科研之友
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摘要
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 x 10(10) L-circle dot, SFR > 8 M-circle dot 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 similar to +/- 200 km s(-1) and a third, blueshifted (similar to 900 km s(-1)) component. This galaxy's line widths (H beta, [O III]lambda 5007, [N II], H alpha) correspond to velocities of 100-1000 km s(-1). We detect extraplanar gas in two of the three galaxies with SFR > 8 M-circle dot 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 r(h) similar to 10 kpc; [N II] and H alpha line widths correspond to velocities of similar to 200-400 km s(-1) in the disk and decrease to similar 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-circle dot 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 similar to 0.1 M-circle dot yr(-1) for each galaxy, although the winds are likely to entrain significantly larger amounts of mass in neutral and molecular gases.
- 出版日期2011-12-1
