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arXiv 0905.4439astro-ph.CO
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根据修正后的[ OIII ]计算的2型AGN的热光度:没有Eddington有限源的证据

The bolometric luminosity of type 2 AGN from extinction-corrected [OIII]: no evidence for Eddington-limited sources

A. Lamastra, S. Bianchi, G. Matt, G. C. Perola, X. Barcons, F. J. Carrera

摘要:

最近有人声称,2型活动星系核中有相当一部分是在爱丁顿极限附近甚至之上吸积的。在2型活动星系核中,辐射热光度(L_b)一般由[OIII]发射线光度(L_OIII)来推断。因此,为了估算这些活动星系核的辐射热光度,关键的问题是要知道对L_O III的辐射热校正。一个复杂的事实是,所观察到的L_OIII的消光,可能是由于在窄线区域的尘埃的影响。修正后的[OIII]光度(L^c_OIII)是比L_OIII更好的核光度估算值。然而,到目前为止,只有辐射热校正适用于未经校正的L_OIII已评估。本文用测辐射热改正C_O_III =L_b/L^c_O_III来计算SDSS天体样本中2型活动星系核的爱丁顿比。我们从文献中收集了61个对L^c_O Ⅲ和X射线光度(L_X)都有可靠估计的源。为了估计C_O III,我们将观测到的L^c_O III和L_X之间的相关性与X射线辐射热校正相结合。与之前的研究相反,我们发现L^c_OIII和L_X之间存在线性相关性。我们使用Marconi等人(2004)的光度相关X射线辐射热校正估算了C_OIII,发现在logL_OIII=38-40、40-42和42-44的光度范围内C_OIII的平均值分别为87、142和454。我们用它来计算在0.3<z<0.4的2型SDSS活动星系核的爱丁顿比分布,我们发现这些源在它们的爱丁顿极限附近没有吸积,与以前的说法相反。

英文摘要:

There have been recent claims that a significant fraction of type 2 AGN accrete close or even above the Eddington limit. In type 2 AGN the bolometric luminosity (L_b) is generally inferred from the [OIII] emission line luminosity (L_OIII). The key issue, in order to estimate the bolometric luminosity in these AGN, is therefore to know the bolometric correction to be applied to L_OIII. A complication arises from the fact that the observed L_OIII is affected by extinction, likely due to dust within the narrow line region. The extinction-corrected [OIII] luminosity (L^c_OIII) is a better estimator of the nuclear luminosity than L_OIII. However, so far only the bolometric correction to be applied to the uncorrected L_OIII has been evaluated. This paper is devoted to estimate the bolometric correction C_OIII=L_b/L^c_OIII in order to derive the Eddington ratios for the type 2 AGN in a sample of SDSS objects. We have collected from the literature 61 sources with reliable estimate of both L^c_OIII and X-ray luminosities (L_X). To estimate C_OIII, we combined the observed correlation between L^c_OIII and L_X with the X-ray bolometric correction. We found, contrary to previous studies, a linear correlation between L^c_OIII and L_X. We estimated C_OIII using the luminosity-dependent X-ray bolometric correction of Marconi et al. (2004), and we found a mean value of C_OIII in the luminosity ranges log L_OIII=38-40, 40-42, and 42-44 of 87, 142 and 454 respectively. We used it to calculate the Eddington ratio distribution of type 2 SDSS AGN at 0.3<z<0.4 and we found that these sources are not accreting near their Eddington limit, contrary to previous claims.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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