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Title: KMOS{sup 3D} Reveals Low-level Star Formation Activity in Massive Quiescent Galaxies at 0.7 < z < 2.7

Abstract

We explore the H α emission in the massive quiescent galaxies observed by the KMOS{sup 3D} survey at 0.7 < z < 2.7. The H α line is robustly detected in 20 out of 120 UVJ -selected quiescent galaxies, and we classify the emission mechanism using the H α line width and the [N ii]/H α line ratio. We find that AGNs are likely to be responsible for the line emission in more than half of the cases. We also find robust evidence for star formation activity in nine quiescent galaxies, which we explore in detail. The H α kinematics reveal rotating disks in five of the nine galaxies. The dust-corrected H α star formation rates are low (0.2–7 M {sub ⊙} yr{sup −1}), and place these systems significantly below the main sequence. The 24 μ m-based, infrared luminosities, instead, overestimate the star formation rates. These galaxies present a lower gas-phase metallicity compared to star-forming objects with similar stellar mass, and many of them have close companions. We therefore conclude that the low-level star formation activity in these nine quiescent galaxies is likely to be fueled by inflowing gas or minor mergers, and could be a sign of rejuvenation events.

Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;  [1];  [2]; ;  [3] more »; « less
  1. Max-Planck-Institut für Extraterrestrische Physik (MPE), Giessenbachstr. 1, D-85748 Garching (Germany)
  2. Department of Physics, University of Bath, Claverton Down, Bath, BA2 7AY (United Kingdom)
  3. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
Publication Date:
OSTI Identifier:
22654475
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 841; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BALMER LINES; COMPARATIVE EVALUATIONS; EMISSION; EVOLUTION; GALAXIES; LINE WIDTHS; LUMINOSITY; MASS; METALLICITY; RED SHIFT; STARS

