BL Lac object S5 2007+777 has been classified as a HYMOR(Hybrid Morphology radio source) for its hybrid FR I and FR II radio morphology.It is one of four BL Lac objects with a kpc scale extended X-ray jet.In this pape...BL Lac object S5 2007+777 has been classified as a HYMOR(Hybrid Morphology radio source) for its hybrid FR I and FR II radio morphology.It is one of four BL Lac objects with a kpc scale extended X-ray jet.In this paper,we searched the unpublished European VLBI Network(EVN) archived high resolution data for this source,and present the high resolution radio structure.The EVN images all show a core-jet structure in 1.6,5 and 8 GHz.In combination with the VLA data in the literature,we found position angle differences(△PA) of about 10°-20° between pc and kpc scale jet structures.The brightness temperature estimated from multi-band EVN images are around 1011.2-1011.8 K,from which the Doppler factor ranges from 3.2 to 12.0.We found significant flux variations of the radio core in 1.6 and 5 GHz,from which we derived the variability in brightness temperature Tvar to be 1013.6 K and 1014.0 K,corresponding to the Doppler factors of 9.3 and 12.4,respectively.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 10633010, 10703009, 10833002 and 10821302)the National Basic Research Program of China (Grant No. 2009CB824800)+2 种基金the Study Abroad Fund from the Ministry of Education of China (Grant No. O922571001)the Science Foundation of Guizhou Province (Grant No. 20092064)the Science Foundation of Guizhou University (Grant No. 2008035)
文摘BL Lac object S5 2007+777 has been classified as a HYMOR(Hybrid Morphology radio source) for its hybrid FR I and FR II radio morphology.It is one of four BL Lac objects with a kpc scale extended X-ray jet.In this paper,we searched the unpublished European VLBI Network(EVN) archived high resolution data for this source,and present the high resolution radio structure.The EVN images all show a core-jet structure in 1.6,5 and 8 GHz.In combination with the VLA data in the literature,we found position angle differences(△PA) of about 10°-20° between pc and kpc scale jet structures.The brightness temperature estimated from multi-band EVN images are around 1011.2-1011.8 K,from which the Doppler factor ranges from 3.2 to 12.0.We found significant flux variations of the radio core in 1.6 and 5 GHz,from which we derived the variability in brightness temperature Tvar to be 1013.6 K and 1014.0 K,corresponding to the Doppler factors of 9.3 and 12.4,respectively.
