The merger rates and sizes of galaxies across the peak epoch of star formation from the HiZELS survey

Abstract

We use the HiZELS narrow-band H-alpha survey in combination with CANDELS, UKIDSS and WIRDS near-infrared imaging, to investigate the morphologies, merger rates and sizes of a sample of H-alpha emitting galaxies in the redshift range z=0.40 - 2.23, an epoch encompassing the rise to the peak of the star formation rate density. Merger rates are estimated from space- and ground-based imaging using the M20 coefficient. To account for the increase in the specific star-formation rate (sSFR) of the star forming `main-sequence' with redshift, we normalise the star-formation rate of galaxies at each epoch to the typical value derived from the H-alpha luminosity function. Once this trend in sSFR is removed we see no evidence for an increase in the number density of star-forming galaxies or the merger rate with redshift. We thus conclude that neither is the main driver of the enhanced star-formation rate density at z=1-2, with secular processes such as instabilities within efficiently fuelled, gas-rich discs or multiple minor mergers the most likely alternatives. However, we find that 40-50% of starburst galaxies, those with enhanced specific star formation at their epoch, are major mergers and this fraction is redshift independent. Finally, we find the surprising result that the typical size of a star-forming galaxy of a given mass does not evolve across the redshift range considered, suggesting a universal size-mass relation. Taken in combination, these results indicate a star-forming galaxy population that is statistically similar in physical size, merger rate and mass over the 6 Gyr covered in this study, despite the increase in typical sSFR.

MNRAS in press

References in corpus (17)

• The UKIRT Infrared Deep Sky Survey (UKIDSS)
• The Cosmic Evolution Survey (COSMOS) -- Overview
• The hierarchical formation of the brightest cluster galaxies
• A Semi-Analytic Model for the Co-evolution of Galaxies, Black Holes, and Active Galactic Nuclei
• Formation of Massive Galaxies at High Redshift: Cold Streams, Clumpy Disks and Compact Spheroids
• Detection of quiescent galaxies in a bicolor sequence from z=0-2
• Intense Star Formation within Resolved Compact Regions in a Galaxy at z=2.3
• Kinemetry of SINS High-Redshift Star-Forming Galaxies: Distinguishing Rotating Disks from Major Mergers
• The Redshift Evolution of Wet, Dry, and Mixed Galaxy Mergers from Close Galaxy Pairs in the DEEP2 Galaxy Redshift Survey
• The Structures of Distant Galaxies I: Galaxy Structures and the Merger Rate to z~3 in the Hubble Ultra-Deep Field
• HiZELS: a high redshift survey of H-alpha emitters. I: the cosmic star-formation rate and clustering at z=2.23
• The Structures of Distant Galaxies - III: The Merger History of over 20,000 Massive Galaxies at z < 1.2
• A robust morphological classification of high-redshift galaxies using support vector machines on seeing limited images. I Method description
• The H-alpha Luminosity Function and Star Formation Rate Volume Density at z=0.8 from the NEWFIRM H-alpha Survey
• The Halpha-based Star Formation Rate Density of the Universe at z=0.84
• A Surprisingly High Pair Fraction for Extremely Massive Galaxies at z ~ 3 in the GOODS NICMOS Survey
• The Size Function of Galaxy Disks out to z ~ 1 from the Canada-France-Hawaii-Telescope Legacy Survey

Cited by in corpus (54)

