The SINS/zC-SINF survey of z 2 galaxy kinematics: Outflow properties

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, Daniela Vergani, Stijn Wuyts, Gianni Zamorani

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Using SINFONI Hα, [N II], and [S II] AO data of 27 z 2 star-forming galaxies (SFGs) from the SINS and zC-SINF surveys, we explore the dependence of outflow strength (via the broad flux fraction) on various galaxy parameters. For galaxies that have evidence for strong outflows, we find that the broad emission is spatially extended to at least the half-light radius (a few kpc). Decomposition of the [S II] doublet into broad and narrow components suggests that this outflowing gas probably has a density of 10-100 cm-3, less than that of the star-forming gas (600 cm-3). There is a strong correlation of the Hα broad flux fraction with the star formation surface density of the galaxy, with an apparent threshold for strong outflows occurring at 1 M yr-1 kpc-2. Above this threshold, we find that SFGs with log m * > 10 have similar or perhaps greater wind mass-loading factors (η = /SFR) and faster outflow velocities than lower mass SFGs, suggesting that the majority of outflowing gas at z 2 may derive from high-mass SFGs. The mass-loading factor is also correlated with the star formation rate (SFR), galaxy size, and inclination, such that smaller, more star-forming, and face-on galaxies launch more powerful outflows. We propose that the observed threshold for strong outflows and the observed mass loading of these winds can be explained by a simple model wherein break-out of winds is governed by pressure balance in the disk.

Original languageEnglish
Article number43
JournalAstrophysical Journal
Volume761
Issue number1
DOIs
StatePublished - 10 Dec 2012

Keywords

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

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