An Explanation for the Observed Weak Size Evolution of Disk Galaxies

By R. Somerville, M. Barden, Hans-Walter Rix, Eric F. Bell, S. Beckwith, A. Borch, J. Caldwell, B. Haeussler, Catherine Heymans, K. Jahnke and 7 more. 2006

142 citations recorded by the source corpus.

Surveys of distant galaxies with the Hubble Space Telescope and from the ground have shown that there is only mild evolution in the relationship between radial size and stellar mass for galactic disks from z ∼ 1 to the present day. Using a sample of nearby disk-dominated galaxies from the Sloan Digital Sky Survey (SDSS) and high-redshift data from the GEMS (Galaxy Evolution from Morphology and SEDs) survey, we investigate whether this result is consistent with theoretical expectations within the hierarchical paradigm of structure formation. The relationship between virial radius and mass for dark matter halos in the ΛCDM model evolves by about a factor of 2 over this interval. However, N-body simulations have shown that halos of a given mass have less centrally concentrated mass profiles at high redshift. When we compute the expected disk size-stellar mass distribution, accounting for this evolution in the internal structure of dark matter halos and the adiabatic contraction of the dark matter by the self-gravity of the collapsing baryons, we find that the predicted evolution in the mean size at fixed stellar mass since z ∼ 1 is about 15%-20%, in good agreement with the observational constraints from GEMS. At redshift z ∼ 2, the model predicts that disks at fixed stellar mass were on average only 60% as large as they are today. Similarly, we predict that the rotation velocity at a given stellar mass (essentially the zero point of the Tully-Fisher relation) is only about 10% larger at z ∼ 1 (20% at z ∼ 2) than at the present day.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/0e7ec0445ce4251547e7d05a10c85d420040998d

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In Astronomy and Astrophysics

