1、Mid-infrared Variability of Changing-look AGNsOutline Introduction a.Background of changing-look AGNs b.A brief review of previous results Our worka.Data and Sample selectionb.Analysisc.Discussion Conclusion&Future work Background-Unification Model of AGNI2Two different typesRunnoe 2017Shappee 2014A
2、ppearing BELsDisappearing BELsBackground-The challenge of Unification Model2003 2015Background Changing-look(CL)AGNs:have emerging or disappearing Board Emission Lines(BELs)phenomenon Two main modelsVariable obscuration:based on Unified Model Variable accretion:turn off/turn on of AGNs-evolutionary
3、view Our worksWide-field Infrared Survey Explorer(WISE photometric data)W1 band:3.4m,W2 band:4.6mData&Method All the changing-look AGNs in literature Additional Data:V-band light curves:Catalina Real-time Transient Survey(CRTS)S82 photometric data Method:Exclude immediate types Large variation in in
4、frared bands No source contamination within 6”2410Disappearing BELs (type 1 2)J1011,Runnoe et al.2016 Appearing BELs (type 2 1)Appearing BELs (type 2 1 2?)Reversible changeDiscussionExtinctionDynamical time scale of the obscurationDiscussionExtinctionDynamical time scale of the obscurationCandidates
5、Sheng et al.(2017 in prep)Optical spectroscopic follow-upJ1115+0544typical early-type galaxySDSSP200Provided by Lin Yan,P200 time from Shri Kulkarnis programCandidatesJiang et al.(2017 in prep)ConclusionFind significant decrease in infrared bands;Exclude the extinction or obscuration.The 10 CL AGNs
6、likely due to variation of accretion rate Some objects show reversible change between Type 1 and Type 2Find a list sample of interesting candidatesFuture workInfrared selected changing-look candidates:If we have enough samples of turn-on/turn-off AGNs explore their evolution and constrain the duty c
7、ycleFollow-up observation:Broad line region/SED echo to variation of accretion rate study the structure of AGNs 获得的望远镜时间国家天文台丽江国家天文台丽江2.4米望远镜：米望远镜：2016年 2 月22-24日 3个后半夜 大雾大雪2017年12月11-13日 3个后半夜 2018年 1 月20-23日 4个前半夜 2018年 3 月22-24日 3个后半夜 共计共计10个半夜个半夜 美国帕罗马天文台海尔美国帕罗马天文台海尔5.1米：米：2017年 1月 5个整夜 大雾2018年 1月 2-5 日 4个整夜
