GAMA/H-ATLAS: The Dust Opacity - Stellar Mass Surface Density Relation for Spiral Galaxies
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… 展开作者
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, τ^f_B, and the stellar mass surface density, μ_{*}, of nearby (z < 0.13) spiral galaxies: log(τ^f_B) = 1.12(+-0.11)log(μ_{*}/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 μ_{*} 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 τ^f_B-μ_{*} 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 τ^f_B-μ_{*} 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 μ_{*}, 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.
H-ATLAS/GAMA: Quantifying the Morphological Evolution of the Galaxy Population Using Cosmic Calorimetry
利用Herschel天体物理太赫兹大面积巡天和星系与质量组装项目的结果，我们表明，对于质量大于约1.0e8太阳质量的星系，本机宇宙中51%的恒星质量密度位于早型星系中（ETG：Sersic n > 2.5），而89%的恒星质量密度产生率发生在晚型星系（LTG：Sersic n < 2.5）。从这个零红移的基准，我们已经使用了量热技术来量化的重要性的形态转变的星系在宇宙的历史。河外背景辐射包含了大爆炸以来恒星核聚变产生的全部能量。通过使用赫歇尔空间天文台的最深远红外调查和哈勃太空望远镜（HST）的深近红外/光学调查将这种背景辐射分解为单个星系，并使用来自HST图像的这些星系的Sersic指数的测量值，我们估计在宇宙历史上形成的恒星质量密度中约有83%发生在LTG中。这与现今LTG中恒星质量密度的比例之间的差异意味着在大多数恒星形成之后，LTG必须有一个主要的转变。
