类星体0917＋62快速射电变化和星际折射闪烁

RAPID RADIO VARIATIONS OF QSO 0917+62 AND INTERSTELLAR REFRACTIVE SCINTILLATION

本文分析类星体０９１７＋６２在波长６ｃｍ和１１ｃｍ上快速变化（时标１天）的结构函数．讨论在什么条件下，这种快速变化可用星际折射闪烁来解释．结果表明，折射闪烁解释对星际介质和射电源结构提出了相当明确的限制：散射介质应为连续介质，其有效距离应０．４ｋｐｃ；射电源应包含０．０５—０．１ｍａｓ的致密结构．对快变射电源方向上脉冲星的测量以确定星际介质特性和用ＶＬＢＩ测量快变射电源中的小角径成分，将是检验星际折射闪烁解释的必要途径．

The structure functions of the rapid radio variations in QSO 0917+ 62 at λ6cm and λ11cm are analysed and interpreted in terms of interstellar refractive scintillation.It is shown that this interpretation implies some stringent constraints on the angular structure of the source and the scattering medium:the effective distance of the scattering medium should be less than～0.4kpc and the source should contain a compact component of angular radius less than～0.050 0.1mas.Constraints on the scattering strength of the medium are also discussed.In order to test the RISS interpretation measurements on pulsars in the directions towards the rapidly varying radio sources to determine the properties of the interstellar medium and space VLBI measurements of the small angular components in these sources are desirable.