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arXiv 1409.0847astro-ph.GA
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Spitzer本地卷遗留(LVL)SED和物理性质

Spitzer Local Volume Legacy (LVL) SEDs and Physical Properties

David O. Cook, Daniel A. Dale, Benjamin D. Johnson, Liese Van Zee, Janice C. Lee, Robert C. Kennicutt, Daniela Calzetti, Shawn M. Staudaher, Charles W. Engelbracht

摘要:

我们提出的全色光谱能量分布(SED)的本地体积遗产(LVL)调查,其中包括258个附近的星系($D<$ 11 Mpc)。波长覆盖范围从紫外线到红外线(1500 $\textrmÅ$到24 $μ$ m),其被用于导出全局物理性质(即,恒星形成率、恒星质量、尘埃导致的内部灭绝)。通过这些数据,我们发现了观察到的和物理性质之间的颜色-颜色关系和相关趋势(即,光学星等和尘埃性质、光学颜色和特定恒星形成率、紫外-红外颜色和金属丰度)。SED被不同的星系属性分组,以揭示每个属性如何影响这些SED的观测形状。此外,由于LVL的体积有限的性质,我们利用矮占主导地位的星系样本,以测试恒星形成的关系,建立与更高质量的星系样本。我们发现很好的协议与恒星形成的“主序列”的关系,但发现在红外“主序列”在低光度的系统偏差。这种偏差是由于抑制多环芳烃(PAH)的形成在低金属含量的环境和/或多环芳烃的破坏在更强的辐射场发生在sSFR的建议阈值附近的log($sSFR$)$\sim$ $-$ 10.2。

英文摘要:

We present the panchromatic spectral energy distributions (SEDs) of the Local Volume Legacy (LVL) survey which consists of 258 nearby galaxies ($D<$11 Mpc). The wavelength coverage spans the ultraviolet to the infrared (1500 $\textrmÅ$ to 24 $μ$m) which is utilized to derive global physical properties (i.e., star formation rate, stellar mass, internal extinction due to dust.). With these data, we find color-color relationships and correlated trends between observed and physical properties (i.e., optical magnitudes and dust properties, optical color and specific star formation rate, and ultraviolet-infrared color and metallicity). The SEDs are binned by different galaxy properties to reveal how each property affects the observed shape of these SEDs. In addition, due to the volume-limited nature of LVL, we utilize the dwarf-dominated galaxy sample to test star formation relationships established with higher-mass galaxy samples. We find good agreement with the star-forming "main-sequence" relationship, but find a systematic deviation in the infrared "main-sequence" at low luminosities. This deviation is attributed to suppressed polycyclic aromatic hydrocarbon (PAH) formation in low metallicity environments and/or the destruction of PAHs in more intense radiation fields occurring near a suggested threshold in sSFR at a value of log($sSFR$) $\sim$ $-$10.2.

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