Color gradients and half-mass radii of galaxies out to $z=2$ in the CANDELS/3D-HST fields: further evidence for important differences in the evolution of mass-weighted and light-weighted sizes

Abstract

Recent studies have indicated that the ratio between half-mass and half-light radii, $r_{\mathrm{mass}}/r_{\mathrm{light}}$, varies significantly as a function of stellar mass and redshift, complicating the interpretation of the ubiquitous $r_{\mathrm{light}}-M_{\ast }$ relation. To investigate, in this study we construct the light and color profiles of $\sim 3000$ galaxies at $1<z<2$ with $\log M_{\ast }/M_{\odot }>10.25$ using $\text{imcascade}$, a Bayesian implementation of the Multi-Gaussian expansion (MGE) technique. $\text{imcascade}$ flexibly represents galaxy profiles using a series of Gaussians, free of any a-priori parameterization. We find that both star-forming and quiescent galaxies have on average negative color gradients. For star forming galaxies, we find steeper gradients that evolve with redshift and correlate with dust content. Using the color gradients as a proxy for gradients in the $M/L$ ratio we measure half mass radii for our sample of galaxies. There is significant scatter in individual $r_{\mathrm{mass}}/r_{\mathrm{light}}$ ratios, which is correlated with variation in the color gradients. We find that the median $r_{\mathrm{mass}}/r_{\mathrm{light}}$ ratio evolves from 0.75 at $z=2$ to 0.5 at $z=1$, consistent with previous results. We characterize the $r_{\mathrm{mass}}-M_{\ast }$ relation and we find that it has a shallower slope and shows less redshift evolution than the $r_{\mathrm{light}}-M_{\ast }$ relation. This applies both to star-forming and quiescent galaxies. We discuss some of the implications of using $r_{\mathrm{mass}}$ instead of $r_{\mathrm{light}}$, including an investigation of the size-inclination bias and a comparison to numerical simulations.

Submitted to ApJ: Please find catalog of size and color gradient measurements here: https://raw.githubusercontent.com/tbmiller-astro/tbmiller-astro.github.io/main/assets/Miller2022_morph_CANDELs.txt

References in corpus (34)

• The NumPy array: a structure for efficient numerical computation
• The EAGLE project: Simulating the evolution and assembly of galaxies and their environments
• EAZY: A Fast, Public Photometric Redshift Code
• The EAGLE simulations of galaxy formation: calibration of subgrid physics and model variations
• 3D-HST+CANDELS: The Evolution of the Galaxy Size-Mass Distribution since $z=3$
• 3D-HST WFC3-selected Photometric Catalogs in the Five CANDELS/3D-HST Fields: Photometry, Photometric Redshifts and Stellar Masses
• Detection of quiescent galaxies in a bicolor sequence from z=0-2
• The Size Evolution of Star-forming and Quenched Galaxies in the IllustrisTNG simulation
• Improved Dynamical Constraints on the Masses of the Central Black Holes in Nearby Low-mass Early-type Galactic Nuclei And the First Black Hole Determination for NGC 205
• Half-mass radii for ~7,000 galaxies at 1.0 < z < 2.5: most of the evolution in the mass-size relation is due to color gradients
• Spatially Resolved Star Formation and Inside-out Quenching in the TNG50 Simulation and 3D-HST Observations
• A physically motivated definition for the size of galaxies in an era of ultra-deep imaging
• Modelling the spectral energy distribution of galaxies. IV Correcting apparent disk scalelengths and central surface brightnesses for the effect of dust at optical and near-infrared wavelengths
• GOODS-ALMA 2.0: Source catalog, number counts, and prevailing compact sizes in 1.1 mm galaxies
• Hyper Suprime-Cam Subaru Strategic Program: A Mass-Dependent Slope of the Galaxy Size-Mass Relation at $z<1$
• Beyond UVJ: More Efficient Selection of Quiescent Galaxies With UV / Mid-IR Fluxes
• Structural evolution in massive galaxies at z~2
• Rest-frame near-infrared sizes of galaxies at cosmic noon: objects in JWST's mirror are smaller than they appeared
• Half-mass radii of quiescent and star-forming galaxies evolve slowly from 0 < z < 2.5: implications for galaxy assembly histories
• The Stellar Initial Mass Function in Early-Type Galaxies From Absorption Line Spectroscopy. IV. A Super-Salpeter IMF in the center of NGC 1407 from Non-Parametric Models
• The relationship between fine galaxy stellar morphology and star formation activity in cosmological simulations: a deep learning view
• Dissecting the size-mass and ${\Sigma }_1$-mass relations at 1.0 < z < 2.5: galaxy mass profiles and color gradients as a function of spectral shape
• UVI colour gradients of 0.4<z<1.4 star-forming main sequence galaxies in CANDELS: dust extinction and star formation profiles
• Galaxy Sizes Since $z=2$ from the Perspective of Stellar Mass Distribution within Galaxies
• Realistic mock observations of the sizes and stellar mass surface densities of massive galaxies in FIRE-2 zoom-in simulations
• A New View of the Size-Mass Distribution of Galaxies: Using $r_{20}$ and $r_{80}$ instead of $r_{50}$
• The Origins of UV-optical Color Gradients in Star-forming Galaxies at z ~ 2: Predominant Dust Gradients But Negligible sSFR Gradients
• Deprojecting Sersic Profiles for Arbitrary Triaxial Shapes: Robust Measures of Intrinsic and Projected Galaxy Sizes
• Mass-to-Light Ratios of Spatially Resolved Stellar Populations in M31
• The half mass radius of MaNGA galaxies: Effect of IMF gradients
• The differences between mass- and light-derived structural parameters over time for MaNGA Elliptical galaxies
• Bayesian fitting of multi-Gaussian expansion models to galaxy images
• Variation in the stellar initial mass function from the chromospheric activity of M dwarfs in early-type galaxies
• Anomalously Narrow Linewidths of Compact Massive Star-Forming Galaxies at z~2.3: A Possible Inclination Bias in the Size-Mass Plane

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