The sins/zC-sinf survey of z ∼ 2 galaxy kinematics: The nature of dispersion-dominated galaxies

Sarah F. Newman, Reinhard Genzel, Natascha M. Förster Schreiber, Kristen Shapiro Griffin, Chiara Mancini, Simon J. Lilly, Alvio Renzini, Nicolas Bouché, Andreas Burkert, Peter Buschkamp, C. Marcella Carollo, Giovanni Cresci, Ric Davies, Frank Eisenhauer, Shy Genel, Erin K.S. Hicks, Jaron Kurk, Dieter Lutz, Thorsten Naab, Yingjie PengAmiel Sternberg, Linda J. Tacconi, Stijn Wuyts, Gianni Zamorani, Daniela Vergani

Research output: Contribution to journalArticlepeer-review


We analyze the spectra, spatial distributions, and kinematics of Hα, [N II], and [S II] emission in a sample of 38, z ∼ 2.2 UV/optically selected star-forming galaxies (SFGs) from the SINS and zC-SINF surveys, 34 of which were observed in the adaptive optics mode of SINFONI and 30 of those contain data presented for the first time here. This is supplemented by kinematic data from 43 z ∼ 1-2.5 galaxies from the literature. None of these 81 galaxies is an obvious major merger. We find that the kinematic classification of high-z SFGs as "dispersion dominated" or "rotation dominated" correlates most strongly with their intrinsic sizes. Smaller galaxies are more likely "dispersion-dominated" for two main reasons: (1) the rotation velocity scales linearly with galaxy size but intrinsic velocity dispersion does not depend on size or may even increase in smaller galaxies, and as such, their ratio is systematically lower for smaller galaxies, and (2) beam smearing strongly decreases large-scale velocity gradients and increases observed dispersion much more for galaxies with sizes at or below the resolution. Dispersion-dominated SFGs may thus have intrinsic properties similar to "rotation-dominated" SFGs, but are primarily more compact, lower mass, less metal enriched, and may have higher gas fractions, plausibly because they represent an earlier evolutionary state.

Original languageEnglish
Article number104
JournalAstrophysical Journal
Issue number2
StatePublished - 20 Apr 2013


  • galaxies: evolution
  • galaxies: high-redshift
  • infrared: galaxies

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


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