Radial distribution of dust, stars, gas, and star-formation rate in DustPedia face-on galaxies
Radial distribution of dust, stars, gas, and star-formation rate in DustPedia face-on galaxies
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DOI：
10.1051/0004-6361/201731020
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发表时间：
2017-06
影响因子：
6.5
通讯作者：
V. Casasola;L. Cassara';S. Bianchi;S. Verstocken;E. Xilouris;L. Magrini;M. Smith;I. D. Looze;M. Galametz;S. Madden;M. Baes;C. Clark;J. Davies;P. D. Vis;R. Evans;J. Fritz;F. Galliano;A. Jones;A. Mosenkov;S. Viaene;N. Y. INAF-Arcetri;National Observatory of Athens;G. University;Cardiff University;University College London;Laboratoire Aim;C. P. Diderot;Campus Morelia;I. D. Spatiale;Cnrs;U. Paris-sud;U. Paris-Saclay
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文献类型：
--
作者：
V. Casasola;L. Cassara';S. Bianchi;S. Verstocken;E. Xilouris;L. Magrini;M. Smith;I. D. Looze;M. Galametz;S. Madden;M. Baes;C. Clark;J. Davies;P. D. Vis;R. Evans;J. Fritz;F. Galliano;A. Jones;A. Mosenkov;S. Viaene;N. Y. INAF-Arcetri;National Observatory of Athens;G. University;Cardiff University;University College London;Laboratoire Aim;C. P. Diderot;Campus Morelia;I. D. Spatiale;Cnrs;U. Paris-sud;U. Paris-Saclay
目标。这项工作的目的是表征尘埃、恒星、气体和恒星形成率(SFR)的径向分布，这些子样本是从DustPedia样本中提取的18个面对面的螺旋星系。方法：研究方法。这项研究是通过利用多波长DustPedia数据库进行的，从紫外线(UV)到亚毫米波段，以及文献中提供的分子(12Co)和原子(Hi)气体图和金属丰度信息。我们用指数曲线拟合了尘埃和恒星示踪剂的表面亮度分布，尘埃、恒星、分子气体和总气体的质量表面密度分布，以及SFR的表面密度分布，并得出了它们的标尺长度。我们还发展了一种利用尘埃和气体质量剖面来求解每个星系的CO-to-H2转换因子(αCO)的方法。结果。虽然每个星系都有自己独特的行为，但我们发现了一个指数尺度的共同趋势--长度与波长的关系。平均而言，归一化到B波段25毫克/弧2半径的标尺长度从UV减小到70μm，从0.4减小到0.2，然后在500微米处增加到~0.3。主要结果是，平均而言，尘埃质量面密度尺度长度大约是由红外光谱数据和3.6μm表面亮度得到的恒星尺度长度的1.8倍，而接近于紫外光中的尺度长度。我们发现尺度长度对哈勃阶段T有轻微的依赖关系：赫歇尔带的尺度长度和3.6μm尺度长度由早到晚呈增加趋势，70μm处的尺度长度趋于小于较长亚毫米波长的尺度长度，长亚毫米波长与70μm的比例随T的增加而减小。我们的αCO测量在(0.3−9)M⊙PC-2(K Km S-1)-1的范围内，几乎不变，使用固定的尘气比质量或依赖于金属丰度梯度的尘气比。
Aims. The purpose of this work is the characterization of the radial distribution of dust, stars, gas, and star-formation rate (SFR) in a sub-sample of 18 face-on spiral galaxies extracted from the DustPedia sample. Methods. This study is performed by exploiting the multi-wavelength DustPedia database, from ultraviolet (UV) to sub-millimeter bands, in addition to molecular (12CO) and atomic (Hi) gas maps and metallicity abundance information available in the literature. We fitted the surface-brightness profiles of the tracers of dust and stars, the mass surface-density profiles of dust, stars, molecular gas, and total gas, and the SFR surface-density profiles with an exponential curve and derived their scale-lengths. We also developed a method to solve for the CO-to-H2 conversion factor (αCO) per galaxy by using dust- and gas-mass profiles. Results. Although each galaxy has its own peculiar behavior, we identified a common trend of the exponential scale-lengths versus wavelength. On average, the scale-lengths normalized to the B-band 25 mag/arcsec2 radius decrease from UV to 70 μm, from 0.4 to 0.2, and then increase back up to ~0.3 at 500 microns. The main result is that, on average, the dust-mass surface-density scale-length is about 1.8 times the stellar one derived from IRAC data and the 3.6 μm surface brightness, and close to that in the UV. We found a mild dependence of the scale-lengths on the Hubble stage T: the scale-lengths of the Herschel bands and the 3.6 μm scale-length tend to increase from earlier to later types, the scale-length at 70 μm tends to be smaller than that at longer sub-mm wavelength with ratios between longer sub-mm wavelengths and 70 μm that decrease with increasing T. The scale-length ratio of SFR and stars shows a weak increasing trend towards later types. Our αCO determinations are in the range (0.3−9) M⊙ pc-2 (K km s-1)-1, almost invariant by using a fixed dust-to-gas ratio mass (DGR) or a DGR depending on metallicity gradient.