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


Freeland, E; Tran, K V H; Irwin, T; Giordano, L; Saintonge, A; Gonzalez, A H; Zaritsky, D; Just, D (2011). Detection of outflowing and extraplanar gas in disks in an assembling galaxy cluster at z = 0.37. Astrophysical Journal Letters, 742(2):L34.

Abstract

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 sun, SFR > 8 M sun 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, [O III]λ5007, [N II], Hα) correspond to velocities of 100-1000 km s-1. We detect extraplanar gas in two of the three galaxies with SFR >8 M sun 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 ~ 10 kpc [N II] 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 sun 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 sun yr-1 for each galaxy, although the winds are likely to entrain significantly larger amounts of mass in neutral and molecular gases.

Abstract

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 sun, SFR > 8 M sun 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, [O III]λ5007, [N II], Hα) correspond to velocities of 100-1000 km s-1. We detect extraplanar gas in two of the three galaxies with SFR >8 M sun 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 ~ 10 kpc [N II] 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 sun 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 sun yr-1 for each galaxy, although the winds are likely to entrain significantly larger amounts of mass in neutral and molecular gases.

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Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Institute for Computational Science
Dewey Decimal Classification:530 Physics
Language:English
Date:December 2011
Deposited On:18 Feb 2012 13:05
Last Modified:21 Nov 2017 15:45
Publisher:Institute of Physics Publishing
ISSN:0004-637X (P) 1538-4357 (E)
Publisher DOI:https://doi.org/10.1088/2041-8205/742/2/L34
Related URLs:http://arxiv.org/abs/1111.0289

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