BLazar天体的光变及多波段能谱特性  

The Variability and Multi-band Spectral Energy Properties of Blazars

作　　者：戴本忠[1] 

机构地区：[1]中国科学院云南天文台,云南昆明650011

出　　处：《云南天文台台刊》2002年第1期61-62,共2页Publications of the Yunnan Observatoty

摘　　要：本文综述了活动星系核 ,特别是blazar天体的研究现状 ,对blazar天体的多波段与多波段能谱特性研究进行了较为详细的评述。主要的研究工作包括以下内容 :(一 )γ噪blazar天体的短时标光变研究 ,通过对 1 6个γ噪blazar天体 (其中包括全部已证认和观测到VHEγ射线爆发的可能甚高能γ射线源 )自 1 998年的光学观测及光变分析研究表明 ,短时标光变 (小时量级 )是GeVγ噪blazar天体的普遍特性 ,光变幅度通常可达 0 .6mag/h ,对PKS 1 51 0 -0 89类星体的观测发现在一个小时内对象变暗 2个星等 ,对如此激烈的光变变暗目前的理论还不能很好的解释 ,但它同样反映了辐射区域的内部结构 ;而对TBLs的监测表明 ,其光学波段的短时标光变没有其他对象激烈 ,出现的频度和振幅变化都较小 ;(二 )在研究γ噪blazar天体光变时 ,研究了寄主星系对光变的影响 ,得到了 1ES 2 3 44 + 51 4的光变与PSF的FWHM的关联 ,表明随着大气视宁度的下降 (即FWHM变大 ) ,对象变暗 ,即由于寄主星系的影响从而导致假光变的产生 ;(三 )引进两个多波段复合谱指数 ,αxox=αox-αx 及αoro=αor-αo。对样本的统计研究表明 ,RBLs是能谱特性界于XBLs和OVVs之间的一类中间态 ,所得结果支持了Sambrunaetal.( 1 996)大样本多波段能谱分布特性的统计研?In the present thesis,the basic properties and research results about the active galactic nuclei (AGNs) are reviewed.It is focused on the multiband observations and the properties of multiband spectral energy distributions (SEDs) of blazars that would constraint the emission models of blazars.Our main work and results are as follows.(1)studying on the short timescale variability of γ-ray blazars.Our CCD monitoring campaign from 1998 has monitored 16 γ-ray blazars,including all the TeV sources and some suspicious TeV objects.The observational results show that the short timescale (about 1 hour) variability is the common property for the GeV γ-ray blazars,and the amplitude variations in each optical band (B,V,R,I) could reach to 0.6mag/hour.The GeV γ-ray-loud source,PKS 1510-089,was very active during our observation period,and it showed an apparent variation of 2.0mag within 41 minutes in the R band.This is the most violently rapid variability in the optical monitoring program since 1982.For this rapid dimming variability phenomenon,there is not any suitable theoretical explanation so far,however, this is the reflection of emission region structure.As for the TeV γ-ray blazars,the short timescale variability in the optical band is less drastic than GeV γ-ray blazars in both the amplitude and timescale;(2)The influence of variable seeing conditions on the observations was investigated.There is weak correlation between the observed variability and the local seeing conditions for the objects 1ES 2344+514.This implies that the source brightness decreased,while the FWHM of PSF increased,removing more light from the aperture,i.e. there would be some spurious variation influenced by variable seeing conditions.(3)The two composite color-color indices α xox =α ox -αx and α oro =α or -αo are introduced.The statistical results for the selected samples show that the RBLs are intermediate between the XBLs and the OVV quasars as suggested by Sumbruna et al.(1996).(4)The overview of the VHE

关 键 词：活动星系核 BLAZAR天体 光变 多波段能谱特性 Γ射线 统一模型 

分 类 号：P157.7[天文地球—天文学]