SMOOTH(ER) STELLAR MASS MAPS IN CANDELS: CONSTRAINTS ON THE LONGEVITY OF CLUMPS IN HIGH-REDSHIFT STAR-FORMING GALAXIES

By S. Wuyts, N. F. Förster Schreiber, R. Genzel, Yicheng Guo, G. Barro, Eric F. Bell, A. Dekel, S. Faber, H. Ferguson, M. Giavalisco and 15 more. 2012

228 citations recorded by the source corpus.

We perform a detailed analysis of the resolved colors and stellar populations of a complete sample of 323 star-forming galaxies (SFGs) at 0.5 < z < 1.5 and 326 SFGs at 1.5 < z < 2.5 in the ERS and CANDELS-Deep region of GOODS-South. Galaxies were selected to be more massive than 1010 M☉ and have specific star formation rates (SFRs) above 1/tH. We model the seven-band optical ACS + near-IR WFC3 spectral energy distributions of individual bins of pixels, accounting simultaneously for the galaxy-integrated photometric constraints available over a longer wavelength range. We analyze variations in rest-frame color, stellar surface mass density, age, and extinction as a function of galactocentric radius and local surface brightness/density, and measure structural parameters on luminosity and stellar mass maps. We find evidence for redder colors, older stellar ages, and increased dust extinction in the nuclei of galaxies. Big star-forming clumps seen in star formation tracers are less prominent or even invisible in the inferred stellar mass distributions. Off-center clumps contribute up to ∼20% to the integrated SFR, but only 7% or less to the integrated mass of all massive SFGs at z ∼ 1 and z ∼ 2, with the fractional contributions being a decreasing function of wavelength used to select the clumps. The stellar mass profiles tend to have smaller sizes and M20 coefficients, and higher concentration and Gini coefficients than the light distribution. Our results are consistent with an inside-out disk growth scenario with brief (100–200 Myr) episodic local enhancements in star formation superposed on the underlying disk. Alternatively, the young ages of off-center clumps may signal inward clump migration, provided this happens efficiently on the order of an orbital timescale.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/377aaba49b1136c535bb2b4b9f1834dde48c3148

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In Astronomy and Astrophysics