Citation Formats

Belli, Sirio, Genzel, Reinhard, Förster Schreiber, Natascha M., Wisnioski, Emily, Wilman, David J., Mendel, J. Trevor, Beifiori, Alessandra, Bender, Ralf, Burkert, Andreas, Chan, Jeffrey, Davies, Rebecca L., Davies, Ric, Fabricius, Maximilian, Fossati, Matteo, Galametz, Audrey, Lang, Philipp, Lutz, Dieter, Wuyts, Stijn, Brammer, Gabriel B., Momcheva, Ivelina G., and and others. KMOS{sup 3D} Reveals Low-level Star Formation Activity in Massive Quiescent Galaxies at 0.7 < z < 2.7. United States: N. p., 2017. Web. doi:10.3847/2041-8213/AA70E5.
Belli, Sirio, Genzel, Reinhard, Förster Schreiber, Natascha M., Wisnioski, Emily, Wilman, David J., Mendel, J. Trevor, Beifiori, Alessandra, Bender, Ralf, Burkert, Andreas, Chan, Jeffrey, Davies, Rebecca L., Davies, Ric, Fabricius, Maximilian, Fossati, Matteo, Galametz, Audrey, Lang, Philipp, Lutz, Dieter, Wuyts, Stijn, Brammer, Gabriel B., Momcheva, Ivelina G., & and others. KMOS{sup 3D} Reveals Low-level Star Formation Activity in Massive Quiescent Galaxies at 0.7 < z < 2.7. United States. doi:10.3847/2041-8213/AA70E5.
Belli, Sirio, Genzel, Reinhard, Förster Schreiber, Natascha M., Wisnioski, Emily, Wilman, David J., Mendel, J. Trevor, Beifiori, Alessandra, Bender, Ralf, Burkert, Andreas, Chan, Jeffrey, Davies, Rebecca L., Davies, Ric, Fabricius, Maximilian, Fossati, Matteo, Galametz, Audrey, Lang, Philipp, Lutz, Dieter, Wuyts, Stijn, Brammer, Gabriel B., Momcheva, Ivelina G., and and others. Sat . "KMOS{sup 3D} Reveals Low-level Star Formation Activity in Massive Quiescent Galaxies at 0.7 < z < 2.7". United States. doi:10.3847/2041-8213/AA70E5.
@article{osti_22654475,
title = {KMOS{sup 3D} Reveals Low-level Star Formation Activity in Massive Quiescent Galaxies at 0.7 < z < 2.7},
author = {Belli, Sirio and Genzel, Reinhard and Förster Schreiber, Natascha M. and Wisnioski, Emily and Wilman, David J. and Mendel, J. Trevor and Beifiori, Alessandra and Bender, Ralf and Burkert, Andreas and Chan, Jeffrey and Davies, Rebecca L. and Davies, Ric and Fabricius, Maximilian and Fossati, Matteo and Galametz, Audrey and Lang, Philipp and Lutz, Dieter and Wuyts, Stijn and Brammer, Gabriel B. and Momcheva, Ivelina G. and and others},
abstractNote = {We explore the H α emission in the massive quiescent galaxies observed by the KMOS{sup 3D} survey at 0.7 < z < 2.7. The H α line is robustly detected in 20 out of 120 UVJ -selected quiescent galaxies, and we classify the emission mechanism using the H α line width and the [N ii]/H α line ratio. We find that AGNs are likely to be responsible for the line emission in more than half of the cases. We also find robust evidence for star formation activity in nine quiescent galaxies, which we explore in detail. The H α kinematics reveal rotating disks in five of the nine galaxies. The dust-corrected H α star formation rates are low (0.2–7 M {sub ⊙} yr{sup −1}), and place these systems significantly below the main sequence. The 24 μ m-based, infrared luminosities, instead, overestimate the star formation rates. These galaxies present a lower gas-phase metallicity compared to star-forming objects with similar stellar mass, and many of them have close companions. We therefore conclude that the low-level star formation activity in these nine quiescent galaxies is likely to be fueled by inflowing gas or minor mergers, and could be a sign of rejuvenation events.},
doi = {10.3847/2041-8213/AA70E5},
journal = {Astrophysical Journal Letters},
number = 1,
volume = 841,
place = {United States},
year = {Sat May 20 00:00:00 EDT 2017},
month = {Sat May 20 00:00:00 EDT 2017}
}
  • We present the KMOS{sup 3D} survey, a new integral field survey of over 600 galaxies at 0.7 < z < 2.7 using KMOS at the Very Large Telescope. The KMOS{sup 3D} survey utilizes synergies with multi-wavelength ground- and space-based surveys to trace the evolution of spatially resolved kinematics and star formation from a homogeneous sample over 5 Gyr of cosmic history. Targets, drawn from a mass-selected parent sample from the 3D-HST survey, cover the star formation-stellar mass (M {sub *}) and rest-frame (U – V) – M {sub *} planes uniformly. We describe the selection of targets, the observations, and themore » data reduction. In the first-year of data we detect Hα emission in 191 M {sub *} = 3 × 10{sup 9}-7 × 10{sup 11} M {sub ☉} galaxies at z = 0.7-1.1 and z = 1.9-2.7. In the current sample 83% of the resolved galaxies are rotation dominated, determined from a continuous velocity gradient and v {sub rot}/σ{sub 0} > 1, implying that the star-forming ''main sequence'' is primarily composed of rotating galaxies at both redshift regimes. When considering additional stricter criteria, the Hα kinematic maps indicate that at least ∼70% of the resolved galaxies are disk-like systems. Our high-quality KMOS data confirm the elevated velocity dispersions reported in previous integral field spectroscopy studies at z ≳ 0.7. For rotation-dominated disks, the average intrinsic velocity dispersion decreases by a factor of two from 50 km s{sup –1}at z ∼ 2.3 to 25 km s{sup –1}at z ∼ 0.9. Combined with existing results spanning z ∼ 0-3, we show that disk velocity dispersions follow an evolution that is consistent with the dependence of velocity dispersion on gas fractions predicted by marginally stable disk theory.« less