• Introducing the Illustris Project: the evolution of galaxy populations across cosmic time
• The KMOS^3D Survey: design, first results, and the evolution of galaxy kinematics from 0.7<z<2.7
• The Size Evolution of Star-forming and Quenched Galaxies in the IllustrisTNG simulation
• The KMOS Redshift One Spectroscopic Survey (KROSS): Dynamical properties, gas and dark matter fractions of typical z~1 star-forming galaxies
• A chronicle of galaxy mass assembly in the EAGLE simulation
• On the evolution and environmental dependence of the star formation rate versus stellar mass relation since z~2
• The stellar mass function of star-forming galaxies and the mass-dependent SFR function since z=2.23 from HiZELS
• The KMOS Deep Survey (KDS) I: dynamical measurements of typical star-forming galaxies at z $\simeq$ 3.5
• Evolution of the H$\beta$+[OIII] and [OII] luminosity functions and the [OII] star-formation history of the Universe up to $z$ ~ 5 from HiZELS
• A relationship between specific star formation rate and metallicity gradient within z=1 galaxies from KMOS-HiZELS
• A fundamental metallicity relation for galaxies at z = 0.84 - 1.47 from HiZELS
• MAHALO Deep Cluster Survey I. Accelerated and enhanced galaxy formation in the densest regions of a protocluster at z=2.5
• The Grism Lens-Amplified Survey from Space (GLASS). II. Gas-phase metallicity and radial gradients in an interacting system at z~2
• Size evolution of star-forming galaxies with $2<z<4.5$ in the VIMOS Ultra-Deep Survey
• An enhanced merger fraction within the galaxy population of the SSA22 protocluster at z ~ 3.1
• The role of cluster mergers and travelling shocks in shaping the H$\alpha$ luminosity function at $\mathbf{z}\sim 0.2$: `sausage' and `toothbrush' clusters
• The role of galaxy interaction in the SFR-M relation: characterizing morphological properties of Herschel-selected galaxies at 0.2<z<1.5
• Herschel reveals the obscured star formation in HiZELS Hα emitters at z=1.47
• A Census of Sub-kiloparsec Resolution Metallicity Gradients in Star-forming Galaxies at Cosmic Noon from HST Slitless Spectroscopy
• SINFONI-HiZELS: The dynamics, merger rates & metallicity gradients of `typical' star-forming galaxies at $z$ = 0.8-2.2
• Nature of H-alpha selected galaxies at z>2. II. Clumpy galaxies and compact star-forming galaxies
• The structural and size evolution of star-forming galaxies over the last 11 Gyrs
• Signs of environmental effects on star-forming galaxies in the Spiderweb protocluster at z=2.16
• A Catalog of 220 Offset and Dual AGNs: Increased AGN Activation in Major Mergers and Separations under 4 kpc
• The limited role of galaxy mergers in driving stellar mass growth over cosmic time
• The most luminous H$\alpha$ emitters at z~0.8-2.23 from HiZELS: evolution of AGN and star-forming galaxies
• A large narrow band H$\alpha$ survey at $z\sim 0.2$: the bright end of the luminosity function, cosmic variance and clustering across cosmic time
• The dynamics of z=0.8 H-alpha-selected star-forming galaxies from KMOS/CF-HiZELS
• Star Formation and AGN Activity in Interacting Galaxies: A Near-UV Perspective
• Statistics of galaxy mergers: bridging the gap between theory and observation
• An evolving and mass dependent ${\sigma }_{\text{sSFR}}$-${\mathrm{M}}_{\star }$ relation for galaxies
• North Ecliptic Pole merging galaxy catalogue
• Stellar and black hole assembly in z<0.3 infrared-luminous mergers: intermittent starbursts vs. super-Eddington accretion
• KROSS: Mapping the Ha emission across the star-formation sequence at z~1
• Local analogues of high-redshift star-forming galaxies: integral field spectroscopy of green peas
• The Properties of Hα Emission-Line Galaxies at z = 2.24
• The impact from survey depth and resolution on the morphological classification of galaxies
• The Subaru HSC Galaxy Clustering with Photometric Redshift I: Dark Halo Masses Versus Baryonic Properties of Galaxies at 0.3<z<1.4
• The Dynamics and Distribution of Angular Momentum in HiZELS Star-Forming Galaxies at z = 0.8 - 3.3
• The buildup of galaxies and their spheroids: the contributions of mergers, disc instabilities and star formation
• A kpc-scale resolved study of unobscured and obscured star-formation activity in normal galaxies at z = 1.5 and 2.2 from ALMA and HiZELS
• Evolution of mid-infrared galaxy luminosity functions from the entire AKARI NEP-Deep field with new CFHT photometry
• Dynamics and Metallicity of Far-IR Selected Galaxies
• Stellar populations in hosts of giant radio galaxies and their neighbouring galaxies
• Environmental impacts on the rest-frame UV size and morphology ofstar-forming galaxies at $z\sim 2$
• Emission Line Galaxies in the SHARDS Frontier Fields I: Candidate Selection and the Discovery of Bursty Hα Emitters
• The Space Density of Intermediate Redshift, Extremely Compact, Massive Starburst Galaxies
• Explaining the formation of bulges with MOND
• The nature of [S III]λλ9096, 9532 emitters at z = 1.34 and 1.23
• Galaxy pairs in The Three Hundred simulations II: studying bound ones and identifying them via machine learning
• The JWST Emission Line Survey (JELS): The sizes and merger fraction of star-forming galaxies during the Epoch of Reionization
• Heterogeneity of Inverted Calcium II H:K Ratio Cluster Galaxies
• On the dwarf irregular galaxy NGC 6822. I. Young, intermediate and old stellar populations
• The dwarf irregular galaxy NGC 6822. II. Young, intermediate and old stellar populations: comparison between theory and observations