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arXiv 0811.2420astro-ph
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Sloan数字巡天的恒星形成率的发射线校准

Emission-lines calibrations of the Star Formation Rate from the Sloan Digital Sky Survey

B. Argence, F. Lamareille

摘要:

我们的目标是研究现有的恒星形成率校准的基础上发射线光度,并提供新的。我们使用SDSS数据发布DR 4,它给出了超过10万个恒星形成星系的恒星形成率和发射线光度。我们确认,最好的结果是获得与Halpha校准。该校准的不确定度为0.17 dex。我们表明,人们必须仔细检查用于推导尘埃衰减的方法,并使用适当的校准:在某些情况下,标准的标度律必须由一个更一般的幂律取代。当对数据进行尘埃衰减校正但未观察到H α发射谱线时,使用H β发射谱线必须优于[OII]3727发射谱线。在未经校正的数据的情况下,尘埃衰减的校正可以假设为一个恒定的值,但我们表明,这种方法会导致差的结果,在色散和剩余斜率。例如基于绝对星等的自洽校正在色散方面给出更好的结果,但仍然受到系统偏移和/或残余斜率的影响。当同时使用观测到的[OII]3727和Hbeta发射谱线时,获得了未对尘埃衰减进行校正的数据的最佳结果。该校准的不确定度为0.23 dex。

英文摘要:

Our goal is to study the existing star formation rate calibrations based on emission-line luminosities and to provide new ones. We use the SDSS data release DR4, which gives star formation rates and emission-line luminosities of more than 100000 star-forming galaxies. We confirm that the best results are obtained with the Halpha calibration. This calibration has an uncertainty of 0.17 dex. We show that one has to check carefully the method used to derive the dust attenuation and to use the adequate calibration: in some cases, the standard scaling law has to be replaced by a more general power law. When data is corrected for dust attenuation but the Halpha emission line not observed, the use of the Hbeta emission line, has to be preferred to the [OII]3727 emission line. In the case of uncorrected data, the correction for dust attenuation can be assumed as a constant value but we show that such method leads to poor results, in terms of dispersion and residual slope. Self-consistent corrections, based e.g. on the absolute magnitude, give better results in terms of dispersion but still suffer from systematic shifts, and/or residual slopes. The best results with data not corrected for dust attenuation are obtained when using the observed [OII]3727 and Hbeta emission lines together. This calibration has an uncertainty of 0.23 dex.

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