Compact high-redshift galaxies are the cores of the most massive present-day spheroids

By P. Hopkins, K. Bundy, N. Murray, E. Quataert, Tod R. Lauer, C. Berkeley, Cita, Noao. 2009

211 citations recorded by the source corpus.

Observations suggest that the effective radii of high-redshift massive spheroids are as much as a factor of ~6 smaller than low-redshift galaxies of comparable mass. Given the apparent absence of low-redshift counterparts, this has often been interpreted as indicating that the high-density, compact red galaxies must be 'puffed up' by some mechanism. We compare the ensemble of high-redshift observations with large samples of well-observed, low-redshift ellipticals. At the same physical radii, the stellar surface mass densities of low- and high-redshift systems are comparable. Moreover, the abundance of high surface density material at low redshift is comparable to or larger than that observed at z > 1-2, consistent with the continuous buildup of spheroids over this time. The entire population of compact, high-redshift red galaxies may be the progenitors of the high-density cores of present-day ellipticals, with no need for a decrease in stellar density from z = 2 to 0. The primary difference between low- and high-redshift systems is thus the observed low-density material at large radii in low-redshift spheroids (rather than the high-density material in high-redshift spheroids). Such low-density material may either (1) assemble at z 2. Mock observations of low-redshift massive systems suggest that the amount of low-density material at high redshifts is indeed significantly less than that at z = 0. However, deeper observations will be important in constraining the exact amount (or lack thereof) and distribution of this material, and how it builds up with redshift. We show that, without deep observations, the full extent of such material even at low redshifts can be difficult to determine, in particular if the mass profile is not exactly a single Sersic profile. We discuss the implications of our results for physical models of galaxy evolution.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/d517812508a3474970fde2f5d71ec1011479108f

