The Evolution of Galaxies at Constant Number Density: A Less Biased View of Star Formation, Quenching, and Structural Formation

Abstract

Due to significant galaxy contamination and impurity in stellar mass selected samples (up to 95% from z=0-3), we examine the star formation history, quenching time-scales, and structural evolution of galaxies using a constant number density selection with data from the UKIDSS Ultra-Deep Survey field. Using this methodology we investigate the evolution of galaxies at a variety of number densities from $z=0-3$. We find that samples chosen at number densities ranging from $3\times 10^{-4}$ to 10${}^{-5}$ galaxies Mpc${}^{-3}$ (corresponding to $z\sim 0.5$ stellar masses of M${}_{\ast }=10^{10.95-11.6}$ M${}_0$) have a star forming blue fraction of $\sim 50$\% at $z\sim 2.5$, which evolves to a nearly $100$\% quenched red and dead population by $z\sim 1$. We also see evidence for number density downsizing, such that the galaxies selected at the lowest densities (highest masses) become a homogeneous red population before those at higher number densities. Examining the evolution of the colours for these systems furthermore shows that the formation redshift of galaxies selected at these number densities is $z_{\mathrm{form}}>3$. The structural evolution through size and Sersic index fits reveal that while there remains evolution in terms of galaxies becoming larger and more concentrated in stellar mass at lower redshifts, the magnitude of the change is significantly smaller than for a mass selected sample. We also find that changes in size and structure continues at $z<1$, and is coupled strongly to passivity evolution. We conclude that galaxy structure is driving the quenching of galaxies, such that galaxies become concentrated before they become passive.

MNRAS in press

References in corpus (18)

• The UKIRT Infrared Deep Sky Survey (UKIDSS)
• Mass and environment as drivers of galaxy evolution in SDSS and zCOSMOS and the origin of the Schechter function
• EAZY: A Fast, Public Photometric Redshift Code
• Detection of quiescent galaxies in a bicolor sequence from z=0-2
• Size evolution of the most massive galaxies at 1.7<z<3 from GOODS NICMOS survey imaging
• The mass evolution of the first galaxies: stellar mass functions and star formation rates at $4<z<7$ in the CANDELS GOODS-South field
• The Structures of Distant Galaxies I: Galaxy Structures and the Merger Rate to z~3 in the Hubble Ultra-Deep Field
• The Fundamental Properties of Galaxies and a New Galaxy Classification System
• Radio imaging of the Subaru/XMM-Newton Deep Field - I. The 100-microJy catalogue, optical identifications, and the nature of the faint radio source population
• The Subaru/XMM-Newton Deep Survey (SXDS): III. X-Ray Data
• The Structures of Distant Galaxies - III: The Merger History of over 20,000 Massive Galaxies at z < 1.2
• GALAPAGOS: From Pixels to Parameters
• Galaxy And Mass Assembly: Deconstructing Bimodality - I. Red ones and blue ones
• The Properties and Evolution of a K-band Selected Sample of Massive Galaxies at z~0.4 - 2 in the Palomar/DEEP2 Survey
• Deconstructing the Galaxy Stellar Mass Function with UKIDSS and CANDELS: the Impact of Colour, Structure and Environment
• The Bulge-Disk Decomposed Evolution of Massive Galaxies at 1<z<3 in CANDELS
• Minor vs Major Mergers: The Stellar Mass Growth of Massive Galaxies from z=3 using Number Density Selection Techniques
• Tracing galaxy populations through cosmic time: A critical test of methods for connecting the same galaxies between different redshifts at $z<3$

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• The evolution of post-starburst galaxies from z=2 to z= 0.5
• A consistent measure of the merger histories of massive galaxies using close-pair statistics I: Major mergers at $z<3.5$
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• The COSMOS2015 galaxy stellar mass function: 13 billion years of stellar mass assembly in 10 snapshots
• Demographics of Star-forming Galaxies since $z\sim 2.5$. I. The $UVJ$ Diagram in CANDELS
• The mass, colour, and structural evolution of today's massive galaxies since z~5
• A direct measurement of galaxy major and minor merger rates and stellar mass accretion histories at $z<3$ using galaxy pairs in the REFINE survey
• Galaxy Evolution in all Five CANDELS Fields and IllustrisTNG: Morphological, Structural, and the Major Merger Evolution to $z\sim 3$
• Galaxy Mergers in the Epoch of Reionization I: A JWST Study of Pair Fractions, Merger Rates, and Stellar Mass Accretion Rates at $z=4.5-11.5$
• Unbiased Differential Size Evolution and the Inside-Out Growth of Galaxies in the Deep CANDELS GOODS Fields at $1\le z\le 7$
• Observations of the Initial Formation and Evolution of Spiral galaxies at $1<z<3$ in the CANDELS fields
• Galaxy Structure, Stellar Populations, and Star Formation Quenching at 0.6 $\lesssim$ $z$ $\lesssim$ 1.2
• Surface Brightness Evolution of Galaxies in the CANDELS GOODS Fields up to $z\sim 6$: High-z Galaxies are Unique or Remain Undetected
• Stellar populations, stellar masses and the formation of galaxy bulges and discs at $z<3$ in CANDELS
• NUV signatures of environment driven galaxy quenching in SDSS groups
• Rapidly quenched galaxies in the Simba cosmological simulation and observations
• The growth of disks and bulges during hierarchical galaxy formation. II: metallicity, stellar populations and dynamical evolution
• Morphological Transformation and Star Formation Quenching of Massive Galaxies at 0.5 < z < 2.5 in 3D-HST/CANDELS
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