STELLAR KINEMATICS OF z ∼ 2 GALAXIES AND THE INSIDE-OUT GROWTH OF QUIESCENT GALAXIES,

By J. van de Sande, M. Kriek, M. Franx, P. V. van Dokkum, R. Bezanson, R. Bouwens, R. Quadri, Hans-Walter Rix, R. Skelton. 2012

154 citations recorded by the source corpus.

Using stellar kinematics measurements, we investigate the growth of massive, quiescent galaxies from z ∼ 2 to today. We present X-Shooter spectra from the UV to NIR and dynamical mass measurements of five quiescent massive (>1011 M☉) galaxies at z ∼ 2. This triples the sample of z > 1.5 galaxies with well-constrained (δσ < 100 km s−1) velocity dispersion measurements. From spectral population synthesis modeling we find that these galaxies have stellar ages that range from 0.5 to 2 Gyr, with no signs of ongoing star formation. We measure velocity dispersions (290–450 km s−1) from stellar absorption lines and find that they are 1.6–2.1 times higher than those of galaxies in the Sloan Digital Sky Survey at the same mass. Sizes are measured using GALFIT from Hubble Space Telescope Wide Field Camera 3 H160 and UDS K-band images. The dynamical masses correspond well to the spectral energy distribution based stellar masses, with dynamical masses that are ∼15% higher. We find that M*/Mdyn may decrease slightly with time, which could reflect the increase of the dark matter fraction within an increasing effective radius. We combine different stellar kinematic studies from the literature and examine the structural evolution from z ∼ 2 to z ∼ 0: we confirm that at fixed dynamical mass, the effective radius increases by a factor of ∼2.8, and the velocity dispersion decreases by a factor of ∼1.7. The mass density within one effective radius decreases by a factor of ∼20, while within a fixed physical radius (1 kpc) it decreases only mildly (factor of ∼2). When we allow for an evolving mass limit by selecting a population of galaxies at fixed number density, a stronger size growth with time is found (factor of ∼4), velocity dispersion decreases by a factor of ∼1.4, and interestingly, the mass density within 1 kpc is consistent with no evolution. This finding suggests that massive quiescent galaxies at z ∼ 2 grow inside out, consistent with the expectations from minor mergers.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/f07bad866fd970b595e93ad80162c456caca6e82

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In Astronomy and Astrophysics

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

In Instrumentation

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

Citations in the corpus

• 3D-HST+CANDELS: THE EVOLUTION OF THE GALAXY SIZE–MASS DISTRIBUTION SINCE z = 3 (2014, unknown): “Our stellar mass estimates for luminous early-type galaxies have been demonstrated to show small, if any, shifts ( (cid:2) 0.1 dex) compared to dynamical mass measurements over the redshift range 0 < z < 2 (van de Sande et al. 2013; Bezanson et al. 2013; Belli et al. 2014).”
• Near infrared spectroscopy and star-formation histories of 3 ≤ z ≤ 4 quiescent galaxies (2018, background): “…from faint or absent emission lines, their old effective ages (mass- or light-weighted) of more than half a Gyr from absorption lines, or their large masses from kinematics (e.g., Kriek et al. 2006, 2009; van de Sande et al. 2013; Hill et al. 2016; Belli et al. 2017b,a; Glazebrook et al. 2017).”
• 3D-HST WFC3-SELECTED PHOTOMETRIC CATALOGS IN THE FIVE CANDELS/3D-HST FIELDS: PHOTOMETRY, PHOTOMETRIC REDSHIFTS, AND STELLAR MASSES (2014, methodology): “We also include 37 spectroscopic redshifts from IMACS/Magellan (Papovich et al. 2010, and I. Momcheva, private communication), 18 redshifts from Bezanson et al. (2013) and 1 redshift from van de Sande et al. (2013).”
• EVIDENCE FOR WIDE-SPREAD ACTIVE GALACTIC NUCLEUS-DRIVEN OUTFLOWS IN THE MOST MASSIVE z ∼ 1–2 STAR-FORMING GALAXIES (2014, background): “…z ∼ 2 SFGs with large mass surface densities and velocity dispersions (see also Nelson et al. 2014), which may be candidate progenitors of the compact quenched galaxy population in this redshift range (e.g., van Dokkum et al. 2009; Bezanson et al. 2013; van de Sande et al. 2013; Belli et al. 2014).”
• THE MOSFIRE DEEP EVOLUTION FIELD (MOSDEF) SURVEY: REST-FRAME OPTICAL SPECTROSCOPY FOR ∼1500 H-SELECTED GALAXIES AT 1.37 ≤ z ≤ 3.8 ?> (2014, background): “…grow inside out, but the physical mechanism (e.g., minor mergers, progenitor bias, cold streams and in situ star formation) responsible for the growth is still subject to debate (e.g., van de Sande et al. 2013; Newman et al. 2012a; Carollo et al. 2013; Dutton et al. 2011; van Dokkum et al. 2013).”
• FORMING COMPACT MASSIVE GALAXIES (2015, methodology): “Here dynamical mass was calculated using Mσdyn = β(n)σ2obsre G , (18) as derived by Cappellari et al. (2006) and following studies of quiescent galaxies at high redshift (e.g., van de Sande et al. 2013).”
• Structure and Kinematics of Early-Type Galaxies from Integral Field Spectroscopy (2016, background): “…values broadly consistent (but with non-negligible size bias) with the virial predictions inferred from the given masses and radii (Cappellari et al. 2009; Cenarro & Trujillo 2009; Onodera et al. 2010; van de Sande et al. 2011, 2013; Toft et al. 2012; Bezanson et al. 2013; Belli et al. 2014).”