1. P. Hopkins
2. L. Hernquist
3. A. Dekel
4. R. Somerville
5. R. Dav'e
6. P. V. van Dokkum
7. T. Naab
8. C. Conroy

In Instrumentation

1. P. Hopkins
2. L. Hernquist
3. A. Dekel
4. P. V. van Dokkum
5. R. Dav'e
6. R. Somerville
7. C. Conroy
8. M. Franx

Citations in the corpus

• 3D-HST+CANDELS: THE EVOLUTION OF THE GALAXY SIZE–MASS DISTRIBUTION SINCE z = 3 (2014, unknown): “However, such scenarios seem implausible as the implied color and mass-to-light ratio gradients of such galaxies would likely be stronger than observed (Wuyts et al. 2012).”
• The Evolution of Galaxy Structure Over Cosmic Time (2014, methodology): “Wuyts et al. (2012) find that the nuclei of star forming galaxies are redder and have older ages than their outer parts.”
• THE STAR FORMATION MASS SEQUENCE OUT TO z = 2.5 (2012, background): “…evolves with redshift, while the normalization β has a stronger evolution: α(z)=0.70− 0.13z (2) β(z)=0.38 + 1.14z − 0.19z2 (3) Previous studies have found hints of a similar trend for the slope to flatten toward z ∼ 1 or high M⋆ (e.g., Noeske et al. 2007; Karim et al. 2011; Wuyts et al. 2012).”
• A CANDELS–3D-HST SYNERGY: RESOLVED STAR FORMATION PATTERNS AT 0.7 < z < 1.5 (2013, methodology): “As discussed by Wuyts et al. (2012), SFGs feature radial gradients in dust extinction.”
• Physical Models of Galaxy Formation in a Cosmological Framework (2014, background): “Many z ∼ 2 disks also have large, bright clumps that comprise a substantial portion of the disk star formation (Guo et al. 2012), though significantly less of the stellar mass (Wuyts et al. 2012), and are generating outflows (Genzel et al. 2011).”
• THE LONG LIVES OF GIANT CLUMPS AND THE BIRTH OF OUTFLOWS IN GAS-RICH GALAXIES AT HIGH REDSHIFT (2013, background): “Second, the clumps are much fainter in near-infrared imaging (Elmegreen et al. 2009), indicating that their masses are relatively limited in the old stellar components, and indeed the typical ages of the stellar populations contained in clumps are rarely larger than ≤ 200Myr (Wuyts et al. 2012).”
• THE KMOS3D SURVEY: DESIGN, FIRST RESULTS, AND THE EVOLUTION OF GALAXY KINEMATICS FROM 0.7 ⩽ z ⩽ 2.7 (2014, unknown): “…stellar populations, dust extinction and stellar mass maps that will complement the kinematics, star formation and nebular emission data derived from KMOS for a combined view of resolved gas and stellar profiles of individual galaxies (Wuyts et al. 2012, 2013; Nelson et al. 2013; Lang et al. 2014).”
• Structural and Star-forming Relations since z ∼ 3: Connecting Compact Star-forming and Quiescent Galaxies (2015, background): “This is a better approximation for quiescent galaxies, which exhibit only weak color gradients (e.g., Guo et al. 2012; Szomoru et al. 2012; Wuyts et al. 2012).”
• PHIBSS: MOLECULAR GAS CONTENT AND SCALING RELATIONS IN z ∼ 1–3 MASSIVE, MAIN-SEQUENCE STAR-FORMING GALAXIES (2012, background): “Rest-frame UV- and B-band HST images of many z~1-1.5 SFGs and almost all z~2-3 SFGs are clumpy and asymmetric, even if rotational support dominates (Figures 2-5, Elmegreen et al. 2005, Wuyts et al. 2012).”
• Introducing the Illustris Project: the evolution of galaxy populations across cosmic time (2014, methodology): “…445, 175–200 (2014) Downloaded from https://academic.oup.com/mnras/article-abstract/445/1/175/985625 by University of Cambridge user on 18 July 2018 will be presented in future work (Snyder et al., in preparation), but the qualitative agreement with observations is worth noting (Wuyts et al. 2012).”
• A LINK BETWEEN STAR FORMATION QUENCHING AND INNER STELLAR MASS DENSITY IN SLOAN DIGITAL SKY SURVEY CENTRAL GALAXIES (2013, methodology): “This effect has been called “outshining” in some contexts (Reddy et al. 2012; Wuyts et al. 2012), whereby light from recently formed stars biases measurements of radii, stellar population ages, or other parameters.”
• The star formation history of CALIFA galaxies: Radial structures (2013, methodology): “…the rest frame optical emission of galaxies at redshift z ∼ 2, and to obtain spatially resolved maps of the stellar mass by fitting the SED in each individual pixel (Wuyts et al. 2012), or simply using an empirical relation between the rest-frame color and stellar M/L ratio (Szomoru et al. 2012).”
• MORPHOLOGIES OF ∼190,000 GALAXIES AT z = 0–10 REVEALED WITH HST LEGACY DATA. I. SIZE EVOLUTION (2015, background): “Similarly, van der Wel et al. (2014) have found that re,major is typically smaller in redder bands for SFGs at z ∼ 0 − 2 (see also, e.g., Szomoru et al. 2011; Wuyts et al. 2012).”
• Evolution of density profiles in high-z galaxies: compaction and quenching inside-out (2015, background): “Several studies have investigated the stellar mass density distribution within galaxies at high redshifts (e.g., Elmegreen et al. 2009; Förster Schreiber et al. 2011; Wuyts et al. 2012; van Dokkum et al. 2013; Patel et al. 2013; Lang et al. 2014; Morishita et al. 2015).”
• The Morphologies of Massive Galaxies at 1<z<3 in the CANDELS-UDS Field: Compact Bulges, and the Rise and Fall of Massive Disks (2012, background): “…this view of the potential importance of the observed clumps in building bulges (e.g. Guo et al. 2012) has been challenged observationally (e.g. Wuyts et al. 2012) and theoretically C© 2012 The Authors, MNRAS 427, 1666–1701 Monthly Notices of the Royal Astronomical Society C© 2012…”
• REGULARITY UNDERLYING COMPLEXITY: A REDSHIFT-INDEPENDENT DESCRIPTION OF THE CONTINUOUS VARIATION OF GALAXY-SCALE MOLECULAR GAS PROPERTIES IN THE MASS-STAR FORMATION RATE PLANE (2013, unknown): “…signature of violent disk instabilities in gas-rich high-redshift galaxies (e.g., Agertz et al. 2009, Ceverino et al. 2010, Förster Schreiber et al. 2011, Swinbank et al. 2011, Wuyts et al. 2012) this observation thus provides independent evidence for increasing gas fractions within the MS.”
• The SINS/zC-SINF Survey of z ∼ 2 Galaxy Kinematics: SINFONI Adaptive Optics–assisted Data and Kiloparsec-scale Emission-line Properties (2018, background): “…with an increasingly important central stellar bulge-like component at higher galaxy masses and clumpier appearances towards shorter wavelengths (e.g., Wuyts et al. 2011b, 2012, 2013; Nelson et al. 2013, 2016b; Lang et al. 2014, see also Elmegreen et al. 2007, 2009; Law et al. 2012a; Tacchella et…”
• Feedback-regulated star formation in molecular clouds and galactic discs (2013, background): “We are also interested in high-redshift, gas-rich star-forming galaxies, for which the lifetime of the massive star-forming clumps are inferred to be ≈ 100− 200 Myr (Wuyts et al. 2012).”