Why are some BL Lacertaes detected by Fermi, but others not?

	Why are some BL Lacertaes detected by Fermi, but others not?
	Wu, Zhongzu 1; Jiang, Dongrong 2; Gu, Minfeng2 ; Chen, Liang2
刊名	ASTRONOMY & ASTROPHYSICS
	2014-02-01
卷号	562 期号:562 页码:A64
关键词	galaxies: active BL Lacertae objects: general galaxies: jets galaxies: nuclei
英文摘要	By cross-correlating an archival sample of 170 BL Lacs with a 2 year Fermi/LAT AGN sample, we have compiled a sample of 100 BL Lacs with Fermi detection (FBLs) and a sample of 70 non-Fermi BL Lacs (NFBLs). We compared various parameters of FBLs with those of NFBLs, including the redshift, the low-frequency radio luminosity at 408 MHz (L-408 MHz), the absolute magnitude of host galaxies (M-host), the polarization fraction from the NVSS survey (P-NVSS), the observed arcsecond scale radio core flux at 5 GHz (F-core), and the jet Doppler factor. All these parameters are directly measured or derived from available data in the literature. We found that the Doppler factor is on average greater in FBLs than in NFBLs, and the Fermi gamma-ray detection rate is higher in sources with higher Doppler factor. In contrast, there are no significant differences in terms of the intrinsic parameters of redshift, L-408 MHz, M-host, and P-NVSS. FBLs seem to have a higher probability of exhibiting measurable proper motion. These results strongly indicate a stronger beaming effect in FBLs compared to NFBLs. The radio core flux is found to be strongly correlated with gamma-ray flux, which remains after excluding the common dependence of the Doppler factor. At the fixed Doppler factor, FBLs have systematically larger radio core flux than NFBLs, implying lower gamma-ray emission in NFBLs since the radio and gamma-ray flux are significantly correlated. Our results indicate that the Doppler factor is an important parameter of gamma-ray detection, that the non-detection of gamma-ray emission in NFBLs is probably due to low beaming and/or low intrinsic gamma-ray flux, and the gamma-rays are very likely produced cospatially with the arcsecond-scale radio core radiation and mainly through the SSC process.
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 ; LARGE-AREA TELESCOPE ; RELATIVISTIC JETS ; VLBI OBSERVATIONS ; COMPLETE SAMPLE ; BRIGHT BLAZARS ; RADIO ; OBJECTS ; CATALOG ; VARIABILITY
收录类别	SCI
语种	英语
WOS记录号	WOS:000332161800009
内容类型	期刊论文
源URL	[http://119.78.226.72/handle/331011/18182]
专题	上海天文台_星系宇宙学重点实验室
作者单位	1.Guizhou Univ, Coll Sci, Guiyang 550025, Peoples R China 2.Chinese Acad Sci, Shanghai Astron Observ, Key Lab Res Galaxies & Cosmol, Shanghai 200030, Peoples R China
推荐引用方式 GB/T 7714	Wu, Zhongzu,Jiang, Dongrong,Gu, Minfeng,et al. Why are some BL Lacertaes detected by Fermi, but others not?[J]. ASTRONOMY & ASTROPHYSICS,2014,562(562):A64.
APA	Wu, Zhongzu,Jiang, Dongrong,Gu, Minfeng,&Chen, Liang.(2014).Why are some BL Lacertaes detected by Fermi, but others not?.ASTRONOMY & ASTROPHYSICS,562(562),A64.
MLA	Wu, Zhongzu,et al."Why are some BL Lacertaes detected by Fermi, but others not?".ASTRONOMY & ASTROPHYSICS 562.562(2014):A64.