1. P. Hopkins
2. L. Hernquist
3. R. Dav'e
4. R. Somerville
5. A. Dekel
6. Volker Springel
7. T. Naab
8. D. Keres̆

In Instrumentation

1. P. Hopkins
2. L. Hernquist
3. A. Dekel
4. R. Somerville
5. R. Dav'e
6. T. Naab
7. Thomas J. Cox
8. Volker Springel

Citations in the corpus

• The origin of discs and spheroids in simulated galaxies (2011, background): “This consensus view has been broadly implemented in semianalytic models of galaxy formation, where the properties of galaxies are deduced directly from the physical properties and assembly history of their surrounding haloes (see e.g. Bower et al. 2006; Croton et al. 2006; Somerville et al. 2008).”
• Structure and Star Formation in Galaxies out to z = 3: Evidence for Surface Density Dependent Evolution and Upsizing (2008, background): “More complex models find generally weaker evolution (e.g., Somerville et al. 2008).”
• CANDELS: THE COSMIC ASSEMBLY NEAR-INFRARED DEEP EXTRAGALACTIC LEGACY SURVEY (2011, unknown): “Major mergers occupy a central role in hierarchical theories of galaxy formation, and are a favorite mechanism for building spheroids, triggering BH growth and igniting starbursts (e.g., Sanders et al. 1988; Hopkins et al. 2006; Somerville et al. 2008b).”
• Compact high-redshift galaxies are the cores of the most massive present-day spheroids (2009, background): “…this apparent evolution must be particular to this class of galaxies: disc E-mail: phopkins@astro.berkeley.edu †Canada Research Chair in Astrophysics. galaxies are not similarly compact at high redshift (Ferguson et al. 2004; Ravindranath et al. 2004; Barden et al. 2005; Somerville et al. 2008).”
• A DIVERSITY OF PROGENITORS AND HISTORIES FOR ISOLATED SPIRAL GALAXIES (2012, methodology): “This idea is supported by observations (Barden et al. 2005; Maier et al. 2009), and it has already been seen in other simulations (Brooks et al. 2011) and semi-analytic models (Somerville et al. 2008; Firmani & Avila-Reese 2009; Dutton et al. 2010).”
• THE SINS SURVEY: MODELING THE DYNAMICS OF z ∼ 2 GALAXIES AND THE HIGH-z TULLY–FISHER RELATION (2009, background): “…with galaxy evolution models Interestingly, the amount of observed evolution in our sample is consistent with the factor ∼ 1.25 of increased velocity for a given stellar mass predicted by Somerville et al. (2008) in their semi-analytic formation model of a disk with M∗ = 6×1010 M⊙ at this redshift.”
• Discriminating Between the Physical Processes that Drive Spheroid Size Evolution (2009, background): “…evolution must be particular to this class of galaxies: disc galaxies do not become similarly compact at high redshift (Buitrago et al. 2008; Somerville et al. 2008, and references therein).1 In addition, these high-redshift populations have been linked to observed submillimeter galaxies,…”
• MERGERS IN ΛCDM: UNCERTAINTIES IN THEORETICAL PREDICTIONS AND INTERPRETATIONS OF THE MERGER RATE (2010, methodology): “Incontrast, the semi-analytic models of Somerville et al. (2008a) and Khochfar & Silk (2009) predict little discrepancy between theMgal(Mhalo) relations of satellites and centrals.”
• THE SPATIAL STRUCTURE OF MONO-ABUNDANCE SUB-POPULATIONS OF THE MILKY WAY DISK (2011, background): “Yet, direct observational evidence for this picture is scant (e.g., Dalcanton et al. 1997; Somerville et al. 2008; Wang et al. 2011), and forming realistic disks within the ΛCDM paradigm remains challenging (e.g., Abadi et al. 2003; Scannapieco et al. 2009; Guedes et al. 2011).”
• On the origin of the galaxy star‐formation‐rate sequence: evolution and scatter (2009, background): “The weak evolution at low redshifts is due to the evolution in the halo concentration (see Somerville et al. 2008).”
• THE SINS SURVEY OF z ∼ 2 GALAXY KINEMATICS: PROPERTIES OF THE GIANT STAR-FORMING CLUMPS (2010, background): “…the intense star-forming activity in the giant clumps is reflected in local enhancements in metallicity, and whether there are abundance differences between the central and outer parts of the galaxies because of the expected inside-out evolution of the galaxies (e.g., Somerville et al. 2008).”
• The Milky Way’s stellar disk (2013, methodology): “This approach performed well in explaining the overall properties of the present-day galaxy disk population and also its redshift evolution (e.g., Somerville et al. 2008).”
• A White Paper on keV sterile neutrino Dark Matter (2016, methodology): “These are compared with predictions from a WDM model [474] and from different CDM models in the literature: the MORGANA model [476, grey dot-dashed line]; the Millenium-based SAM [477, blue short-dashed line]; the [478] code (purple dashed line); the Millenium-based model [438], petrol solid line (t”
• 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): “Size determinations, however, can be affected by various factors, and reconciling observed sizes with theoretical predictions remains a challenge (e.g., Dutton et al. 2007; Dutton & van den Bosch 2009b; Dutton et al. 2011; Somerville et al. 2008; Sales et al. 2009; Burkert et al. 2010).”
• Galaxy formation theory (2010, background): “Recent years have seen numerous implementations of detailemodels of galaxy formation incorporating AGN feedback (Scannapieco and Oh 2004; Croton et al. 2006; Boweret al. 2006; Cattaneo et al. 2006; Somerville et al. 2008b).”
• The effects of gas on morphological transformation in mergers: implications for bulge and disc demographics (2009, methodology): “…in mergers, allowing for the efficiency of merger-induced bulge formation to be adjusted, still find the same difficulty even with these degrees of freedom (Somerville, Primack & Faber 2001; Khochfar & Burkert 2003; Granato et al. 2004; Croton et al. 2006; Somerville et al. 2008a, hereafter S08).”