Dust Properties of Clumpy Disc Galaxies at z~1.3 with Herschel-SPIRE

Abstract

We present the far-infrared derived dust properties from Herschel SPIRE of the WiggleZ kinematic sample of 13 star-forming galaxies at z~1.3, with existing ancillary ~kpc resolution integral field spectroscopy. We detect 3 galaxies individually and place limits on the remainder by stacking. The detected galaxies, two clumpy discs and one merger, have cold dust temperatures of ~26 K and have infrared luminosities of ~1.2x10^12 solar luminosities, determined by modified blackbody fitting. The two detected disc galaxies have the largest H\alpha surface areas of the sample and have the reddest ultraviolet to near-infrared spectral energy distributions. The likely source of the infrared luminosity in these objects is dust heated by the interstellar radiation field and young stellar emission from the clumps within the discs. The source of infrared luminosity for the merger is likely a dust heated by a starburst resulting from the merger. The WiggleZ detections are among the coldest and lowest luminosity individual objects detected in the far-infrared at z>1. When combining the kinematic data, we find that none of the compact galaxies nor the 'dispersion dominated' galaxies of the WiggleZ kinematic sample are detected, implying that they have warmer dust temperatures. The compact objects show the highest H\alpha velocity dispersions in the sample, in qualitative agreement with bulge formation models. These far-infrared results strengthen the interpretation that the majority of galaxies in this sample constitute different stages in clumpy disc formation as presented from ancillary kinematic analysis.