arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2212.05686astro-ph.GA
收藏

低光度活动星系核中小PAH分子被激波破坏的证据

Evidence that Shocks Destroy Small PAH Molecules in Low-luminosity Active Galactic Nuclei

Lulu Zhang, Luis C. Ho, Aigen Li

摘要:

我们结合映射模式的中红外斯皮策光谱与互补的红外成像进行空间分辨研究的多环芳烃(PAH)的排放从66个附近的星系,大致均匀地分为恒星形成系统和低光度活动星系核(AGN)的中心区域。结合类星体的类似测量,我们的目标是了解多环芳烃在广泛的黑洞吸积功率的物理特性,确定观测诊断,可用于探测活动星系核对宿主星系的影响的目标。而PAH的排放密切相关的远紫外光度在恒星形成的地区,活动星系核的空间分辨区域往往是PAH不足。此外,活动星系核区的PAH平均值较小,为6.2 μm/7.7 μm,而PAH平均值较大,为11.3 μm/7.7 μm。虽然目前的数据是高度限制性的,他们认为,这些异常PAH波段比不能解释的活动星系核辐射场的影响单独。相反,他们暗示,小颗粒可能会被破坏的辐射过程和冲击,这是必然联系到喷流和外流优先与高度次爱丁顿,辐射效率低下的活动星系核的综合影响。虽然类星体也呈现出PAH赤字和不寻常的PAH波段比,但它们的特征与在更弱的吸积活动星系核中观察到的特征相比在细节上有所不同,这可能是它们能量反馈模式的根本差异的一个指标。

英文摘要:

We combined mapping-mode mid-infrared Spitzer spectra with complementary infrared imaging to perform a spatially resolved study of polycyclic aromatic hydrocarbons (PAHs) emission from the central regions of 66 nearby galaxies, roughly evenly divided into star-forming systems and low-luminosity active galactic nuclei (AGNs). In conjunction with similar measurements available for quasars, we aim to understand the physical properties of PAHs across a broad range of black hole accretion power, with the goal of identifying observational diagnostics that can be used to probe the effect of AGNs on the host galaxy. Whereas the PAH emission correlates tightly with far-ultraviolet luminosity in star-forming regions, the spatially resolved regions of AGNs tend to be PAH-deficient. Moreover, AGN regions exhibit on average smaller PAH 6.2 μm/7.7 μm and larger PAH 11.3 μm/7.7 μm band ratios. Although the current data are highly restrictive, they suggest that these anomalous PAH band ratios cannot be explained by the effects of the AGN radiation field alone. Instead, they hint that small grains may be destroyed by the combined effects of radiative processes and shocks, which are plausibly linked to jets and outflows preferentially associated with highly sub-Eddington, radiatively inefficient AGNs. While quasars also present a PAH deficit and unusual PAH band ratios, their characteristics differ in detail compared to those observed in more weakly accreting AGNs, a possible indicator of fundamental differences in their modes of energy feedback.

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。

↑