M. W. Grootes, R. J. Tuffs, C. C. Popescu, B. Pastrav, E. Andrae, M. Gunawardhana, L. S. Kelvin, J. Liske, M. Seibert, E. N. Taylor, A. W. Graham, M. Baes, I. K. Baldry, N. Bourne, S. Brough, A. Cooray, A. Dariush, G. De Zotti, S. P. Driver, L. Dunne, H. Gomez, A. M. Hopkins, R. Hopwood, M. Jarvis, J. Loveday, S. Maddox, B. F. Madore, M. J. Michałowski, P. Norberg, H. R. Parkinson, M. Prescott, A. S. G. Robotham, D. J. B. Smith, D. Thomas, E. Valiante
We report the discovery of a well-defined correlation between B-band face-on central optical depth due to dust, \tau^f_B, and the stellar mass surface density, \mu_{*}, of nearby (z < 0.13) spiral galaxies: log(\tau^f_B) = 1.12(+-0.11)log(\mu_{*}/M_sol kpc^2)-8.6(+-0.8). This relation was derived from a sample of spiral galaxies taken from the Galaxy and Mass Assembly (GAMA) survey and detected in the FIR/submm in the Herschel-ATLAS survey. Using a quantitative analysis of the NUV attenuation-inclination relation for complete samples of GAMA spirals categorized according to \mu_{*} we demonstrate that this correlation can be used to statistically correct for dust attenuation purely on the basis of optical photometry and S'ersic-profile morphological fits. Considered together with previously established empirical relationships between stellar mass, metallicity and gas mass, the near linearity and high constant of proportionality of the \tau^f_B-\mu_{*} relation disfavors a stellar origin for the bulk of refractory grains in spiral galaxies, instead being consistent with the existence of a ubiquitous and very rapid mechanism for the growth of dust in the ISM. We use the \tau^f_B-\mu_{*} relation in conjunction with the radiation transfer model for spiral galaxies of Popescu & Tuffs (2011) to derive intrinsic scaling relations between specific star formation rate (sSFR), stellar mass, and \mu_{*}, in which the attenuation of the UV light used to measure the SFR is corrected on an object-to-object basis. A marked reduction in scatter in these relations is achieved which is demonstrably due to correction of both the inclination-dependent and face-on components of attenuation. Our results are consistent with a picture of spiral galaxies in which most of the submm emission originates from grains residing in translucent structures, exposed to UV in the diffuse interstellar radiation field.
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http://arxiv.org/abs/1302.1379
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