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arXiv 1209.3498astro-ph.CO
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大样本明亮致密星系的Hα和UV光度及恒星形成率

Hα and UV luminosities and star formation rates in a large sample of luminous compact galaxies

S. L. Parnovsky, I. Y. Izotova, Y. I. Izotov

摘要:

利用银河演化探测器(GALEX)对800个明亮致密星系(LCG)的紫外连续谱和Hα发射谱线的观测结果,对恒星形成率(SFR)进行了统计研究。这个样本中的半导体有一个紧凑的结构,包括一个或几个活跃的恒星形成区域。在高红移z > 2 - 3时,全球星系的特征(金属丰度、光度、恒星质量)介于附近的蓝致密矮(BCD)星系和莱曼破裂星系(LBG)之间。对SFR进行了星际消光校正,星际消光来自于光学斯隆数字巡天(SDSS)光谱。我们发现,由远紫外(FUV)和近紫外(NUV)范围内的星系光度导出的SFR在0.18 ~ 113 MSun/yr的范围内变化,中值分别为3.8 MSun/yr和5.2 MSun/yr。发现光度L(Hα)和L(UV)与年轻恒星星族质量、星暴年龄和星系金属丰度之间存在简单的回归关系。讨论了L(Hα)、L(FUV)和L(NUV)随星暴年龄的演化,并介绍了恒星形成的新特征,即零星暴年龄时的初始Hα、FUV和NUV光度。

英文摘要:

We present the results of a statistical study of the star formation rates (SFR) derived from the Galaxy Evolution Explorer (GALEX) observations in the ultraviolet continuum and in the Hαemission line for a sample of about 800 luminous compact galaxies (LCGs). Galaxies in this sample have a compact structure and include one or several regions of active star formation. Global galaxy characteristics (metallicity, luminosity, stellar mass) are intermediate between ones of the nearby blue compact dwarf (BCD) galaxies and Lyman-break galaxies (LBGs) at high redshifts z > 2 - 3. SFRs were corrected for interstellar extinction which was derived from the optical Sloan Digital Sky Survey (SDSS) spectra. We find that SFRs derived from the galaxy luminosities in the far ultraviolet (FUV) and near ultraviolet (NUV) ranges vary in a wide range from 0.18 M_Sun/yr to 113 M_Sun/yr with median values of 3.8 M_Sun/yr and 5.2 M_Sun/yr, respectively. Simple regression relations are found for luminosities L(Hα) and L(UV) as functions of the mass of the young stellar population, the starburst age, and the galaxy metallicity. We consider the evolution of L(Hα), L(FUV) and L(NUV) with a starburst age and introduce new characteristics of star formation, namely the initial Hα, FUV and NUV luminosities at zero starburst age.

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