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Citations in the corpus

Structural and Star-forming Relations since z ∼ 3: Connecting Compact Star-forming and Quiescent Galaxies (2015, background): “The leading explanation is that quiescent galaxies experience a large increase in size compared to the mass growth due to minor mergers (i.e., accretion of smaller satellite galaxies; Bezanson et al. 2009; Hopkins et al. 2009; Oser et al. 2012).”
FORMING COMPACT MASSIVE GALAXIES (2015, methodology): “…to reproduce the broad characteristics of compact massive galax- 2 ies, either by mergers that are accompanied by a strong central star burst (e.g., Hopkins et al. 2009b; Wuyts et al. 2010; Wellons et al. 2015), by in-situ formation from highly efficient gas cooling (Naab et al. 2009; Wellons et…”
THE DEPENDENCE OF QUENCHING UPON THE INNER STRUCTURE OF GALAXIES AT 0.5 ⩽ z < 0.8 IN THE DEEP2/AEGIS SURVEY (2012, background): “Merger Model Major mergers33 have been linked to the formation of spheroids since Toomre & Toomre (1972), with considerable work in the years since (see Hopkins et al. 2009a and references therein).”
CONSTRAINTS ON THE ASSEMBLY AND DYNAMICS OF GALAXIES. I. DETAILED REST-FRAME OPTICAL MORPHOLOGIES ON KILOPARSEC SCALE OF z ∼ 2 STAR-FORMING GALAXIES (2010, background): “…the formation and evolution of such compact, quiescent galaxies at highz is the basis of much ongoing observational and theoretical work (e.g., Trujillo et al. 2007; Cimatti et al. 2008; van der Wel et al. 2008; Damjanov et al. 2009; Hopkins et al. 2009; Mancini et al. 2010; Wuyts et al. 2010).”
The effect of mass ratio on the morphology and time-scales of disc galaxy mergers: Effect of mass ratio on merger morphology (2009, background): “Most previous theoretical studies of minor mergers have focused on the structures of the merger remnants (e.g. Hopkins et al. 2009; Naab et al. 2009; Robertson et al 2006; Bournaud, Jog, & Combes et al. 2004; Johnston et al. 1996) or spanned a very limited range of parameter space (Conselice 2006).”
Evolution of density profiles in high-z galaxies: compaction and quenching inside-out (2015, background): “Often, this trend has been entirely ascribed to the physical growth of individual galaxies, where massive quiescent galaxies grow through accretion of smaller galaxies in minor gas-poor mergers (e.g. Naab et al. 2009; Hopkins et al. 2009; Nipoti et al. 2009; Feldmann et al. 2010; Oser et al. 2012).”
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).”
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SUPERDENSE MASSIVE GALAXIES IN WINGS LOCAL CLUSTERS (2009, background): “…seem 1 As far asphysical densitiesare concerned, the galaxies under investigation here are thought not to be extreme (see,e.g. Bezanson et al. 2009; Hopkins et al. 2009a) anyway larger (by a factor of∼ 2) than the most distant z≥ 2 and massive M∗ ≥ 1011M⊙ galaxies recently discovered…”
AN ULTRA-DEEP NEAR-INFRARED SPECTRUM OF A COMPACT QUIESCENT GALAXY AT z = 2.2 (2009, background): “For example, subsequent merging is expected to result in central dissipational starbursts (e.g., Hopkins et al. 2009a).”
Galaxy And Mass Assembly (GAMA): mass–size relations of z < 0.1 galaxies subdivided by Sérsic index, colour and morphology (2014, background): “Non-physical and systematic effects may include various selection biases, as well as erroneous estimations of mass and size (see e.g. Hopkins et al. 2009 and references therein).”
A LARGE POPULATION OF MASSIVE COMPACT POST-STARBURST GALAXIES AT z > 1: IMPLICATIONS FOR THE SIZE EVOLUTION AND QUENCHING MECHANISM OF QUIESCENT GALAXIES (2011, background): “The continuous transformation of these larger, star-forming galaxies at later times could be responsible for part of the size growth of the red sequence (e.g., van Dokkum et al. 2008; van der Wel et al. 2009a; Hopkins et al. 2009; Szomoru et al. 2011).”
Detection of HCN, HCO+, and HNC in the Mrk 231 molecular outflow. Dense molecular gas in the AGN wind (2011, background): “Powerful outflows have been proposed to regulate both star-formation and the SMBH growth through negative feedback in young galaxies (e.g. Hopkins et al. 2009; Murray et al. 2005).”
Early type galaxies have been the predominant morphological class for massive galaxies since only z~1 (2011, background): “These wings, however, seem to disappear at higher and higher redshifts (see Table 1 or Figure 3) just leaving the inner (core) region of the massive galaxies (Bezanzon et al. 2009; Hopkins et al. 2009; van Dokkum et al. 2010; Carrasco, Conselice & Trujillo 2010).”
THE GROWTH OF MASSIVE GALAXIES SINCE z = 2 (2009, background): “As noted by Franx et al. (2008); Hopkins et al. (2009c); Bezanson et al. (2009); Cenarro & Trujillo (2009) and others, a proper comparison would consider all progenitors, not just the quiescent galaxies, and explicitly take mass evolutioninto account.”
NEWLY QUENCHED GALAXIES AS THE CAUSE FOR THE APPARENT EVOLUTION IN AVERAGE SIZE OF THE POPULATION (2013, background): “…Q-ETGs maintain a nearly constant mass within their innermost few kpcs, and gradually grow inside-out, building up extended stellar envelopes/halos around such compact, dense cores (e.g., Cimatti et al. 2008; Hopkins et al. 2009, 2010; Taylor et al. 2010; Feldmann et al. 2010; Szomoru et al. 2011).”
Coevolution (Or Not) of Supermassive Black Holes and Host Galaxies (2013, methodology): “They suggest that and (e. g.) Hopkins et al. (2009) model how extra-light ellipticals form in wet mergers, such that the main body of the galaxy is the scrambled-up remnant of the pre-merger disk and bulge stars and the extra-light component is manufactured by a starburst during the merger.”
Families of dynamically hot stellar systems over 10 orders of magnitude in mass (2011, background): “The underestimation of the profile shape index n can also lead to a wrong determination of the effective radius Reff (see Hopkins et al. 2009).”
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, background): “…mass doubling happens via small satellites as mostly expected from the shape of the Schechter (1976) mass function, the radius will increase by a factor of 4 and the dispersion will be twice smaller (Bezanson et al. 2009; Hopkins et al. 2009a; Naab, Johansson & Ostriker 2009; Hilz et al. 2012).”