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arXiv 1609.03040astro-ph.GA
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Spitzer/IRS星系UV ~ 22 $μ$ m光谱能量分布的物理性质

The physical properties of Spitzer/IRS galaxies derived from their UV to 22 $μ$m spectral energy distribution

Marina Vika, Laure Ciesla, Vassilis Charmandaris, Emmanuel M. Xilouris, Vianney Lebouteiller

摘要:

我们提供了完整的CASSIS中包含的所有星系的基本综合物理性质与可用的宽带测光从UV到22 $μ$ m。为了研究CASSIS中每个星系的SED,我们从现有的公共调查中收集了14个波长的光度测量结果,从而构建了红移范围0<z<2.5的1,146个星系的最终样本。的SED建模与CIGALE代码依赖于被吸收的恒星和尘埃排放之间的能量平衡,同时考虑到可能的贡献,由于活动星系核的存在。我们将星系分为三组,一个低红移,一个中红移和一个高红移,并发现绝大多数的斯皮策/IRS星系是恒星形成和谎言或以上的恒星形成MS相应的红移。此外,z<0.1的Spitzer/IRS星系的辐射主要由恒星形成活动所支配,中红移区域的星系是恒星形成星系和活动星系核的混合体,而z<0.5的星系中有一半表现出中等或高活动星系核活动。此外,利用静止坐标系NUV-r色,Sérsic指数,光学OIII和NII发射线,我们探索这些星系的性质,通过调查它们的结构以及它们的恒星形成和活动星系核活动。使用彩色星等图,我们证实,97%的星系的红移小于0.5经历了最近的恒星形成插曲。对于一个子样本的星系可用的结构信息和红移小于0.3,我们发现,早型星系被放置在MS下方,而晚型星系被发现的MS预期。最后,对于所有z<0.5的星系和可用的光谱线测量,我们发现,具有高活动星系核光度的星系,如CIGALE计算的,最有可能被归类为复合星系核或活动星系核的光学谱线。

英文摘要:

We provide the basic integrated physical properties of all the galaxies contained in the full CASSIS with available broad-band photometry from UV to 22 $μ$m. We have collected photometric measurements in 14 wavelengths from available public surveys in order to study the SED of each galaxy in CASSIS, thus constructing a final sample of 1,146 galaxies in the redshift range 0<z<2.5. The SEDs are modelled with the CIGALE code which relies on the energy balance between the absorbed stellar and the dust emission while taking into account the possible contribution due to the presence of an AGN. We split the galaxies in three groups, a low-redshift, a mid-redshift and a high-redshift and find that the vast majority of the Spitzer/IRS galaxies are star-forming and lie on or above the star-forming MS of the corresponding redshift. Moreover, the emission of Spitzer/IRS galaxies with z<0.1 is mostly dominated by star-formation, galaxies in the mid-redshift bin are a mixture of star forming and AGN galaxies, while half of the galaxies with z<0.5 show moderate or high AGN activity. Additionally, using rest-frame NUV-r colour, Sérsic indices, optical OIII and NII emission lines we explore the nature of these galaxies by investigating their structure as well as their star-formation and AGN activity. Using a colour magnitude diagram we confirm that 97% of the galaxies with redshift smaller than 0.5 have experienced a recent star-formation episode. For a sub-sample of galaxies with available structural information and redshift smaller than 0.3 we find that early-type galaxies are placed below the MS, while late-type galaxies are found on the MS as expected. Finally, for all the galaxies with z<0.5 and available optical spectral line measurements we find that galaxies with high AGN luminosity, as calculated by CIGALE, are most likely to be classified as composite or AGNs by optical spectral lines.

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