Detection of outflowing and extraplanar gas in disks in an assembling galaxy cluster at z = 0.37

Emily Freeland, Kim Vy H. Tran, Trevor Irwin, Lea Giordano, Amélie Saintonge, Anthony H. Gonzalez, Dennis Zaritsky, Dennis Just

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


We detect ionized gas characteristics indicative of winds in three disk-dominated galaxies that are members of a super-group at z = 0.37 that will merge to form a Coma-mass cluster. All three galaxies are IR luminous (L IR > 4 × 1010 L , SFR > 8 M yr-1) and lie outside the X-ray cores of the galaxy groups. We find that the most IR-luminous galaxy has strong blueshifted and redshifted emission lines with velocities of ∼ ± 200 km s -1 and a third, blueshifted (900 km s-1) component. This galaxy's line widths (Hβ, [OIII]λ5007, [NII], Hα) correspond to velocities of 100-1000 km s-1. We detect extraplanar gas in two of the three galaxies with SFR >8 M yr-1 whose orientations are approximately edge-on and which have integral field unit (IFU) spaxels off the stellar disk. IFU maps reveal that the extraplanar gas extends to rh ∼ 10kpc; [NII] and Hα line widths correspond to velocities of 200-400 km s-1 in the disk and decrease to ∼ 50-150 km s-1 above the disk. Multi-wavelength observations indicate that the emission is dominated by star formation. Including the most IR-luminous galaxy we find that 18% of supergroup members with SFR >8 M yr-1 show ionized gas characteristics indicative of outflows. This is a lower limit as showing that gas is outflowing in the remaining, moderately inclined, galaxies requires a non-trivial decoupling of contributions to the emission lines from rotational and turbulent motion. Ionized gas mass loss in these winds is ∼0.1 M yr-1 for each galaxy, although the winds are likely to entrain significantly larger amounts of mass in neutral and molecular gases.

Original languageEnglish (US)
Article numberL34
JournalAstrophysical Journal Letters
Issue number2
StatePublished - Dec 1 2011


  • galaxies: clusters: general
  • galaxies: evolution
  • galaxies: groups: general
  • galaxies: starburst

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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