Astronomy Seminar

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I will present high resolution (0.03 arcsec) rest-frame 160 micron continuum maps of four z~4.5 sub-mm galaxies (SMGs) selected from the ALMA-LESS and ALMA-UDS surveys. These cycle 3 observations resolve the gas and dust within the ISM of these galaxies on 0.2-1 kpc scales. The data reveal an apparent range of morphologies. Though the continuum morphologies appear to be: smooth and compact or extended and ‘clumpy’, comparison with simulations reveal that all four sources are consistent with exponential discs. From the morphologies and dynamics of the gas and dust, I will show that these SMGs are most likely to contain dust discs which are smooth on scales of ~200pc. These four SMGs are also bright [CII] emitters and by considering the L([CII])/\L(FIR) ratio as a function of the star-formation rate surface density I will revisit the [CII] deficit, which these measurement suggest, is consistent with local processes. I will present some of the physical drivers that may be responsible for this trend and can give rise to the properties found in the densest regions of SMGs.