THE GROWTH OF MASSIVE GALAXIES SINCE z = 2

By P. V. van Dokkum, K. Whitaker, G. Brammer, M. Franx, M. Kriek, I. Labbé, D. Marchesini, R. Quadri, R. Bezanson, G. Illingworth and 4 more. 2009

571 citations recorded by the source corpus.

We study the growth of massive galaxies from z = 2 to the present using data from the NOAO/Yale NEWFIRM Medium Band Survey. The sample is selected at a constant number density of n = 2 × 10−4 Mpc−3, so that galaxies at different epochs can be compared in a meaningful way. We show that the stellar mass of galaxies at this number density has increased by a factor of ≈2 since z = 2, following the relation log Mn(z) = 11.45 − 0.15z. In order to determine at what physical radii this mass growth occurred, we construct very deep stacked rest-frame R-band images of galaxies with masses near Mn(z), at redshifts 〈z〉 = 0.6, 1.1, 1.6, and 2.0. These image stacks of typically 70–80 galaxies enable us to characterize the stellar distribution to surface brightness limits of ∼28.5 mag arcsec−2. We find that massive galaxies gradually built up their outer regions over the past 10 Gyr. The mass within a radius of r = 5 kpc is nearly constant with redshift, whereas the mass at 5 kpc < r < 75 kpc has increased by a factor of ∼4 since z = 2. Parameterizing the surface brightness profiles, we find that the effective radius and Sersic n parameter evolve as re ∝ (1 + z)−1.3 and n ∝ (1 + z)−1.0, respectively. The data demonstrate that massive galaxies have grown mostly inside-out, assembling their extended stellar halos around compact, dense cores with possibly exponential radial density distributions. Comparing the observed mass evolution to the average star formation rates of the galaxies we find that the growth is likely dominated by mergers, as in situ star formation can only account for ∼20% of the mass buildup from z = 2 to z = 0. A direct consequence of these results is that massive galaxies do not evolve in a self-similar way: their structural profiles change as a function of redshift, complicating analyses which (often implicitly) assume self-similarity. The main uncertainties in this study are possible redshift-dependent systematic errors in the total stellar masses and the conversion from light-weighted to mass-weighted radial profiles.

Subfields: Astronomy and Astrophysics, Instrumentation, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/83be2e86c49360186841bb1d32aa467490f86bde

How researchers see this paper

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In Astronomy and Astrophysics