  • Scaling relations between galaxy structures and dynamics have been studied extensively for early- and late-type galaxies, both in the local universe and at high redshifts. The abundant differences between the properties of disky and elliptical, or star-forming and quiescent, galaxies seem to be characteristic of the local universe; such clear distinctions begin to disintegrate as observations of massive galaxies probe higher redshifts. In this paper we investigate the existence of the mass fundamental plane of all massive galaxies (σ ≳ 100 km s{sup –1}). This work includes local galaxies (0.05 < z < 0.07) from the Sloan Digital Sky Survey,more » in addition to 31 star-forming and 72 quiescent massive galaxies at intermediate redshift (z ∼ 0.7) with absorption-line kinematics from deep Keck-DEIMOS spectra and structural parameters from Hubble Space Telescope imaging. In two-parameter scaling relations, star-forming and quiescent galaxies differ structurally and dynamically. However, we show that massive star-forming and quiescent galaxies lie on nearly the same mass fundamental plane, or the relationship between stellar mass surface density, stellar velocity dispersion, and effective radius. The scatter in this relation (measured about log σ) is low: 0.072 dex (0.055 dex intrinsic) at z ∼ 0 and 0.10 dex (0.08 dex intrinsic) at z ∼ 0.7. This 3D surface is not unique: virial relations, with or without a dependence on luminosity profile shapes, can connect galaxy structures and stellar dynamics with similar scatter. This result builds on the recent finding that mass fundamental plane has been stable for early-type galaxies since z ∼ 2. As we now find that this also holds for star-forming galaxies to z ∼ 0.7, this implies that these scaling relations of galaxies will be minimally susceptible to progenitor biases owing to the evolving stellar populations, structures, and dynamics of galaxies through cosmic time.« less
  • We present Hubble Space Telescope NIC2 morphologies of a spectroscopic sample of massive galaxies at z approx 2.3 by extending our sample of 9 compact quiescent galaxies (r{sub e} approx 0.9 kpc) with 10 massive emission-line galaxies. The emission-line galaxies are classified by the nature of their ionized emission; there are six star-forming galaxies and four galaxies hosting an active galactic nucleus (AGN). The star-forming galaxies are the largest among the emission-line galaxies, with a median size of r{sub e} = 2.8 kpc. The three galaxies with the highest star formation rates (approx>100 M {sub sun} yr{sup -1}) have irregularmore » and clumpy morphologies. The AGN host galaxies are more similar to the compact quiescent galaxies in terms of their structures (r{sub e} approx 1.1 kpc) and spectral energy distributions. The total sample clearly separates into two classes in a color-mass diagram: the large star-forming galaxies that form the blue cloud, and the compact quiescent galaxies on the red sequence. However, it is unclear how or even if the two classes are evolutionary related. Three out of six massive star-forming galaxies have dense cores and thus may passively evolve into compact galaxies due to fading of outer star-forming regions. For these galaxies, a reverse scenario in which compact galaxies grow inside-out by star formation is also plausible. We do caution though that the sample is small. Nonetheless, it is evident that a Hubble sequence of massive galaxies with strongly correlated galaxy properties is already in place at z > 2.« less
  • We study the statistical distribution of satellites around star-forming and quiescent central galaxies at 1 < z < 3 using imaging from the FourStar Galaxy Evolution Survey and the Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey. The deep near-IR data select satellites down to log (M/M {sub ☉}) > 9 at z < 3. The radial satellite distribution around centrals is consistent with a projected Navarro-Frenk-White profile. Massive quiescent centrals, log (M/M {sub ☉}) > 10.78, have ∼2 times the number of satellites compared to star-forming centrals with a significance of 2.7σ even after accounting for differences in the centrals'more » stellar-mass distributions. We find no statistical difference in the satellite distributions of intermediate-mass quiescent and star-forming centrals, 10.48 < log (M/M {sub ☉}) < 10.78. Compared to the Guo et al. semi-analytic model, the excess number of satellites indicates that quiescent centrals have halo masses 0.3 dex larger than star-forming centrals, even when the stellar-mass distributions are fixed. We use a simple toy model that relates halo mass and quenching, which roughly reproduces the observed quenched fractions and the differences in halo mass between star-forming and quenched galaxies only if galaxies have a quenching probability that increases with halo mass from ∼0 for log (M{sub h} /M {sub ☉}) ∼ 11 to ∼1 for log (M{sub h} /M {sub ☉}) ∼ 13.5. A single halo-mass quenching threshold is unable to reproduce the quiescent fraction and satellite distribution of centrals. Therefore, while halo quenching may be an important mechanism, it is unlikely to be the only factor driving quenching. It remains unclear why a high fraction of centrals remain star-forming even in relatively massive halos.« less
  • We investigate star formation rates (SFRs) of quiescent galaxies at high redshift (0.3 < z < 2.5) using 3D-HST WFC3 grism spectroscopy and Spitzer mid-infrared data. We select quiescent galaxies on the basis of the widely used UVJ color-color criteria. Spectral energy distribution (SED) fitting (rest-frame optical and near-IR) indicates very low SFRs for quiescent galaxies (sSFR ∼ 10{sup –12} yr{sup –1}). However, SED fitting can miss star formation if it is hidden behind high dust obscuration and ionizing radiation is re-emitted in the mid-infrared. It is therefore fundamental to measure the dust-obscured SFRs with a mid-IR indicator. We stackmore » the MIPS 24 μm images of quiescent objects in five redshift bins centered on z = 0.5, 0.9, 1.2, 1.7, 2.2 and perform aperture photometry. Including direct 24 μm detections, we find sSFR ∼ 10{sup –11.9} × (1 + z){sup 4} yr{sup –1}. These values are higher than those indicated by SED fitting, but at each redshift they are 20-40 times lower than those of typical star-forming galaxies. The true SFRs of quiescent galaxies might be even lower, as we show that the mid-IR fluxes can be due to processes unrelated to ongoing star formation, such as cirrus dust heated by old stellar populations and circumstellar dust. Our measurements show that star formation quenching is very efficient at every redshift. The measured SFR values are at z > 1.5 marginally consistent with the ones expected from gas recycling (assuming that mass loss from evolved stars refuels star formation) and well below that at lower redshifts.« less