.png){kind=icon}
返回
The Fermi blazars' divide
.png){kind=icon}
OA
AI
DOI：10.1111/j.1745-3933.2009.00673.x.png)
.png){kind=icon}
.png){kind=icon}
分享.png){kind=icon}
收藏
摘要
En 中文
Flat-spectrum radio quasars (FSRQs) and BL Lac objects detected in the first three months of the Fermi survey neatly separate in the gamma-ray spectral index versus gamma-ray luminosity plane. BL Lac objects are less luminous and have harder spectra than broad-line blazars. We suggest that this division has its origin in the different accretion regimes of the two classes of objects. Using the gamma-ray luminosity as a proxy for the observed bolometric one, we show that the boundary between the two subclasses of blazars can be associated with the threshold between the regimes of optically thick accretion discs and of radiatively inefficient accretion flows, which lies at an accretion rate of the order of 10(-2) the Eddington rate. The spectral separation in hard (BL Lacs) and soft (FSRQs) objects can then result from the different radiative cooling suffered by the relativistic electrons in jets propagating in different ambients. We argue that the bulk of the most luminous blazars already detected by Fermi should be characterized by large black hole masses, around 10(9) solar masses, and predict that lowering the. gamma-ray flux threshold the region of the alpha(gamma)-L(gamma) plane corresponding to steep spectral indices and lower luminosities will be progressively populated by FSRQs with lower mass black holes, while the region of hard spectra and large luminosities will remain forbidden.
Keyword:
radiation mechanisms: non-thermal
BL Lacertae objects: general
quasars: general
gamma-rays: theory
AI总结
对已上传原文的论文进行重点信息的提取，主要内容包括：简要概述、研究摘要、背景介绍、关键亮点、图文解析、展望与总结。
期刊
IF:
4.8
论文数:
7.1W
被引数:
25.0W
机构
引用论文
20 cm VLA survey of Abell clusters of galaxies .6. Radio/optical luminosity functions.png)
ASTRONOMICAL JOURNAL
ASTRONOMICAL JOURNALIF5.1
PREAI
分享收藏Does the blazar gamma-ray spectrum harden with increasing flux?: Analysis of 9 years of EGRET dataOAAI
OAAI分享收藏
查看更多内容