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arXiv 1209.5844astro-ph.GA
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从AKARI和GALEX看局域星系的恒星形成和尘埃消光性质

Star Formation and Dust Extinction Properties of Local Galaxies as seen from AKARI and GALEX

A. Sakurai, T. T. Takeuchi, F. -T. Yuan, V. Buat, D. Burgarella

摘要:

准确估计星系的恒星形成相关性质对于理解星系的演化至关重要。在星系中,由最近形成的大质量恒星发出的紫外线(UV)被尘埃衰减,尘埃也是由恒星形成(SF)活动产生的,并以中红外和远红外(IR)波长重新发射。在这项研究中,我们调查的恒星形成率(SFR)和尘埃消光使用紫外和红外数据。我们选择了在AKARI FIS 90 um检测到的本地星系,并与IRAS IIFSCz 60 um选择目录相匹配。我们从GALEX图像测量FUV和NUV通量密度。我们用AKARI的四个波段研究了本星系的SF和消光。然后,我们计算了FUV和总红外光度,得到了SF光度、L_{SF}、与恒星形成活动相关的总光度和SFR。我们发现在大多数星系中,L_{SF}是由L_{dust}主导的。我们还发现,具有较高的SF活动的星系有较高的分数,其SF隐藏的尘埃。事实上,SFR>20 M_{sun} /yr的星系的SF几乎完全被尘埃所掩盖。由于使用了来自AKARI和GALEX所有天空调查的更大的物体样本,我们的结果相对于以前发表的作品具有更高的精度。

英文摘要:

An accurate estimation of the star formation-related properties of galaxies is crucial for understanding the evolution of galaxies. In galaxies, ultraviolet (UV) light emitted by recently formed massive stars is attenuated by dust, which is also produced by star formation (SF) activity, and is reemitted at mid- and far- infrared (IR) wavelengths. In this study, we investigate the star formation rate (SFR) and dust extinction using UV and IR data. We selected local galaxies which are detected at AKARI FIS 90 um and matched the IRAS IIFSCz 60 um select catalog. We measured FUV and NUV flux densities from GALEX images. We examined the SF and extinction of Local galaxies using four bands of AKARI. Then, we calculated FUV and total IR luminosities, and obtained the SF luminosity, L_{SF}, the total luminosity related to star formation activity, and the SFR. We find that in most galaxies, L_{SF} is dominated by L_{dust}. We also find that galaxies with higher SF activity have a higher fraction of their SF hidden by dust. In fact, the SF of galaxies with SFRs >20 M_{sun}/yr is almost completely hidden by dust. Our results boast a significantly higher precision with respect to previously published works, due to the use of much larger object samples from the AKARI and GALEX all sky surveys.

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