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尘埃颗粒尺寸在活动星系核环面尘埃模型中的作用

The role of grain size in AGN torus dust models

Omaira González-Martín, Cristina Ramos Almeida, Jacopo Fritz, Almudena Alonso-Herrero, Sebastian F. Hönig, Patrick F. Roche, Donaji Esparza-Arredondo, Ismael Ga… 展开作者

Omaira González-Martín, Cristina Ramos Almeida, Jacopo Fritz, Almudena Alonso-Herrero, Sebastian F. Hönig, Patrick F. Roche, Donaji Esparza-Arredondo, Ismael García-Bernete, Santiago García-Burillo, Natalia Osorio-Clavijo, Ulises Reyes-Amador, Marko Stalevski, César Victoria-Ceballos

AI总结:

本文通过引入尘埃颗粒尺寸参数构建新的AGN环面SED库[GoMar23],拟合68个近邻AGN红外光谱,证明颗粒尺寸显著改善拟合,并为AGN附近尘埃颗粒生长提供初步证据。

摘要:

通过与模型对比,拟合活动星系核(AGN)核区红外光谱可以对尘埃性质、分布和几何结构施加约束。然而,目前可用的模型均无法完全描述现有AGN的观测结果。在探索最少的方面中,本文聚焦于尘埃颗粒尺寸的作用。我们向学界提供了一个新的光谱能量分布(SED)库,以下简称[GoMar23]模型,该模型基于此前发展的两相环面模型,并将颗粒尺寸作为模型参数纳入,以最大颗粒尺寸Psize或等效的质量加权平均颗粒尺寸<P>进行参数化。我们使用SKIRT代码生成了691,200个SED,其中最大颗粒尺寸可在Psize=0.01–10.0微米(<P>=0.007–3.41微米)范围内变化。我们将这一新库及若干现有库拟合到由68个近邻且高光度的AGN组成的样本上,这些AGN具有以AGN加热尘埃为主导的Spitzer/IRS光谱。我们发现[GoMar23]模型能够充分复现多达85–88%的光谱。尘埃颗粒尺寸参数在多达90%的这些光谱中显著改善了最终拟合。统计检验表明,颗粒尺寸是拟合过程中第三重要的参数(仅次于环面尺寸和半张角)。与纯团块模型相比,我们的模型对前景消光的要求更低。我们发现样本中41%的天体要求最大尘埃颗粒尺寸达到Psize=10微米(<P>=3.41微米)。尽管如此,我们也指出,盘+风和团块环面模型仍然是复现不可忽略比例天体光谱所必需的,这表明需要多种尘埃几何结构来解释AGN的红外连续谱。本工作为AGN附近尘埃颗粒生长提供了初步证据。

英文摘要:

Fits the infrared spectra from the nuclear regions of AGN can place constraints on the dust properties, distribution, and geometry by comparison with models. However, none of the currently available models fully describe the observations of AGN currently available. Among the aspects least explored, here we focus on the role of dust grain size. We offer the community a new spectral energy distribution (SED) library, hereinafter [GoMar23] model, which is based on the two-phase torus model developed before with the inclusion of the grain size as a model parameter, parameterized by the maximum grain size Psize or equivalently the mass-weighted average grain size < P >. We created 691,200 SEDs using the SKIRT code, where the maximum grain size can vary within the range Psize = 0.01 - 10.0um ( < P >= 0.007 - 3.41um). We fit this new and several existing libraries to a sample of 68 nearby and luminous AGNs with Spitzer/IRS spectra dominated by AGN-heated dust. We find that the [GoMar23] model can adequately reproduce up to 85-88% of the spectra. The dust grain size parameter significantly improves the final fit in up to 90% of these spectra. Statistical tests indicate that the grain size is the third most important parameter in the fitting procedure (after the size and half opening angle of the torus). The requirement of a foreground extinction by our model is lower compared to purely clumpy models. We find that 41% of our sample requires that the maximum dust grain size is as large as Psize =10um (< P >= 3.41um). Nonetheless, we also remark that disk+wind and clumpy torus models are still required to reproduce the spectra of a non-negligible fraction of objects, suggesting the need for several dust geometries to explain the infrared continuum of AGN. This work provides tentative evidence for dust grain growth in the proximity of the AGN.

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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