-z discs relying only on $V/\sigma$ turns out to be less efficient than selecting discs from multiple criteria based on their morpho-kinematic properties, which can reduce the scatter of high-z scaling relations down to the values measured in local galaxy samples.

18 pages, 7 figures, 2 tables; accepted for publication in MNRAS

References in corpus (43)

• 3D-HST+CANDELS: The Evolution of the Galaxy Size-Mass Distribution since $z=3$
• The KMOS^3D Survey: design, first results, and the evolution of galaxy kinematics from 0.7<z<2.7
• The effect of galaxy mass ratio on merger--driven starbursts
• Star formation efficiency in galaxy interactions and mergers: a statistical study
• Star formation in AEGIS field galaxies since z=1.1 . Staged galaxy formation, and a model of mass-dependent gas exhaustion
• Moving mesh cosmology: tracing cosmological gas accretion
• Dynamical Properties of z~2 Star Forming Galaxies and a Universal Star Formation Relation
• Ionized gas outflows and global kinematics of low-z luminous star forming galaxies
• The evolution of the near-IR galaxy Luminosity Function and colour bimodality up to z ~ 2 from the UKIDSS Ultra Deep Survey Early Data Release
• The SAMI Galaxy Survey: the link between angular momentum and optical morphology
• Why stellar feedback promotes disc formation in simulated galaxies
• IMAGES-III: The evolution of the Near-Infrared Tully-Fisher relation over the last 6 Gyr
• High-redshift major mergers weakly enhance star formation
• A consistent measure of the merger histories of massive galaxies using close-pair statistics I: Major mergers at $z<3.5$
• The KMOS Redshift One Spectroscopic Survey (KROSS): the origin of disk turbulence in z~0.9 star-forming galaxies
• The KMOS Redshift One Spectroscopic Survey (KROSS): rotational velocities and angular momentum of z~0.9 galaxies
• Massive Close Pairs Measure Rapid Galaxy Assembly in Mergers at High Redshift
• IMAGES I. Strong evolution of galaxy kinematics since z=1
• The H alpha Galaxy Survey. VIII. Close companions and interactions, and the definition of starbursts
• Major Merging History in CANDELS. I. Evolution of the Incidence of Massive Galaxy-Galaxy Pairs from z=3 to z~0
• High-Redshift Galaxy Kinematics: Constraints on Models of Disk Formation
• The spatially resolved star formation history of CALIFA galaxies: Cosmic time scales
• The MUSE Hubble Ultra Deep Field Survey. IX. Evolution of galaxy merger fraction since z~6
• Galaxy Mergers at z>1 in the HUDF: Evidence for a Peak in the Major Merger Rate of Massive Galaxies
• Structure Formation Inside Triaxial Dark Matter Halos: Galactic Disks, Bulges and Bars
• SAURON's Challenge for the Major Merger Scenario of Elliptical Galaxy Formation
• 3D Spectroscopy with VLT/GIRAFFE - IV: Angular Momentum and Dynamical Support of Intermediate Redshift Galaxies
• Morpho-kinematics of z~1 galaxies probe the hierarchical scenario
• A giant bar induced by a merger event at z=0.4?
• The ALHAMBRA survey: Accurate merger fractions by PDF analysis of photometric close pairs
• 3D spectroscopy with VLT/GIRAFFE - II: Are Luminous Compact Galaxies merger remnants ?
• The limited role of galaxy mergers in driving stellar mass growth over cosmic time
• A forming, dust enshrouded disk at z=0.43: the first example of a late type disk rebuilt after a major merger?
• The diverse formation histories of simulated disc galaxies
• Kinematic classifications of local interacting galaxies: implications for the merger/disk classifications at high-z
• Galactic angular momentum in cosmological zoom-in simulations. I. Disk and bulge components and the galaxy--halo connection
• A comparison of the morphological properties between local and z~1 infrared luminous galaxies. Are local and high-z (U)LIRGs different?
• A decrease of the gas exchanges between galaxies and the IGM, from 12 to 6 billion years ago
• A forming disk at z~0.6: Collapse of a gaseous disk or major merger remnant?
• Most pseudo-bulges can be formed at later stages of major mergers
• The main sequence of star-forming galaxies at z~0.6: reinstating major mergers
• The diversity of assembly histories leading to disc galaxy formation in a LambdaCDM model
• 3D spectroscopy with VLT/GIRAFFE - III: Mapping electron densities in distant galaxies

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