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

In Instrumentation

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

In Statistical and Nonlinear Physics

1. C. Conroy
2. P. V. van Dokkum
3. M. Franx
4. Risa Wechsler
5. P. Behroozi
6. A. Dekel
7. R. Somerville
8. T. Naab

Citations in the corpus

• PRIMUS: CONSTRAINTS ON STAR FORMATION QUENCHING AND GALAXY MERGING, AND THE EVOLUTION OF THE STELLAR MASS FUNCTION FROM z = 0–1 (2013, background): “…both star formation and mergers will increase Mc without changing the number density, while the transformation of one galaxy type into another (e.g., due to star formation quenching) will tend to decrease Mc at a given cumulative number density (van Dokkum et al. 2010; Brammer et al. 2011).”
• THE MAJOR AND MINOR GALAXY MERGER RATES AT z < 1.5 (2011, background): “Galaxy samples selected with a constant number density may do a better job of matching descendantprogenitor galaxies over a range of redshifts (van Dokkum et al. 2010; Papovich et al. 2010), and matching galaxies to constant mass halos (at Mhalo ∼ 10 11−12M⊙; Zheng et al. 2007).”
• The formation of massive, compact galaxies at z = 2 in the Illustris simulation (2014, background): “06 67 v3 [ as tr oph effect (Belli, Newman & Ellis 2014; Belli et al. 2014), however, and there is evidence that high-redshift compact galaxies have grown into the centers of today’s giant elliptical galaxies (van Dokkum et al. 2010, 2014).”
• THE SPECTRAL ENERGY DISTRIBUTIONS OF z ∼ 8 GALAXIES FROM THE IRAC ULTRA DEEP FIELDS: EMISSION LINES, STELLAR MASSES, AND SPECIFIC STAR FORMATION RATES AT 650 MYR (2012, result): “This a factor of ∼ 2 slower than the power law derived by Fumagalli et al. (2012) over 0 < z < 2, but in agreement with their model which assumes that the cumulative number density of progenitors at higher redshift remains constant (e.g., Dokkum et al. 2010, Papovich et al. 2011).”
• CANDELS: THE COSMIC ASSEMBLY NEAR-INFRARED DEEP EXTRAGALACTIC LEGACY SURVEY (2011, unknown): “If these sizes are correct, the implication is that massive spheroids must have accreted considerable stellar mass after z ≈ 2 and that their extended stellar envelopes grew by dry minor mergers (Naab et al. 2009; van Dokkum et al. 2010).”
• The DEEP3 Galaxy Redshift Survey: the impact of environment on the size evolution of massive early-type galaxies at intermediate redshift (2011, background): “…types at z ∼ 2 are found to only exceed local C© 2011 The Authors Monthly Notices of the Royal Astronomical Society C© 2011 RAS nras/article-abstract/419/4/3018/2908043 by guest on 15 M arch 2020 measurements by a factor of 2–3 (Bezanson et al. 2009; Hopkins et al. 2009a; van Dokkum et al. 2010).”
• The VISTA deep extragalactic observations (VIDEO) survey (2012, background): “Given the seeing constraints (see Section 5) and accounting for the apparent size evolution of massive passive galaxies at high redshift (e.g. Zirm et al. 2007; van Dokkum et al. 2010; McLure et al. 2012), we therefore define our 5σ Ks-band limit as Ks = 23.5 in a 2 arcsec diameter aperture.”
• THE MAJORITY OF COMPACT MASSIVE GALAXIES AT z ∼ 2 ARE DISK DOMINATED (2011, background): “On the other hand, given their high stellar masses, clustering properties (e.g., Quadri et al. 2007; Hartley et al. 2010), and number densities (e.g., van Dokkum et al. 2010), these objects must evolve into very massive, large, pressuresupported, bulge-dominated galaxies in the present-day universe.”
• THE MOSFIRE DEEP EVOLUTION FIELD (MOSDEF) SURVEY: REST-FRAME OPTICAL SPECTROSCOPY FOR ∼1500 H-SELECTED GALAXIES AT 1.37 ≤ z ≤ 3.8 ?> (2014, background): “By tracing both the evolution in stellar mass and SFR of a complete galaxy sample, we can constrain the rate and by which mechanism (star formation vs. mergers) galaxies grow (e.g., van Dokkum et al. 2010; Reddy et al. 2012b).”
• The ATLAS3D project – XX. Mass–size and mass–σ distributions of early-type galaxies: bulge fraction drives kinematics, mass-to-light ratio, molecular gas fraction and stellar initial mass function (2012, result): “This seems consistent with the shape of the photometric profiles of the early ETGs (Bezanson et al. 2009; Hopkins et al. 2009a; van Dokkum et al. 2010; Hilz et al. 2013).”
• Galactic accretion and the outer structure of galaxies in the CDM model (2013, background): “/M = 11.45 ± 0.15 (appendix D of van Dokkum et al. 2010).”
• A LARGE POPULATION OF MASSIVE COMPACT POST-STARBURST GALAXIES AT z > 1: IMPLICATIONS FOR THE SIZE EVOLUTION AND QUENCHING MECHANISM OF QUIESCENT GALAXIES (2011, methodology): “As the simple model used in this paper does not take into account growth due to mergers, we repeat the analysis selecting galaxies (both quiescent and star-forming) at a constant number density of 2 × 10−4 Mpc−3, following van Dokkum et al. (2010).”
• UV LUMINOSITY FUNCTIONS AT REDSHIFTS z ∼ 4 TO z ∼ 10: 10,000 GALAXIES FROM HST LEGACY FIELDS (2014, background): “…universe largely grow in a self-similar fashion, so that nth brightest or most massive galaxy at some point in cosmic time generally maintains its rough ranking in terms of brightness or mass at some later point in cosmic time (van Dokkum et al. 2010; Papovich et al. 2011; Lundgren et al. 2014).”
• THE COSMOLOGICAL SIZE AND VELOCITY DISPERSION EVOLUTION OF MASSIVE EARLY-TYPE GALAXIES (2011, background): “Observations of the growth of massive galaxies since z ≈ 2 selected at constant number density (van Dokkum et al. 2010) indicate that they grow inside-out.”
• Deriving Physical Properties from Broadband Photometry with Prospector: Description of the Model and a Demonstration of its Accuracy Using 129 Galaxies in the Local Universe (2016, background): “Massive galaxies are thought to double in stellar mass from z=2 to the present epoch (e.g., van Dokkum et al. 2010; Patel et al. 2013b).”
• Near infrared spectroscopy and star-formation histories of 3 ≤ z ≤ 4 quiescent galaxies (2018, background): “…the proportion of star-forming objects among massive galaxies, compact galaxies, or within over-dense structures was larger in the past (e.g., Butcher & Oemler 1978; Elbaz et al. 2007; van Dokkum et al. 2010; Brammer et al. 2011; Barro et al. 2013, 2016; Wang et al. 2016; Elbaz et al. 2017).”