Absorption of 10-200 GeV gamma rays by radiation from broad-line regions in blazars

	Absorption of 10-200 GeV gamma rays by radiation from broad-line regions in blazars
	Liu HT(刘洪涛)1,2 ; Bai JM(白金明)1
刊名	ASTROPHYSICAL JOURNAL
	2006-12-20
卷号	653 期号:2 页码:1089-1097
关键词	BL Lacertae objects : general gamma rays : theory
ISSN号	0004-637X
通讯作者	Liu, HT (reprint author), Chinese Acad Sci, Natl Astron Observ, Yunnan Astron Observ, Kunming, Yunnan, Peoples R China.
产权排序	第一完成单位
英文摘要	In this paper, we study the photon-photon pair production optical depth for gamma rays with energies from 10 to 200 GeV emitted by powerful blazars due to the diffuse radiation field of the broad-line region (BLR). There are four key parameters in the BLR model employed to determine the gamma-gamma attenuation optical depth of these gamma rays. They are the gamma-ray emitting radius R-gamma, the BLR luminosity L-BLR, the BLR half thickness h, and the ratio tau(BLR)/f(cov) of the Thomson optical depth to the covering factor of BLR. For FSRQs, on average, it is impossible for gamma rays with energies from 10 to 200 GeV to escape from the diffuse radiation field of the BLR. If GLAST could detect these gamma rays for most of FSRQs, the gamma-ray emitting region is likely to be outside the cavity formed by the BLR. Otherwise, the emitting region is likely to be inside the BLR cavity. As examples, we estimate the photon-photon absorption optical depth of gamma rays with energies from 10 to 200 GeV for two powerful blazars, HFSRQ PKS 0405-123 and FSRQ 3C 279. Comparing our results with GLAST observations in the future could test whether the model employed and the relevant assumptions in this paper are reliable and reasonable, and then limit constraints on the position of the gamma-ray emitting region relative to the BLR and the properties of the BLR.
学科主题	Astronomy & Astrophysics
WOS标题词	Science & Technology ; Physical Sciences
类目[WOS]	Astronomy & Astrophysics
研究领域[WOS]	Astronomy & Astrophysics
关键词[WOS]	ACTIVE GALACTIC NUCLEI ; 2ND EGRET CATALOG ; EMISSION-LINES ; PAIR CASCADES ; RADIO QUASARS ; TELESCOPE ; HESS ; LUMINOSITY ; SCHEMES ; PHOTONS
收录类别	SCI
原文出处	http://iopscience.iop.org/0004-637X/653/2/1089/
语种	英语
WOS记录号	WOS:000242955200020
内容类型	期刊论文
源URL	[http://ir.ynao.ac.cn/handle/114a53/4943]
专题	云南天文台_高能天体物理研究组
作者单位	1.National Astronomical Observatories/Yunnan Astronomical Observatory, the Chinese Academy of Sciences, Kunming, Yunnan, China 2.Graduate School of the Chinese Academy of Sciences, Beijing, China
推荐引用方式 GB/T 7714	Liu HT,Bai JM. Absorption of 10-200 GeV gamma rays by radiation from broad-line regions in blazars[J]. ASTROPHYSICAL JOURNAL,2006,653(2):1089-1097.
APA	Liu HT,&Bai JM.(2006).Absorption of 10-200 GeV gamma rays by radiation from broad-line regions in blazars.ASTROPHYSICAL JOURNAL,653(2),1089-1097.
MLA	Liu HT,et al."Absorption of 10-200 GeV gamma rays by radiation from broad-line regions in blazars".ASTROPHYSICAL JOURNAL 653.2(2006):1089-1097.